Month: October 2024

Building on research that has used empirical data to compare soil and above ground C stocks in vineyards and adjacent oak woodlands in California, this study sought to estimate the C composition of a vine, including the relative contributions of its component parts . By identifying the allometric relationships among trunk diameter, plant height, and other vine dimensions, growers could utilize a reliable mechanism for translating vine architecture and biomass into C estimates. In both natural and agricultural ecosystems, several studies have been performed using allometric equations in order to estimate above ground biomass to assess potential for C sequestration. For example, functional relationships between the ground-measured Lorey’s height and above ground biomass were derived from allometric equations in forests throughout the tropics. Similarly, functional relationships have been found in tropical agriculture for above ground, below ground, and field margin biomass and C. In the vineyard setting, however, horticultural intervention and annual pruning constrain the size and shape of vines making existing allometric relationships less meaningful, though it is likely that simple physical measurements could readily estimate above ground biomass. To date, most studies on C sequestration in vineyards have been focused on soil C as sinks and some attempts to quantify biomass C stocks have been carried out in both agricultural and natural systems. In vineyards, studies in California in the late 1990s have reported net primary productivity or total biomass values between 550 g C m−2 and 1100 g C m−2.

In terms of spatial distribution, hydroponic nft system some data of standing biomass collected by Kroodsma et al. from companies that remove trees and vines in California yielded values of 1.0–1.3 Mg C ha−1 year−1 woody C for nuts and stone fruit species, and 0.2–0.4 Mg C ha−1 year−1 for vineyards. It has been reported that mature California orchard crops allocate, on average, one third of their NPP to the harvested portion and mature vines 35–50% of the current year’s production to grape clusters. Pruning weight has also been quantified by two direct measurements which estimated 2.5 Mg of pruned biomass per ha for both almonds and vineyards. The incorporation of trees or shrubs in agroforestry systems can increase the amount of carbon sequestered compared to a monoculture field of crop plants or pasture. Additional forest planting would be needed to offset current net annual loss of above ground C, representing an opportunity for viticulture to incorporate the surrounding woodlands into the system. A study assessing C storage in California vineyards found that on average, surrounding forested wildlands had 12 times more above ground woody C than vineyards and even the largest vines had only about one-fourth of the woody biomass per ha of the adjacent wooded wildlands.The objectives of this study were to: measure standing vine biomass and calculate C stocks in Cabernet Sauvignon vines by field sampling the major biomass fractions ; calculate C fractions in berry clusters to assess C mass that could be returned to the vineyard from the winery in the form of rachis and pomace; determine proportion of perennially sequestered and annually produced C stocks using easy to measure physical vine properties ; and develop allometric relationships to provide growers and land managers with a method to rapidly assess vineyard C stocks. Lastly, we validate block level estimates of C with volumetric measurements of vine biomass generated during vineyard removal.

The study site is located in southern Sacramento County, California, USA , and the vineyard is part of a property annexed into a seasonal floodplain restoration program, which has since removed the levee preventing seasonal flooding. The ensuing vineyard removal allowed destructive sampling for biomass measurements and subsequent C quantification. The vineyard is considered part of the Cosumnes River appellation within the Lodi American Viticultural Area, a region characterized by its Mediterranean climate— cool wet winters and warm dry summers—and by nearby Sacramento-San Joaquin Delta breezes that moderate peak summer temperatures compared to areas north and south of this location. The study site is characterized by a mean summer maximum air temperature of 32 °C, has an annual average precipitation of 90 mm, typically all received as rain from November to April . During summer time, the daily high air temperatures average 24 °C, and daily lows average 10 °C. Winter temperatures range from an average low 5 °C to average high 15 °C . Total heating degree days for the site are approximately 3420 and the frost-free season is approximately 360 days annuall. Similar to other vineyards in the Lodi region, the site is situated on an extensive alluvial terrace landform formed by Sierra Nevada out wash with a San Joaquin Series soil . This soil-landform relationship is extensive, covering approximately 160,000 ha across the eastern Central Valley and it is used extensively for winegrape production. The dominant soil texture is clay loam with some sandy clay loam sectors; mean soil C content, based on three characteristic grab samples processed by the UC Davis Analytical Lab, in the upper 8 cm was 1.35% and in the lower 8–15 cm was 1.1% . The vineyard plot consisted of 7.5 ha of Cabernet Sauvignon vines, planted in 1996 at a density of 1631 plants ha−1 with flood irrigation during spring and summer seasons. The vines were trained using a quadrilateral trellis system with two parallel cordons and a modified Double Geneva Curtain structure attached to T-posts . Atypically, these vines were not grafted to rootstock, which is used often in the region to modify vigor or limit disease .In Sept.–Oct. of 2011, above ground biomass was measured from 72 vines. The vineyard was divided equally in twelve randomly assigned blocks, and six individual vines from each block were processed into major biomass categories of leaf, fruit, cane and trunk plus cordon . Grape berry clusters were collected in buckets, with fruit separated and weighed fresh in the field. Leaves and canes were collected separately in burlap sacks, and the trunks and cordons were tagged. Biomass was transported off site to partially air dry on wire racks and then fully dried in large ventilated ovens.

Plant tissues were dried at 60 °C for 48 h and then ground to pass through a 250 μm mesh sieve using a Thomas Wiley® Mini-Mill . Total C in plant tissues was analyzed using a PDZ Europa ANCA-GSL elemental analyzer at the UC Davis Stable Isotope Facility. For cluster and berry C estimations, grape clusters were randomly selected from all repetitions. Berries were removed from cluster rachis. While the berries were frozen, the seeds and skins were separated from the fruit flesh or “pulp”, and combined with the juice . The rachis, nft channel skins and seeds were dried in oven and weighed. The pulp was separated from the juice + pulp with vacuum filtration using a pre-weighed Q2 filter paper . The filter paper with pulp was oven dried and weighed to get insoluble solid fraction . The largest portion of grape juice soluble solids are sugars. Sugars were measured at 25% using a Refractometer PAL-1 . The C content of sugar was calculated at 42% using the formula of sucrose. Below ground biomass was measured by pneumatically excavating the root system with compressed air applied at 0.7 Mpa for three of the 12 sampling blocks, exposing two vines each in 8 m3 pits. A root restricting duripan, common in this soil, provided an effective rooting depth of about 40 cm at this site with only 5–10 fine and small roots able to penetrate below this depth in each plot. Roots were washed, cut into smaller segments and separated into four size classes , oven-dried at 60 °C for 48 h and weighed. Larger roots were left in the oven for 4 days. Stumps were considered part of the root system for this analysis.In vineyard ecosystems, annual C is represented by fruit, leaves and canes, and is either removed from the system and/or incorporated into the soil C pools, which was not considered further. Structures whose tissues remain in the plant were considered perennial C. Woody biomass volumes were measured and used for perennial C estimates. Cordon and trunk diameters were measured using a digital caliper at four locations per piece and averaged, and lengths were measured with a calibrated tape. Sixty vines were used for the analysis; twelve vines were omitted due to missing values in one or more vine fractions. All statistical estimates were conducted in R.The present study provides results for an assessment of vineyard biomass that is comparable with data from previous studies, as well as estimates of below ground biomass that are more precise than previous reports. While most studies on C sequestration in vineyards have focused on soil C, some have quantified above ground biomass and C stocks. For example, a study of grapevines in California found net primary productivity values between 5.5 and 11 Mg C ha−1—figures that are comparable to our mean estimate of 12.4 Mg C ha−1 . For pruned biomass, our estimate of 1.1 Mg C ha−1 were comparable to two assessments that estimated 2.5 Mg of pruned biomass ha−1 for both almonds and vineyards.

Researchers reported that mature orchard crops in California allocated, on average, one third of their NPP to harvestable biomass, and mature vines allocated 35–50% of that year’s production to grape clusters. Our estimate of 50% of annual biomass C allocated to harvested clusters represent the fraction of the structures grown during the season . Furthermore, if woody annual increments were considered this proportion would be even lower. Likewise the observed 1.7 Mg ha−1 in fruit represents ~14% of total biomass , which is within 10% of other studies in the region at similar vine densities. More importantly, this study reports the fraction of C that could be recovered from wine making and returned to the soil for potential long term storage. However, this study is restricted to the agronomic and environmental conditions of the site, and the methodology would require validation and potential adjustment in other locations and conditions. Few studies have conducted a thorough evaluation of below ground vine biomass in vineyards, although Elder field did estimate that fine roots contributed 20–30% of total NPP and that C was responsible for 45% of that dry matter. More recently, Brunori et al. studied the capability of grapevines to efficiently store C throughout the growing season and found that root systems contributed to between 9 and 26% of the total vine C fixation in a model Vitis vinifera sativa L. cv Merlot/berlandieri rupestris vineyard. The results of our study provide a utilitarian analysis of C storage in mature wine grape vines, including above and below ground fractions and annual vs. perennial allocations. Such information constitutes the basic unit of measurement from which one can then estimate the contribution of wine grapes to C budgets at multiple scales— fruit, plant or vineyard level—and by region, sector, or in mixed crop analyses. Our study builds on earlier research that focused on the basic physiology, development and allocation of biomass in vines. Previous research has also examined vineyard-level carbon at the landscape level with coarser estimates of the absolute C storage capacity of vines of different ages, as well as the relative contribution of vines and woody biomass in natural vegetation in mixed vineyard-wildland landscapes. The combination of findings from those studies, together with the more precise and complete carbon-by-vine structure assessment provided here, mean that managers now have access to methods and analytical tools that allow precise and detailed C estimates from the individual vine to whole-farm scales. As carbon accounting in vineyard landscapes becomes more sophisticated, widespread and economically relevant, such vineyard-level analyses will become increasingly important for informing management decisions. The greater vine-level measuring precision that this study affords should also translate into improved scaled-up C assessments . In California alone, for example, there are more than 230,000 ha are planted in vines. Given that for many, if not most of those hectares, the exact number of individual vines is known, it is easy to see how improvements in vine-level measuring accuracy can have benefits from the individual farmer to the entire sector.

Increased wind speed resulted in higher sensible heat losses and, therefore, berry temperatures closer to air temperature, specifically in sparse canopies . The wider row spacing in open canopies , besides providing less wind resistance, also allowed more heating of the ground and air which resulted in higher sensible heat transfer. The greater sensible heat losses in Unilateral compared to Goblet could be explained by the proximity of the Goblet clusters to the adjacent terrace slope, which has the potential for very large temperature variation that greatly affected the sensible heat fluxes. As expected, the cluster heat storage tended to be negative in the morning as the berries began to rapidly warm, and positive in the afternoon while generally cooling and releasing heat .The time series of measured and simulated berry temperature were compared graphically for east- and west-facing clusters in order to qualitatively assess model performance . Graphical results indicated good qualitative agreement between measured and modeled diurnal berry temperature variation at each site. At night time or when berries were in the shade, modeled and measured temperatures closely matched the air temperature. During intermittent periods of solar exposure, round plant pot the model was able to accurately replicate both the magnitude and duration of temperature increases over ambient.

There were a few brief periods, such as in the Unilateral vineyard, in which the timing between the measured and modeled transition from sunlit to shaded conditions lagged by about an hour. It is likely that the observed discrepancies could be explained by slight inaccuracies in the exact position of each berry and leaf. Small errors in the geometric model can translate into large errors in absorbed radiation and berry temperature during periods of sun-shade transition. The statistical error measures describing agreement between measured and modeled time series shown in Fig. 3.6 are summarized in Table 3.4. Quantitative agreement between measured and modeled berry temperature was excellent, with R2 between 0.94 and 0.97, index of agreement between 0.98 and 0.99, and NRMSE between 4.6% and 8.5%. Thus, while there could be brief periods of large error in predicted temperature at any instant when there were rapid transitions between sun and shade, their effect on daily averaged errors were relatively small.The different plant geometries and row spacing also influenced the berry heat storage and, therefore, the variability in berry temperature . Overall, including the heat storage term in the energy balance equation reduced the error of the temperature fluctuations. With no heat storage, the temperature increased or decreased too quickly, typically leading to over- or under-shooting of the berry temperature, which tended to increase model errors .The experimental data collected in this study corresponded to four field sites with different climatic and geographic conditions, and vineyard designs. The average within-canopy ambient microclimate is driven both by the local weather/climate at the site and by the canopy architecture.While it is difficult to directly compare the two Davis experiments because they were conducted during different years, the two Napa plots experienced virtually the same weather conditions and thus differences are likely to be dominated by canopy architecture.

The primary architectural differences between the Goblet and Unilateral plots were that the row spacing in Goblet was much smaller, and berries were in general much closer to the ground. This tighter row spacing and overall denser canopy led to an expected trend of lower wind speeds, more humid air, and cooler air temperatures on average. The ambient microclimate conditions have important implications for average berry temperatures because when there is minimal or no solar heating, such as at night or when the berries are in the shade, the berry temperature is nearly equal to the air temperature. Since berries spend the majority of their time with temperature near the air temperature, this period will dominate the overall average temperature of the berry. Accordingly, prior work measuring apple fruit temperature found that the long-term average fruit temperature was very close to the air temperature, although there could be large deviations from the air temperature at any instant. The differences in vineyard design not only created variability in ambient microclimate, but also introduced considerable temporal and spatial variability in berry temperature. Due to the predominantly north-south row orientation, there were often large differences between the exposed east- and west-facing clusters at any instant in time. Exposure for west-facing clusters coincided with warmer ambient afternoon temperatures, which meant that the average and maximum temperatures of west-facing clusters was typically higher than for east-facing clusters. The substantial asymmetry in temperature accumulation in north-south oriented vineyards is well-known, and has given rise to strategies based on oblique row angles aimed at achieving more even heating between both sides of the row.

Of the different variables explored, the berry temperature was also likely to be influenced by differences in wind speed created by the different vineyard geometries. The wider row spacing in open canopies provided less wind resistance and higher wind speeds that increased sensible heat losses. As observed in Unilateral compared to Goblet, the higher sensible heat losses resulted in fully-exposed berry temperatures closer to air temperature. The proximity of the clusters to the adjacent terrace slope in Goblet may have also increased berry temperatures since the ground has the potential to have high deviations in surface temperature relative to air temperature. The duration and temporal pattern of berry exposure could vary considerably depending on specifics of the berry position. Except for in the Wye vineyard, there were rarely periods in which all berries on a given side of the vine were at a similar temperature . Thus, depending on the horizontal or vertical position of the berry, and random positioning of neighboring leaves, there could be significant variability in berry temperature even on the same side of the vine.Helios simulates complex interactions between the environment and different parts of the vine from ambient weather variables that are not particularly difficult to measure, thereby making it possible to evaluate the applicability of the model at other spatial and temporal scales. Because of the spatially-explicit nature of the plant microclimate model used in this work, it was possible to resolve average differences in berry temperature due to vineyard geometry. Previous models have assumed that the berry temperature is equal to the air temperature, or used simple heuristic rules to represent the mean effect of the vines. The ability to represent berry temperature deviations from the ambient air temperature is likely important for processes that are sensitive to intermittent periods of high temperature, such as chemical composition or berry burn. Simple heuristic models are unlikely to be useful in evaluating the effects of different trellis systems, particularly systems with complex geometries such as Wye. The results of the present study showed significant differences in spatial and temporal patterns in berry temperature between trellis systems, which were well-replicated by the spatially explicit model used for prediction. The model formulation used in this work explicitly represented berry heat storage, and also compared the modeled result when berry heat storage was completely removed. As expected, removing berry heat storage resulted in much larger temporal fluctuations in response to high variability in ambient microclimate. Although inclusion of berry heat storage had a modest impact on average error metrics , it did provide a noticeable reduction in temperature variability when berries were exposed to the sun. The stabilizing effect of berry heat storage also decreased maximum berry temperatures significantly.A limitation of the proposed model is that it does not include the effect of rainfall or a wet canopy on berry temperature. However, round garden pot most quality wines are produced in regions with little average rainfall during the period of berry development. The model also did not explicitly represent the 3D variation of temperature and associated heat within the fruit as has been done in the model developed by Saudreau et al. and Saudreau et al for apple. However, validation results indicated that such detail was not necessary to achieve excellent agreement with measured temperatures, but rather an average exponential dampening of temperature fluctuations with appropriate time constant was sufficient. Another limitation of this study was that currently the model does not predict 3D spatial variations in wind speed, air temperature, or relative humidity, rather, these quantities were measured near the fruit clusters and used to drive the model.

If within-canopy microclimate was not available, it could be necessary to implement a canopy-scale energy and momentum transport model. Previous studies have shown that grape berry metabolism is sensitive to changes in both daily average temperatures and the magnitude of diurnal temperature fluctuations, therefore, advances in our understanding of the berry temperature fluctuations might help develop novel strategies to obtain the desired grape quality. The validation exercise in this work focused specifically on berry temperature from post-veraison to harvest. In future studies, the model could be modified to include latent heat fluxes and be validated to estimate berry temperature during ripening when berry evaporation may be significant and radiative properties of the berries likely differs. In addition to evaluating strategies for mitigating excessive berry temperatures, the model developed in this work could be used on the macro-scale to predict daily berry temperature fluctuations in different regions, such as hilly or mountainous areas and/or areas with arid continental weather subject to dramatic temperature fluctuations. The model could also be coupled with epidemiological and physiological models to study the effect of the spatial and temporal temperature variations on disease incidence or on physiological processes that determine grape yield and quality. Recent increases in average air temperatures and heat wave intensity can present challenges in maintaining grape productivity and quality. As a result, growers are exploring approaches to protect berries from excessive temperatures, however, they can be costly and time-consuming to evaluate experimentally and results may not be generalizable. In this work, we developed and evaluated a new 3D model that can predict metrics related to berry temperature and light interception in response to varying vineyard architecture, topography, and shade cloth density. The resulting modeling tool was applied to better understand and evaluate a range of potential vineyard design and management practices for mitigation of elevated berry temperatures in vertically-trained grapevines. Model validation showed close agreement between predicted and measured temperature dynamics, which responded appropriately to the application of shade cloth. In a simulation experiment, row spacing, row orientation, slope grade and aspect, and shade cloth density were varied in order to evaluate their effect on berry and canopy light interception, berry temperature spikes, and integrated berry heat accumulation. On flat terrain, NE-SW row orientation provided the best compromise of berry light and temperature balance between opposing vine faces while avoiding excessive berry temperatures, while N-S rows provided good daily symmetry but had risk of high afternoon berry temperatures. The efficacy of shade cloth in mitigating excessive temperatures depended strongly on all variables considered. Slopes with southern or western exposure increased imbalance and risk of high berry temperatures, which in some cases could not be well-managed by shade cloth. Overall, the modeling tool appears capable of providing quantitative guidance for vineyard design and management where excessive berry temperatures are a concern.Climate models predict that greenhouse gases will increase global average ambient temperatures by approximately 1 and 3◦C by 2030 and 2100, respectively, in addition to an increase in the frequency, duration and severity of heat waves, particularly in many wine grape growing regions. Elevated temperatures differentially affect rates of grape berry sugar accumulation and phenolic compound development, which can lead to trade-offs in harvest timing that can ultimately result in a reduction in overall grape quality. In Oakville, CA, Mart´ınez-Luscher et al. ¨ reported that elevated temperatures for grape clusters result in unbalanced wines with higher pH and lower levels of anthocyanins. Other research conducted in Murrumbidgee, Australia reported that temperatures exceeding 40◦C resulted in delayed ripening and caused berry sunburn. High ambient air temperatures can exacerbate problems created by excessive berry solar exposure due to the reduction of convective cooling. These high temperatures due to direct sunlight can result in berry cellular damage within a few minutes, while moderately high temperatures can result in injuries or death after long exposure. Grape growers have started to implement practices that modify vineyard microclimate in the short and long term to cope with elevated temperatures.

Proanthocyanidins are found in both the skin and seeds of grape berries . Tannin synthesis in the grape berry starts at flowering, continues in the early stages of grape development, and reaches its maximum around veraison . It then decreases throughout ripening due to a reduction in the extractability of tannins related to their interactions with cell wall components, rather than a decrease related to degradation . The effect of high temperatures on skin and seed tannins have shown inconsistent results across different studies. Cohen et al., found a linear relationship between the increase of skin tannin content and heat accumulation during phase I of grape development. However, Gouot et al., found an increase of total skin tannin concentration in vines exposed to short periods of heat stress before veraison, but found no differences in skin tannin concentration and content at maturity. Studies where heat was applied after veraison have shown no effect on tannin levels, which could be associated with the stop of tannin synthesis after this point in development . Lastly, Bonada et al., conducted a field experiment where vines were exposed to elevated temperatures throughout the entire growing season and found a decrease in total tannin content and concentration at maturity. This was mainly related to a decrease of seed tannins while skin tannins remained unresponsive to elevated temperatures. The different experimental conditions as well as differences in heat treatment design and time of application could be possible explanations for the discrepancies of these findings, as well as whether concentration or content of tannins was studied. Flavonols, anthocyanins, large plastic planting pots and flavan-3-ols are derived from the same precursors and are produced from the flavonoid biosynthetic pathway .

These precursors are derived from the Shikimate and phenylpropanoid pathways. Each step of these pathways are catalyzed by specific enzyme families. Flavonoid enzymes include flavone synthase , flavanone-3ß-hydroxylase , and flavonol synthase . Two enzymes, flavonoid-3’-hydroxylase and flavonoid-3’-5’-hydroxylase , are particularly important because they catalyze the reactions that form di- and tri-hydroxylated flavonoids from monohydroxylated precursors. The genes that code for F3’H and F3’5’H are expressed in the berry skin and contribute to the production of di- and tri-hydroxylated flavonols, anthocyanins, cyanidins, and delphinidin derivatives . The main enzymes for flavan-3-ol production are anthocyanidin reductase and leucoanthocyanidin reductase . However, the enzymes involved in producing proanthocyanidins are unknown. The enzyme that converts anthocyanidins to anthocyanins is UDP-glucose flavonoid-3-O-glucosyltransferase. It is also important to note the MYB transcription factors that are involved in the regulation of the phenylpropanoid pathway. MYBF1 regulates FLS for flavonol production. MYBA1&2 and MYB4 regulate UFGT for anthocyanin synthesis, with MYBA1&2 also being involved in several other steps in the pathway . The effects of high temperatures on the phenylpropanoid and flavonoid pathways is variable, and dependent upon the phenological stage during which heat events occur. Veraison is the most sensitive stage for anthocyanins, while flowering is the most sensitive stage for tannins . Although it has been widely reported that high temperatures impact anthocyanin synthesis, gene expression does not consistently reflect concentration.

A study done by Mori et al. on the variety Darkridge showed that high night temperature resulted in lower anthocyanin concentration due to a down regulation of genes including F3’H and UFGT. Similar results were seen in Kyoho grapes in that high day and night temperatures down-regulated UFGT . However, when the berries were exposed to high temperatures only at night, there was an initial decrease then sudden increase in UFGT activity during ripening. In contrast, a study done on Cabernet Sauvignon showed that UFGT was not strongly down-regulated in grapes that were exposed to high temperatures . Studies show that the effects of high temperatures on the expression of MYB transcription factors remains inconsistent, particularly with MYBA1. Some studies have shown that the expression of MYBA1 was unaffected by high temperatures , whereas other studies showed an extreme down-regulation of this transcription factor . Currently, there is a lack of published research that investigates the potential effects of HWs on berry temperature. While there have been studies published that look at how elevated temperatures affect berry development, primary metabolism, and secondary metabolism, they did not collect data measuring temperature of the berries themselves. For example, in a study done by Cohen et al. , individual cluster temperatures were manipulated to assess the impact of temperature on phenolic metabolism. While this study provided insight to the direct effects of high temperatures, it failed to show whether heat events result in higher berry temperature under different irrigation regimes, and if so, to what extent. The objective of this study was to evaluate the impact that different irrigation practices have on berry phenolics and gene expression carried out prior to and during HWs in a commercial vineyard of Cabernet Sauvignon. The results from this study provide a better understanding of how irrigation during heat events can help mitigate the effects of extreme temperatures and lead to more efficient water use.

In addition, by studying how HWs and irrigation practices influence the production of metabolites in the berry at the chemical and molecular levels provides the wine industry new knowledge that can be used to direct future efforts at preserving berry and wine quality under climate change conditions. In this experiment, a HW was defined as three consecutive days with maximum temperatures at or above 38 °C . Rather than creating artificial HWs with a heating system, this study relied on the occurrence of natural HWs. There were four HWs during the 2020 growing season, and there were two HWs during the 2021 growing season. Differential irrigation treatments were applied when HWs occurred and started one or two days before each HW and continued until the last day of the HW. There were three irrigation treatments: a baseline, which was exposed to deficit irrigation and held at 60% ET, a second treatment where irrigation was double the baseline , and a third treatment where irrigation was triple the baseline . In 2021, the irrigation treatments were adjusted in order to fine tune the amount of water used to see if less water could be used while maintaining the positive aspects of increased irrigation during HWs. The baseline treatment stayed the same at 60% ET, the second treatment was 1.5x baseline , and the third treatment was 2x baseline . Four pixels per treatment were randomly selected and distributed along the site using the VRDI system to provide differential irrigation to the individual plots. ET was estimated throughout the season using Landsat data, normalized difference vegetation index and crop coefficient. Variations in pre-treatment irrigation were implemented at the beginning of the growing season on the plots to even out vigor based on NDVI and thermal imaging due to the heterogeneous soil profile of the site. After, differences in irrigation schedules were based completely on implemented treatmentsBerry temperature was measured using 0.076 mm diameter type ‘E’ thermocouples . There were a total of 20 thermocouples placed in individual berries within three of the treatment blocks. The thermocouples were inserted into the center of the berries in exposed clusters facing the east and west side of the vine, and at each side of the vine 4 thermocouples were placed in different berries within the cluster. Because berries could develop necrosis from being punctured by the thermocouple, thermocouples were relocated to adjacent exposed berries at least every 12 days to maintain relatively fresh conditions . A subset of grape samples were stored at -20 °C for phenolic extraction. Three sets of sixty berries were weighed and volume occupied in water was recorded using a graduated cylinder.Skins were prepared for extraction by separating pulp and seed by hand. The skins were homogenized using a T25 digital ULTRA-TURRAX and S 25 N-18 G Dispersing tool. The skins were homogenized for one minute at 14 speed x 1000 rpm with 100 mL of a 66% acetone and transferred to an opaque polypropylene jar. The jar’s head space was filled with nitrogen gas, closed with a screw cap lid, black plastic planting pots and sealed with parafilm. The skins were extracted for 24 hours on a orbital shaker . The next day, samples were centrifuged for 10 minutes at 10,000 rpm. Samples were then poured through a Buchner funnel into a Buchner flask and filtered through Whatman filter paper with a pore size of 1.

Each filtered sample was transferred to a round-bottom flask and put onto the rotovap for 10 minutes with the water bath at 33 °C. Acetone was removed under reduced pressure. The extracts were brought back to 50 mL with milli-q water, and volume was recorded using a graduated cylinder. The samples were transferredto centrifuge tubes and stored at -20 °C until analysis. The next day, the samples were filtered, and acetone was separated from the solution using a rotovap. The samples stayed on the rotovap for 10 minutes with the water bath at 33 °C. The concentrated extracts were diluted with milli-q water, and volume was recorded using a graduated cylinder. The samples were transferred to falcon tubes and stored at -20 °C until analysis. Triplicate grape extracts were analyzed by methyl cellulose precipitation, which is the method used for analyzing tannin in extracts and wine, as previously published . Briefly, 25 µL of extraction sample was placed into 1200 µL deep well plates and combined with 300 µL of 0.04% methyl cellulose  solution or water , and mixed on an Thermomixer-C for 5 minutes at 1500 RPM and left to stand for 3 minutes. Following the mixing, 200 µL of saturated ammonium sulfate was added to the wells to prevent the re-release of proanthocyanidin material into solution following precipitation. Water was then added to the wells and again it was mixed for 5 minutes. The deep well plate was then allowed to stand for 10 minutes before being centrifuged for 5 minutes at 2,272 × g . Both the treated and control samples were taken and placed in a 96 half-area well plate . -Epicatechin was used as a quantitative standard. Proanthocyanidin quantification was conducted by calculating Δ280 nm with the linear regression from an -epicatechin standard curve. The samples were analyzed on the SpectraMax iD3 microplate reader. Endpoint analysis was at 280 nm, and a pathway correction made up for volume differences. Berry temperature was recorded across the August 2020 and September 2020 heat waves . Berry temperatures from 60% ET treatment were significantly different from the 120% ET and 180% ET treatments for the pre-HW date of August 13th . There were no significant differences in berry temperature between the three treatments for the August 2020 HW and post-HW dates. For the August 13th pre-HW date, peak berry temperature occurred at 13:00 hours for the 180% ET treatment. For the HW date, peak berry temperature was at 15:00 hours for the 120% ET treatment. For the post-HW date, peak berry temperature was at 17:00 hours for the 60% ET treatment. There were no significant differences among the three treatments during the September 2020 HW . For the pre-HW date, peak berry temperature was at 15:00 hours for the 60% ET treatment. Similarly, for the HW and post-HW dates, peak berry temperature was at 15:00 hours for the 180% ET treatment. Berries in the August 2020 HW consistently reached higher temperatures than berries in the September 2020 HW, which may be due to differences in the extremity of the respective HWs. Anthocyanins in both growing seasons were measured from pre-veraison until commercial harvest. As seen in Figure 4, in the 2020 growing season, the 60% ET treatment started out with the lowest total anthocyanin concentration and continued throughout the rest of the season. During HW3 and HW4, we see significant differences between the treatments. At harvest, there were no differences between the 120% ET and 180% ET treatments, but both treatments had significantly higher anthocyanin concentrations than the 60% ET treatment, suggesting that the additional water prior to the heat waves had mitigated the loss of anthocyanin material. Looking at Figure 4, again in 2021, the 60% ET treatment had consistently lower anthocyanin concentrations throughout the season. Unlike the 2020 growing season, the 60% ET treatment remained significantly different from the other two treatments starting at August 17th until close to harvest. However, at harvest, there were no significant differences between the three treatments.

What people say they prefer and what they actually do may, of course, be quite different. In order to get a sense of the extent to which people actually exercise the label preferences they indicated in the marketplace, we asked about their purchase patterns of foods with these labels. We asked specifically about fair trade, organic, and local, first defining the terms . Respondents were asked to check one of the following options regarding their purchasing habits: never, at least once a year, at least monthly, at least weekly, and don’t know. Respondents claimed to purchase these products quite often . At least 50% of the respondents reported purchasing products with one of these labels at least monthly or more often. Organic is the most frequently purchased item, with 42% buying such products at least weekly, and 68% at least monthly. Local products were the next most frequently purchased, with 63% purchasing them at least monthly. Almost 25% of people purchase fair trade at least weekly, and 52% at least monthly. A large number of respondents stated that they did not know whether they have purchased products with these labels. Almost a third of the respondents didn’t know whether they had purchased food that was fair trade and 27% didn’t know whether they had purchased local foods. And, even though the organic label is fairly well established, 16% of the people said they didn’t know whether they had purchased organic food. This information implies that either people don’t know enough about the labels, or that they just don’t look for them when they purchase their food. Considering that organic foods are fairly well known, plastic pot plant containers it is likely safe to assume that the high numbers of those who didn’t know whether they had purchased fair trade may be partially due to lack of information about the label. Thus, it would be useful to have more education about the Fair Trade label.

The large percentage of those who didn’t know whether they had purchased local is likely due to the fact that there isn’t a standard label for such products. For example, one of the factors that makes America’s relatively “cheap” food supply possible is low labor costs; the wages of workers in the food industry are often at poverty or below-poverty levels. To get at the criterion of social justice, we asked if people would be willing to pay more for their food if it meant better conditions for workers, and a living wage. In order to gauge this interest, survey respondents were asked whether they would be willing to pay more for a single product, strawberries. We chose strawberries because there had been a United Farm Workers campaign in the region to inform people about how much paying just five cents more for a pint of strawberries would do to improve wages and working conditions for strawberry farm workers. We asked survey respondents how much more they would be willing to pay for a pint of strawberries that guarantees a living wage and safe working conditions for farm workers. Survey respondents were randomly assigned 1 of 4 questions, asking if they would be willing to pay 5 cents, 25 cents, 50 cents or $1.50 more for strawberries that otherwise would cost $1.50 . Results indicate that nearly all respondents would be willing to pay at least 5 cents more and most people state they would pay significantly more than that ; 85% are willing to pay 25 cents more , 74% are willing to pay 50 cents more , and close to 50% claimed willingness to pay twice as much for a pint of strawberries. We posed a second “willingness to pay” question to meal-plan holders. We asked, “Would you be willing to pay more for your meal plan if the food had been produced in a socially just manner—for example, where workers have safe working conditions and receive a living wage ?” 

A third of meal-plan holders were willing to pay more for socially just food, a quarter were not, and the remainder were unsure . Why are there so few people willing to pay more in the dining commons than for a pint of strawberries? First, the lack of interest shown here is likely at least partially an artifact of the way the question was asked. Unlike the strawberry question, the meal plan holders were not asked a specific amount more that they might be willing to pay—which likely led to the large “unsure” numbers. We were not able to give a more specific amount because it is not clear how much a meal costs . Second, meal plan holders may just be less likely to pay more in general. From comparing how meal plan holders and all others answered the strawberry question, meal plan holders were somewhat less likely to pay more for the strawberries than the others . As noted, our survey results show that one-third of meal plan holders indicated a willingness to pay more for a meal plan for food produced in a socially just manner, and about one quarter were opposed to such a cost increase. Further research, with more specific scenarios, would be needed to get a better idea of the number of people that might really be willing to pay more. When considering these results, it is important to keep in mind that people don’t always do what they say they will—that they are more likely to respond positively on a survey than they may in practice. People often take many factors into account when making purchases, not just one. However, even given a likely inflated positive response, there appears to be significant support for paying more for socially just food.We asked respondents to indicate their preferences for how they would like to learn about the food system. Ten options were listed on the survey and respondents were asked to check four of them . As is shown in table 7, respondents’ preferred media for learning about their food were product labels and information available where they purchase or eat their food . Print media—e.g., newspapers, magazines, articles, and books—and web pages were the next most preferred at 48% and 47%, respectively. Other methods—tours, audiovisual media, talking to farmer/seller, and lectures—were preferred by less than 25% of respondents. Study groups garnered the least interest at 3%. Providing food system education in the dining halls, campus restaurants, and at coffee carts will likely be the most appreciated and most effective method for sharing information with a broad audience.

This study shows that food issues are important to a campus community, particularly regarding concerns for the environment and for people. Survey respondents showed high levels of interest in purchasing food produced in an environmentally sound and socially just manner. Key points from this study include – • There is significant interest in campus food that is nutritious, safe, supports workers, and is environmentally sound; interest in local food and GE-free food is lower. • People are interested in sustainably produced food and a majority of people already purchase food with labels based on these criteria. • Many people are willing to pay more for food that meets social justice criteria. • A campus community is likely to be receptive to education and discussion about food-system issues. • Since nutrition and food safety were of great importance to people, framing discussions of food-system issues in terms of health will meet people’s needs as well as capture their attention for education on other food-system issues, such as working conditions and environment. It would not be appropriate to extrapolate too much from a study of one campus; results from our 2007 national student survey will provide more comprehensive data. In the meantime, the results of the UC Santa Cruz study support the idea that colleges and universities are excellent choices for developing farm-to-institution programs and for popular education on food-system issues. In plants, a fruit is the seed-containing section, which is formed from the ovary after flowering. Fruits have their vivid colors due to the presence of phytochemicals as pigments, large plastic gardening pots which are natural compounds that protect against threats and insults such as insects and ultraviolet sunlight. Bright colors of fruits also attract animals and human beings for seed dispersing purposes.1 The belief of using fruits as traditional medicine exist in many cultures worldwide. For instance, cocoa beans and blueberries have been used traditionally as therapies among indigenous people in North America. The fruit, leaves, seed, and bark of the mango plant have been used as traditional medicine in Southeast Asia, Oceania, Africa, and Central America. Goji berries have been used as traditional Chinese medicine for two thousand years. Phytochemicals can be classified primarily as terpenoids, phenolics, alkaloids, nitrogencontaining plant constituents, and organosulfur compounds. Examples of major phytochemical groups that are abundant from dietary sources and related to human health include carotenoids and polyphenols. Carotenoids are a type of terpenoid. Carotenoids can be classified as carotenes and xanthophylls.4 Phenolics can be classified as phenolic acids and polyphenols.

Two primary subclasses of phenolic acids are hydroxybenzoic acid and hydroxycinnamic acid. Polyphenols include flavonoids, tannins, stilbenes, lignans, and xanthones. As one of the most studied categories of polyphenols, subclasses of flavonoids can be categorized to flavanones, flavones, anthocyanins, flavanols , chalcones, flavonols, and isoflavonoids. Among the thousands of phytochemicals that have been identified in plants, both health promoting and toxic compounds exist. For instance, some tannins decreased the activity of digestive enzymes or the bio-availability of protein or minerals and have been considered as anti-nutrients. Phytochemicals that exist in plant-based dietary sources and have value in human health maintenance and prevention of diseases are defined as phytonutrients. Fruits, vegetables, legumes, spices, nuts, wine, cocoa, tea, and olive oil are examples of foods rich in bio-active phytonutrients. The consumption of these dietary components has been related to decreased risk of developing chronic diseases, including cardiovascular diseases , age-related eye diseases, type II diabetes, cancers, and all-cause mortality. Observational studies also have reported that the total dietary polyphenol intake was inversely associated with the risk of hypertension, hypercholesterolemia, and cardiovascular events. Polyphenols under different categories may play various roles in reducing CVD risk. In the United States, the estimated flavonoid intake is 345 mg/day, with flavanols as the most abundant source. The three most consumed flavanols are catechin, epicatechin, and their polymers. Subanalyses of a cohort study indicated that dietary intakes of flavanols along with lignans, dihydrochalcones, and hydroxybenzoic acids showed a stronger inverse association with the risk of overall CVD events than other phenolic compounds.16 Another cohort study reported that the dietary intakes of anthocyanins, dihydrochalcones, dihydroflavonols, proanthocyanidins, catechins, flavonols, hydroxybenzoic acids, and stilbenes were significantly associated with decreased risks of total CVD. Blueberries and cranberries contain high amount of anthocyanin and proanthocyanidin, respectively, with moderate concentration of flavonoids. Cocoa is rich in flavanols, especially epicatechin and catechin. Mango, as the fourth leading fruit crop worldwide, is high in carotenoids, phenolic acids, and mangiferin, a polyphenol classified as a xanthonoid. Carotenes exist in dietary sources primarily as α-carotene, β-carotene, and lycopene. Major xanthophylls that exist in dietary sources include lutein , zeaxanthin , and β-cryptoxanthin. Epidemiological studies report inconsistent results on the relationship between dietary L and Z intakes and the risk of age-related macular degeneration. However, clinical studies have shown that the supplementation of L and Z was able to increase the level of these compounds in the retina, suggesting their protection against age-related macular degeneration . A major dietary source of L and particularly of Z is goji berry, which also have other in carotenoids, as well as phenolic acids, and flavonoids. While many examples of fruits used traditionally for health promotion exist, this literature review focuses on the evidence of mango, cocoa, blueberries, and cranberries in cardiovascular health, and goji berries in eye health. The application of modern scientific methods to assess traditional remedies is important because evidence-based data is necessary to transfer historical stories and ancient wisdom to contemporary life and advancement of health and human performance.Cocoa is the dried and fully fermented product obtained from the seeds of Theobroma cacao L. and is the main ingredient in chocolate products.

Each vessel in the body has different properties therefore when a stent is being designed, the geometry, structure, and mechanics of the target vessel should be considered. Several groups have examined the fluid dynamics governing blood flow through stented arteries. These studies concluded circular shape of the vessel lumen will optimize fluid flow characteristics at the blood/tissue interface, reducing regions of turbulence and/or stagnation in the immediate vicinity of stent struts. Laminar flow within the lumen of more circular stented arteries may decrease the platelet and inflammatory cell adhesion and activation, therefore, reducing neointimal hyperplasia. Although there was not a significant difference of stenosis between stents with five apices versus stents with six apices but Garasic et al., argued altering lumen shape by increasing the number of struts per cross section from 8 to 12 was associated with a 50% to 60% drop in mural thrombus burden after 3 days and a 2-fold reduction in neointimal thickening after 28 days in rabbit arteries. Therefore, more strut numbers and regularity of strut distribution provides a more circular vascular lumen which is associated with a smoother, more homogeneous arteriographic contour and more beneficial for the performance of a stent and needs to be considered for the future novel stent designs.Although this study was the first study to examine the effects of self-expanding stents on growth vessels, square plastic plant pots it was not enough for the assessment of complete aneurysm formation and full stent expansion in the arteries.

Longer studies are needed to assess for late aneurysm formation or erosion as well as stenosis. While this data set shows growth, it is not able to determine the extent of the stented vessel expansion. Will these stents ultimately expand to their full potential? If not, how close will they get. Future studies should consider more animals, longer implant times and should examine lower-radial force stents as well as various stent geometries and stent placement in different vessels. Stents that can grow with a small but rapidly growing artery can be designed and could be ideal for several pediatric applications. Despite obvious medial injury in some cases, all stents in this study grew with and beyond the native vessel’s growth without development of stenoses, aneurysms or dissections. Although this data set only includes 3- and 6-month pathology, it is likely to be useful in the design of the ideal set of pediatric growth stents. Agriculture is a key human activity in terms of food production, economic importance and impact on the global carbon cycle. As the human population heads toward 9 billion or beyond by 2050, there is an acute need to balance agricultural output with its impact on the environment, especially in terms of greenhouse gas production. An evolving set of tools, approaches and metrics are being employed under the term “climate smart agriculture” to help—from small and industrial scale growers to local and national policy setters—develop techniques at all levels and find solutions that strike that production-environment balance and promote various ecosystem services. California epitomizes the agriculture-climate challenge, as well as its opportunities.

As the United States’ largest agricultural producing state agriculture also accounted for approximately 8% of California’s greenhouse gas emissions statewide for the period 2000–2013. At the same time, California is at the forefront of innovative approaches to CSA . Given the state’s Mediterranean climate, part of an integrated CSA strategy will likely include perennial crops, such as winegrapes, that have a high market value and store C long term in woody biomass. Economically, wine production and retail represents an important contribution to California’s economy, generating $61.5 billion in annual economic impact. In terms of land use, 230,000 ha in California are managed for wine production, with 4.2 million tons of winegrapes harvested annually with an approximate $3.2 billion farm gate value. This high level of production has come with some environmental costs, however, with degradation of native habitats, impacts to wildlife, and over abstraction of water resources . Although many economic and environmental impacts of wine production systems are actively being quantified, and while there is increasing scientific interest in the carbon footprint of vineyard management activities [e.g., 11], efforts to quantify C capture and storage in annual and perennial biomass remain less well-examined. Studies from Mediterranean climates have focused mostly on C cycle processes in annual agroecosystems or natural systems. Related studies have investigated sources of GHGs , on-site energy balance, water use and potential impacts of climate change on productivity and the distribution of grape production. The perennial nature and extent of vineyard agroecosystems have brought increasing interest from growers and the public sector to reduce the GHG footprint associated with wine production. The ongoing development of carbon accounting protocols within the international wine industry reflects the increased attention that industry and consumers are putting on GHG emissions and offsets. In principle, an easy-to-use, wine industry specific, GHG protocol would measure the carbon footprints of winery and vineyard operations of all sizes.

However, such footprint assessment protocols remain poorly parameterized, especially those requiring time-consuming empirical methods. Data collected from the field, such as vine biomass, cover crop biomass, and soil carbon storage capacity are difficult to obtain and remain sparse, and thus limit the further development of carbon accounting in the wine sector. Simple yet accurate methods are needed to allow vineyard managers to measure C stocks in situ and thereby better parameterize carbon accounting protocols. Not only would removing this data bottleneck encourage broader participation in such activities, it would also provide a reliable means to reward climate smart agriculture.Building on research that has used empirical data to compare soil and above ground C stocks in vineyards and adjacent oak woodlands in California, this study sought to estimate the C composition of a vine, including the relative contributions of its component parts . By identifying the allometric relationships among trunk diameter, plant height, and other vine dimensions, growers could utilize a reliable mechanism for translating vine architecture and biomass into C estimates. In both natural and agricultural ecosystems, several studies have been performed using allometric equations in order to estimate above ground biomass to assess potential for C sequestration. For example, functional relationships between the ground-measured Lorey’s height and above ground biomass were derived from allometric equations in forests throughout the tropics. Similarly, functional relationships have been found in tropical agriculture for above ground, below ground, and field margin biomass and C. In the vineyard setting, however, horticultural intervention and annual pruning constrain the size and shape of vines making existing allometric relationships less meaningful, though it is likely that simple physical measurements could readily estimate above ground biomass. To date, most studies on C sequestration in vineyards have been focused on soil C as sinks and some attempts to quantify biomass C stocks have been carried out in both agricultural and natural systems. In vineyards, studies in California in the late 1990s have reported net primary productivity or total biomass values between 550 g C m−2 and 1100 g C m−2. In terms of spatial distribution, some data of standing biomass collected by Kroodsma et al. from companies that remove trees and vines in California yielded values of 1.0–1.3 Mg C ha−1 year−1 woody C for nuts and stone fruit species, square pot plastic and 0.2–0.4 Mg C ha−1 year−1 for vineyards. It has been reported that mature California orchard crops allocate, on average, one third of their NPP to the harvested portion and mature vines 35–50% of the current year’s production to grape clusters. Pruning weight has also been quantified by two direct measurements which estimated 2.5 Mg of pruned biomass per ha for both almonds and vineyards. The incorporation of trees or shrubs in agroforestry systems can increase the amount of carbon sequestered compared to a monoculture field of crop plants or pasture. Additional forest planting would be needed to offset current net annual loss of above ground C, representing an opportunity for viticulture to incorporate the surrounding woodlands into the system. A study assessing C storage in California vineyards found that on average, surrounding forested wild lands had 12 times more above ground woody C than vineyards and even the largest vines had only about one-fourth of the woody biomass per ha of the adjacent wooded wild lands.The objectives of this study were to: measure standing vine biomass and calculate C stocks in Cabernet Sauvignon vines by field sampling the major biomass fractions ; calculate C fractions in berry clusters to assess C mass that could be returned to the vineyard from the winery in the form of rachis and pomace; determine proportion of perennially sequestered and annually produced C stocks using easy to measure physical vine properties ; and develop allometric relationships to provide growers and land managers with a method to rapidly assess vineyard C stocks.

Lastly, we validate block level estimates of C with volumetric measurements of vine biomass generated during vineyard removal.The study site is located in southern Sacramento County, California, USA , and the vineyard is part of a property annexed into a seasonal floodplain restoration program, which has since removed the levee preventing seasonal flooding. The ensuing vineyard removal allowed destructive sampling for biomass measurements and subsequent C quantification. The vineyard is considered part of the Cosumnes River appellation within the Lodi American Viticultural Area, a region characterized by its Mediterranean climate— cool wet winters and warm dry summers—and by nearby Sacramento-San Joaquin Delta breezes that moderate peak summer temperatures compared to areas north and south of this location. The study site is characterized by a mean summer maximum air temperature of 32 °C, has an annual average precipitation of 90 mm, typically all received as rain from November to April. During summer time, the daily high air temperatures average 24 °C, and daily lows average 10 °C. Winter temperatures range from an average low 5 °C to average high 15 °C. Total heating degree days for the site are approximately 3420 and the frost-free season is approximately 360 days annually. Similar to other vineyards in the Lodi region, the site is situated on an extensive alluvial terrace landform formed by Sierra Nevada outwash with a San Joaquin Series soil . This soil-landform relationship is extensive, covering approximately 160,000 ha across the eastern Central Valley and it is used extensively for winegrape production. The dominant soil texture is clay loam with some sandy clay loam sectors; mean soil C content, based on three characteristic grab samples processed by the UC Davis Analytical Lab, in the upper 8 cm was 1.35% and in the lower 8–15 cm was 1.1% . The vineyard plot consisted of 7.5 ha of Cabernet Sauvignon vines, planted in 1996 at a density of 1631 plants ha−1 with flood irrigation during spring and summer seasons. The vines were trained using a quadrilateral trellis system with two parallel cordons and a modified Double Geneva Curtain structure attached to T-posts . Atypically, these vines were not grafted to root stock, which is used often in the region to modify vigor or limit disease .In Sept.–Oct. of 2011, above ground biomass was measured from 72 vines. The vineyard was divided equally in twelve randomly assigned blocks, and six individual vines from each block were processed into major biomass categories of leaf, fruit, cane and trunk plus cordon . Grape berry clusters were collected in buckets, with fruit separated and weighed fresh in the field. Biomass was transported off site to partially air dry on wire racks and then fully dried in large ventilated ovens. Plant tissues were dried at 60 °C for 48 h and then ground to pass through a 250 μm mesh sieve using a Thomas Wiley® Mini-Mill . Total C in plant tissues was analyzed using a PDZ Europa ANCA-GSL elemental analyzer at the UC Davis Stable Isotope Facility. For cluster and berry C estimations, grape clusters were randomly selected from all repetitions. Berries were removed from cluster rachis. While the berries were frozen, the seeds and skins were separated from the fruit flesh or “pulp”, and combined with the juice . The rachis, skins and seeds were dried in oven and weighed. The pulp was separated from the juice + pulp with vacuum filtration using a pre-weighed Q2 filter paper . The filter paper with pulp was oven dried and weighed to get insoluble solid fraction .

However,leaf petioles analysis of grapes from both vineyards showed considerable differences in nutrient levels, especially in the primary macro-nutrients . During both seasons, the amount of nitrogen in the form of nitrate in LP-V9 was roughly 2 to 3 times higher than the normal levels, in contrast to its counterpart in LP-V7, which slightly accumulated more or less N. Similarly, LP-V9 contained higher percentages of phosphorus and potassium compared to LP-V7 . Conversely, the amounts of secondary macro-nutrients, calcium and magnesium , in LP-V7 were within the normal range but greater than LP-V9, which showed Mg deficiency in the first year only. Regarding the micro-nutrients, their levels were mainly within or around the normal range at both vineyards and during both seasons, with some differences . For example, zinc was slightly higher in LP-V9, especially in the first year. On the contrary, manganese and chlorine were roughly 2 times higher in V7 . Similarly, soil analysis shoed a higher level of nitrogen, potassium and magnesium . However, no significant difference was observed in all other soil macro and micro-nutrients. During the two seasons of the study, we determined the total marketable yield and the number of clusters in both vineyards. Our data revealed a higher yield in V7 compared to V9 in 2016 and 2017, respectively. The lower yield in V9 can likely be attributed to the smaller number of clusters in V9 compared to V7 during 2016 and 2017. To monitor the changes in the biochemical composition of Scarlet Royal berries, V7 and V9 berries were periodically sampled at six time points from veraison until the end of the season . The obtained data showed that berry polyphenols exhibited discernible patterns in both vineyards, most notably during the ripening stage .

Of special interest were the tannin compounds, blueberry box which widely affect organoleptic properties such as astringency and bitterness . Our data showed that berries from both V7 and V9 vineyards maintained lower levels of tannin from veraison up to the middle of August . Subsequently, a significant gradual increment of tannin took place. However, only V9-berries showed consistent accumulation of tannin over the two studied seasons compared to V7-berries, where the significant induction occurred only during the first season. It is worth noting that the levels of tannin were lower in both vineyards during the second year compared to the first season. Nevertheless, they were more pronounced in V9-berries compared to V7-berries, with roughly 2- to 4.5-fold increases by the end of the harvesting time during the two seasons, respectively . The patterns of catechin and quercetin glycosides were inconsistent during both seasons, particularly within V7-berries . During the first year, for instance, the levels of catechin were similar in both vineyards, showing a dramatic increase only by the end of the season . In contrast, during the second year, such induction of catechin was exclusively restricted to V9-berries, starting from time S3 . For quercetin glycosides, V7-berries exhibited significantly higher amounts at early stages during both seasons relative to V9-berries . However, subsequent amounts were comparable in both vineyards during the first season only , but not in the second one, where V7-berries showed a significant drop at the last sample S6 . Interestingly, the levels of quercetin glycosides were roughly equal at the last V9-berries sample between both seasons despite such inconsistency. For total anthocyanins , the levels in early samples were comparable in both vineyards and seasons . Afterwards, their pattern started to vary between V7 and V9 within the same season, as well as from the first season to the second, as the nutrient amounts fluctuated as well . Nevertheless, TAC accumulation was positively correlated with the progress of ripening in V7-berries, but not V9-berries. To further confirm our data, we measured these phenolic compounds for the third time in mid-September of the next year .

Overall, the results showed that the patterns of tannins and TAC were reciprocally inverted between V7-berries and V9-berries as ripening advanced. In addition, both catechin and quercetin glycosides most likely followed the pattern of tannins despite their seasonal fluctuations. To further distinguish V7-berries and V9-berries and assess their astringency development, a panel test was performed using samples at three commercial harvest times . A group of 12 nontechnical panelists scored berry astringency on a scale from 1 to 7, where 1 is extremely low and 7 is extremely high. The panelists were trained using samples from contrasting standard varieties, including Flame Seedless and Crimson as non-astringent and Vintage Red known for its astringent taste . The results showed that V7-berries exhibited lower intensity of astringency compared to V9-berries . As ripening proceeded, astringency levels increased in V9-berries, but decreased in V7-berries. Moreover, we collected samples from clusters with various astringent taste and measured its tannins content. We were able to determine that the threshold level of tannins that causes the Scarlet Royal astringency taste is around 400 mg/L . Taking into account the levels of polyphenol compounds and the taste panel data together , it is evident that astringency development is positively associated with tannins’ accumulation throughout the ripening process of V9-berries. Nevertheless, organoleptic analysis revealed a significant difference in the berries of the two vineyards, particularly in terms of total soluble solids and titratable acidity . Notably, V9 berries exhibited higher titratable acidity and lower total soluble solids, especially in the later stages .

It’s worth noting that the weight of V9 berries is also higher than that of V7 .To better understand the molecular events associated with the induction of tannins and astringency upon ripening, the berry transcriptome profile was analyzed in both V7-berries and V9- berries at the late commercial harvest date . Following the quality and quantity check, extracted RNA from quadruplicate samples was deeply sequenced . Of the 19.7 to 24.4 million high-quality clean reads per replicate, 61.9% to 66.1% were mapped against the V. vinifera transcriptome . Hierarchical clustering of the RNAseq data showed explicit changes in the berry transcriptome profile between V7- berries and V9-berries . Samples were mainly separated along the first component , which was responsible for 97% of the variance, and was definitely associated with the site of cultivation; V7 and V9. In contrast, the second component was trivial, accounting for only 1% of the variance and was probably attributed to experimental error. Such results were expected, as berry samples came from the same cultivar, Scarlet Royal , and the only difference between them was the vineyard locations. To identify the differentially expressed genes in V7- berries and V9-berries at this specific time within the ripening window, the RNAseq data were analyzed using two different Bioconductor packages, DESeq2, and EdgeR . Subsequently, the DEGs with FDR < 0.05 and log2fold change > 1.5 or < –1.5 generated by both pipelines were considered . The pairwise comparison between berry transcriptomes resulted in 2134 DEGs, with 1514 up-regulated and 620 down-regulated . The data manifested the impact of the cultivation site on the transcriptional reprogramming of a large number of genes that ultimately affect berry quality. Most apparently, at the V9 vineyard, where roughly 2.5-fold higher number of berry transcripts were upregulated compared to V7 . Subsequently, the enrichment of Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were analyzed among the up- and down-regulated DEGs using the Vitis vinifera Ensembl GeneID . Among the significantly enriched GO terms, the up-regulated transcripts in V9-berries exhibited high enrichment in the molecular function GO terms for quercetin 3-O-glucosyltransferase activity and quercetin 7-Oglucosyltransferase activity . Additionally, the V9-berries induced DEGs were highly enriched in the biological process GO terms for the jasmonic acid signaling pathway and cellular response , Lphenylalanine metabolic process , L-phenylalanine biosynthetic process , and nitrogen compound metabolic process . Similarly, these DEGs were highly enriched in the KEGG pathways for the biosynthesis of secondary metabolites and phenylpropanoid biosynthesis . On the other hand, the down-regulated transcripts in V9-berries showed substantial augmentation in the MF GO terms for hormone binding , abscisic acid binding , and potassium ion transmembrane transporter activity . Correspondingly, the BP GO terms for hormone-mediated signaling pathway and response , auxin-activated signaling, cellular response, and homeostasis , abscisic acid-activated signaling, response, and cellular response , response to strigolactone , potassium ion transmembrane transport , and potassium ion transport , as well as the KEGG pathways for plant hormone signal transduction , brassinosteroid biosynthesis , blueberry package and carotenoid biosynthesis were highly enriched in the down-regulated genes of V9-berries . Overall, the transcriptome analysis pointed out the substantial changes in transcript abundance that coordinate and reflect the observed induction of tannins/astringency during the maturation and ripening of V9-berries compared to the V7-berries .To elucidate which fundamental processes were altered during tannins/astringency induction within berries, the Weighted Gene CoExpression Network Analysis was applied to construct coexpression networks. Forty-two modules were identified based on pairwise correlations among the 17553 non-lowly expressed genes . Subsequently, the biochemical data from both V7-berries and V9-berries were correlated to the WGCNA modules, and only 2 modules, M21 and M30, displayed substantial correlations with berry polyphenols, containing 5349 and 4559 genes, respectively .

The M21 module was positively linked with TAC , but negatively associated with tannins, catechin, and quercetin glycosides . On the contrary, the M30 module exhibited a positive correlation with tannins, catechin, and quercetin glycosides , but was negatively linked with TAC . The DEGs obtained from the two pipelines were assigned to both M21 and M30, yielding 604 and 1362 genes, respectively . Interestingly, the number of DEGs in each module, M21 and M30, was roughly equal to the down- and upregulated genes, respectively . To identify flavonoids/tannins-related genes that might result in such astringency diversity between V7-berries and V9-berries, hub genes were searched in the DEGs list of both modules . Only 8 hub genes were identified based on their transcript abundances in V9- berries and predicted functions. However, based on our previous work , we found another 11 genes that are significantlyexpressed but with a log2FoldChange less than 1.5, and they were included in our further analysis . The enrichment analysis of GO showed considerable enrichment in the BP GO terms for secondary metabolite biosynthetic process , flavonoid biosynthetic/metabolic process , L-phenylalanine metabolic/ catabolic process , phenylpropanoid metabolic process , phenylpropanoid biosynthetic process , chorismate biosynthetic/metabolic process , cinnamic acid biosynthetic/ metabolic process , anthocyanincontaining compound biosynthetic/metabolic process . The KEGG pathway analysis confirmed the BP GO terms, exhibiting enrichment for the biosynthesis of secondary metabolites , phenylpropanoid biosynthesis , flavonoid biosynthesis , and glutathione metabolism .To precisely elucidate their significance in the tannins/astringency diversity between V7-berries and V9-berries, we studied the expression levels of the 19 hub genes associated with the shikimic and flavonoids pathway. Except for the PAL1_1 gene , the analysis of their relative expression by real-time quantitative PCR showed a significant correlation with the Transcripts Per Million values for genes of interest, validating the transcriptomic data from both V7- and V9-berries . In general, all genes showed higher expression levels in V9-berries compared to V7-berries, but with different degrees of induction. Forinstance, the two genes involved in the shikimic acid pathway, chorismate synthase , and chorismate mutase , showed visibly higher accumulation abundance in V9-berries at the third harvesting time with approximately 6-fold and 3-fold increases, respectively, compared to V7-berries. Similarly, the upstream structural genes in the phenylpropanoids pathway, including phenylalanine ammonia lyase , trans-4- coumarate biosynthesis , and 4-coumaroyl:CoAligase 2 , were significantly induced by approximately 2- to 9-fold in V9-berries. Regarding flavonoids/PAs biosynthesis, chalcone synthase is considered a key enzyme in this pathway, converting p-coumaroyl-CoA to naringenin chalcone, which is later turned into naringenin by chalcone isomerase . Both genes were highly expressed in V9-berries . Naringenin is subsequently converted by flavonoid 3’-monooxygenase to dihydromyricetin and dihydroquercetin, which are further transformed by dihydroflavonol 4-reductase into leucodelphinidin and leucocyanidin, respectively . The expression levels of F3H and DFR also showed a commensurate induction with the upstream genes in V9-berries relative to V7-berries. Subsequently, leucoanthocyanidin dioxygenase and leucoanthocyanidin reductase catalyse the conversion of leucodelphinidin to delphinidin and -gallocatechin, respectively, as well as leucocyanidin to cyanidin and catechin, respectively. These three genes also exhibited a significant increase in V9-berries. Finally, the expression of genes encoding glutathione Stransferases , one of the most essential anthocyanin transporters, was significantly higher in V9-berries compared to V7-berries, with approximately 3- to 9.2-fold changes .

The deviation is almost zero near Ŵ point and begin to have large value at the momentum at which the Berry curvature and the OAM are also about to increase from almost zero value. This provides experimental evidence that the deviation from the median value of INCDs in geometry-A and -B can be interpreted as the Berry curvature contribution. Although the Berry curvature and the OAM continually increase as they approach the K point, the deviation from the median value from CD-ARPES data seems to be almost constant away from the Ŵ point.Let us briefly touch upon the possible incident photon energy dependence in CD-ARPES or the final state effect. This is because one can wonder if the CD-ARPES pattern we obtained is seen only with the particular photon energy and a different photon energy may give us a different result. In such case, changing the photon energy will also change the CD-ARPES pattern and the CD-ARPES may not be related to OAM or the local Berry curvature. We would like to point out that incident photon energy dependent CD-ARPES has been performed on the same material. The results showed that CD-ARPES features related to the local Berry curvature are the same regardless of the photon energy. Even though it was for a different plane of incidence compared to the current one, the photon energy independence of the pattern provides a good reason to believe that the CD-ARPES pattern is proportional to OAM or the local Berry curvature. In some the other systems such as Bi2Te3, PtCoO2 and Au, CD-ARPES results show a sign change. Yet, growing bags those results still show that node lines in CD-ARPES map remain the same except a special resonant channel is involved.

In addition, characteristic patterns of CD-ARPES map cannot be explained without consideration of OAM. Therefore, we argue that the interpretation of the CD-ARPES intensity in this work should be robust although the data was taken only with a single photon energy. CD-ARPES data on 2H-WSe2were taken with the crystal mirror plane set as the experimental mirror plane. Within the experimental constraint, there are two possible experimental geometries. We found that CD-ARPES data for the two geometries are almost opposite to each other near the BZ corners, and nearly the same near the Ŵ point. The experimental observations are well explained by accounting for the Berry curvature contribution to CD-ARPES. The Berry curvature contribution to the INCDs can be quantitatively extracted through an analysis that compares INCDs for the two geometries. Our results provide experimental evidence that the deviation from the median value between the two experimental geometries can be interpreted as the Berry curvature or the OAM. Our work may be applicable to observations of the Berry curvature or the OAM in topological materials, such as Weyl semimetals and Berry curvature dipole materials.Horticultural crops provide 60 percent of total farm revenue in California agriculture, and California provides 37 percent of the horticultural crop value in the United States. Clearly, these industries comprise an important part of the agricultural economy. This study provides a detailed statistical profile of California’s horticultural crop industries at the farm level, based on a survey of specialty crop growers that was conducted during the spring of 2002. The Risk Management Agency of the United States Department of Agriculture supported the research, and the California Office of the National Agricultural Statistics Service helped conduct the survey. Specialty crops, also referred to as horticultural crops, include tree and vine crops, vegetables, and ornamental crops.

The statistical profile of California’s horticultural farm industries presented here is the most comprehensive ever undertaken for these industries, drawing on survey data collected from approximately one-third of all horticultural crop producers in the state. Specialty crops are diverse. They differ in their product characteristics, production processes, and market environments. Such heterogeneity extends to risk characteristics of the crops and to the ways farmers cope with various risks. As a preliminary step to development of effective risk management tools, it is important to better understand factors that affect these risks. This report is intended to provide such information to help us understand specialty crop industries, the sources of risk, and behavioral risk responses in these industries. The following summary of results is organized by topic.About 86 percent of the farms surveyed produced primarily orchard and vine crops, 5 percent produced vegetable crops, and 9 percent produced ornamental crops. About 25 percent of the farms were located in coastal areas, 13 percent in the Sacramento Valley, and 47 percent in the San Joaquin Valley. The remaining 15 percent were in the northern mountain areas, the Sierra Nevada, the Southern coast, and the deserts. Average farm size was 203 acres, but the median farm comprised only 34 acres. The average number of acres per farm varied substantially among the three crop categories: fruits/nuts, vegetables, and ornamental crops. The average land holding by vegetable growers, 1,106 acres, far exceeded the average of 157 acres for fruits/nuts and 200 acres for ornamental crops. These land figures include land planted to secondary crops . When we examined land planted only in primary crops, our data showed that fruit/nut and vegetable farmers held, on average, about 50 percent of their land in primary crops . However, land for ornamental crops, on average, accounted for only 10 percent of the average 200 acres per farm.

Crop diversification has long been recognized as an important risk management tool. Our data showed that crop diversification was much less common for orchard farms than for vegetable farms. About 70 percent of fruit/nut farmers were single-crop growers as opposed to 26 percent for vegetable farms. The scope of diversification also differed. Fruit/nut farmers predominantly diversified their crops with other varieties of fruits and nuts; only 20 percent of them used crops other than fruits and nuts for diversification. Vegetable farmers, on the other hand, frequently used other crops for diversification; only one-third of the vegetable farms were diversified among only vegetable crops. Our survey also indicated that primary crop acreage increases with crop diversification for both fruit/ nut and vegetable crops. Farms growing five or more vegetables were, on average, four times larger in vegetable acreage than farms growing a single vegetable crop. In California, 6 percent of specialty crop farmers had some organic or transitional-organic land. In terms of crop category, these farms represented 6 percent of orchard farms, 14 percent of vegetable farms, and 4 percent of ornamental crop farms. Our data showed that these farms also engaged in conventional farming and that they devoted, on average, about one-third of their primary crop lands to organic farming. Judging from acreage assigned to primary crops, nursery grow bag the farms were about average in acreage for fruit/nut farms but much smaller than average conventional vegetable farms.Marketing is an important component of risk management. Marketing channels vary by product use . Processing crops are delivered in bulk directly to processing plants, whereas fresh-use crops are sent to operations to be sorted, packaged, cooled , and distributed through marketing channels. California producers were highly specialized in terms of use. Most fruit/nut farms produced mainly for processing use and most vegetable farms produced mainly for fresh use . Only 7 percent of specialty crop farmers supplied both processing and fresh market outlets. In processed-use markets, contracts played a major role with contracts with a predetermined price being the most prevalent form. In fresh-use markets, grower/shippers, which combine the packing/shipping business with field production under one ownership, provide a form of vertically integrated business. Our survey showed that grower/shippers accounted for 13 percent of vegetable farmers and 3 percent of orchard farmers and that they mainly supply mass merchandisers . The other fresh-market growers tended to use diverse marketing channels, including selling directly to consumers, marketing through cooperatives and independent shippers, and selling directly to commercial buyers. For fresh vegetable markets, “directly to consumers” was the most commonly used outlet , not by volume of production but by number of farms using this marketing channel.We investigated year-to-year yield variations using yield information for the preceding five years. Taking the average of the five annual yields as an individual’s normal yield, we calculated the percent deviation from the normal yield and then arrived at sample mean deviations for sample categories. Our data indicated that annual yield deviated, on average, 15 percent for fruits/nuts and 8 percent for vegetables over the previous five years. For price and profit fluctuations, we elicited information on the range of the highest fluctuation experienced over the same five year period . For both price and profit, the median of the accumulated distribution fell in the 25–49 percent range for fruits/nuts and the 10–24 percent range for vegetables, indicating that prices as well as profits tend to fluctuate less for vegetables than for fruits/nuts. In response to a list of options as the main cause for the lowest profit, “poor yield,” “low market price due to high domestic production,” and “low market price due to imports” were the three most often cited causes for all crops except ornamentals. They accounted for 70 percent of the responses for fruit/nut and vegetable farmers. For fruit/nut crops, poor yield was the most cited reason for the lowest profit , but for vegetables, low market price due to high production was cited most , followed by low market price due to imports .

This underscores the relative importance of production risks for orchard crops and of market risks for vegetable crops.Two sources of risk, adverse temperature and output price fluctuation, were listed as most important; input price fluctuation, pests, and disease were considered to be moderately important. Crop insurance was a preferred risk management tool for orchard and vineyard farmers, and crop diversification was preferred by vegetable and ornamental crop growers. Diversified marketing was reported to be the second most preferred tool for all three crop categories. We also surveyed farmers about the availability of risk management tools. As expected, their preferences were closely linked to availability. The most available tools were crop insurance for orchard crops and crop diversification for vegetables and ornamental crops . Orchard and vineyard farmers reported relatively limited availability of other risk management tools.About 53 percent of fruit/nut farmers, 31 percent of vegetable farmers, and 13 percent of ornamental crop farmers said they had purchased crop insurance in the preceding five years and most of those farmers had purchased it for all five years Single-peril insurance is mostly offered by private firms, most commonly for damage from frost, rain, and hail. This insurance was purchased by about 20 percent of fruit/nut farmers and about 10 percent of vegetable farmers. Many farmers suggested that a higher yield guarantee would improve crop insurance. Further, most farmers strongly suggested the need for crop insurance that compensates in value terms, but they expressed no strong preference among compensations based on gross sales, profits, or production costs.Financial variables examined were off-farm incomes, gross sales, debts, and assets. Clearly, the portion of household income risk attributable to variation in farm income decreased as the share of off-farm income rose. For our sample, an average of 63 percent of income came from off-farm sources. A sizable segment of farmers, as many as 25 percent, derived less than 1 percent of their income from farming in the year sampled. This is consistent with the observation that many of the farms were quite small, many farms operated at a loss in any given year, and there was a relatively large number of so-called “hobby” farms in California. Gross agricultural sales averaged about $0.4 million per farm for the entire sample. Vegetable farms averaged $1.1 million in sales, followed by ornamental crop farms with $0.8 million, and orchard farms with $0.3 million. About 6 percent of fruit/nut farms had sales of more than $1 million, compared to 29 percent for vegetable farms and 13 percent for ornamental farms. Agricultural sales were negatively correlated with off farm income share and positively correlated with acreage. Revenue per acre decreased as acreage increased. Given that specialty crops vary widely in unit value and in value per acre, this indicated that farms with fewer acres tended to grow crops with a high value per acre.

When I commented on the apparent lack of urban agriculture activity in Oakland in the mid 1990s compared to what was happening in Berkeley, Daniel Miller, founder of Spiral Gardens, replied, “Oh, there was plenty of urban agriculture taking place in Oakland back then. It was just happening in folks’ yards” . As I explain in Chapter 2 and in my discussion of the Black Panthers in Part 1 above, most of Oakland’s African American population can be traced to a large wave of migration from the rural South during World War Two. Many younger African Americans in the flatlands—second or third generation Oaklanders—talk about how their parents or grandparents grew up on a farm and what they used to grow. Many participants in flatlands urban agriculture programs—City Slicker Farms’ Backyard Gardening Program in West Oakland, for example—are middle-aged African Americans who grew up eating from their parents’ gardens in Oakland, Berkeley, and Richmond. More recent arrivals have carried on such an agrarian tradition. The rolling range and orchards of the Peralta family’s Rancho San Antonio was long ago transformed by several waves of industrial and residential capital. Yet amidst the dense mix of once-stately ramshackle Victorians, craftsman bungalows, and worn out apartment complexes built in the 1960s and 70s, nursery pots tiny patches of Asian bitter eggplants and runner beans and Mexican quelite greens thrive. Fruitvale has long been Oakland’s Latino enclave.

San Antonio is the city’s most ethnically diverse district: 42% Asian and Pacific Islander , alongsidesignificant African American , Latino , and white populations . Many of these residents were settled in the neighborhood in the 1970s and 1980s, fleeing the economic and political repercussions of post-war Southeast Asia. Several refugee relocation organizations such as Lao Family Community Development, the International Rescue Committee, and Refugee Transitions are either located in this part of Oakland or locate families here due to affordable rent, proximity to public transit, and the presence of existing communities . Arrivals of refugees from around the globe—ethnic Nepalis from Bhutan, Burmese Karen and Karenni, Meskhetian Turks from Russia’s Black Sea region, Bosnians, Ethiopians, Eritreans, and Iraqis—have added to San Antonio’s ethnic diversity since the 1990s. Many of these recent immigrants come from agrarian backgrounds and cultivate vegetables in their yards. As I discuss in Chapter 1, immigrants such as these engage in urban agriculture for a number of reasons: to supplement their diets, to sell produce informally to other immigrants, to alleviate boredom, stress, or isolation in a strange new environment. For many it is a way to maintain ties to their homelands and cultural identity through agricultural and culinary traditions . Several coordinated urban agriculture efforts have taken place in this part of Oakland. In 1999 and 2000, garden activist Grey Kolevzon worked with community members and the Friends of Peralta Hacienda Historical Park to start an afterschool educational garden program at the Peralta House in San Antonio, the historic homestead of the Rancho San Antonio. Once the program was up and running, Lao Family Development, one of the resettlement organizations, proposed connecting the schoolchildren with Mien refugees at the Peralta garden, as well.

Lao Family had been having trouble advancing a literacy program for Mien youth. Inspired by a school in nearby Richmond that had created a successful tutoring program that brought Southeast Asian youth together with elders, the organization invited Mien elders to teach the youth about gardening. The project was hugely popular among the youth and their parents and an unexpected outcome was close collaboration between the neighborhood’s African American youth and Mien elders . The educational garden grew into a community garden that remains under the care of a number of Mien, Latino, and African American families . In 2003 the Alameda County Public Health Department, Oakland Unified School District, and EBAYC partnered with a number of other organizations including Cycles of Change, Urban Ecology, Oakland Children’s Hospital, Clinica de la Raza, the City of Oakland Parks and Recreation Department, and several community groups to form San Antonio Neighbors for Active Living. This umbrella organization applied for and acquired a Healthy Eating, Active Communities grant from the California Endowment, a foundation that funds health and wellness projects. While the initiative was broad in scope, one of the program’s goals was to “Establish and expand local and family-operated urban farms to supply organic fresh produce to school-based produce stands and neighborhood stores”. One of the projects funded was the development of the San Antonio Park Community Garden . As with Peralta House, immigrant parents were interested in the afterschool gardening program underway at Roosevelt Middle School in San Antonio. The grant allowed EBAYC/Cycles of Change to expand the program into San Antonio Park, across the street from the school. The grant also helped San Antonio residents establish and run Full Circle Farms in neighboring Alameda and Sunol, a peri-urban community 25 miles from Oakland . This is perhaps because they are growing for household consumption, an act not seen as particularly radical or tied to a particular movement.

Indeed, like the home gardens dotting the yards of Oakland’s industrial garden half a century earlier, the motivation for many is simply to grow food for their families. For many these gardens are also a means of maintaining cultural ties or agricultural and culinary knowledge, rather than an expression of a particular lifestyle politics or a radical rejection of the corporate food regime. Their invisibility, I argue, is also a result of the growing institutionalization of the urban agriculture movement and the development of the “non-profit industrial complex” that has both subsumed and fueled the urban agriculture movement in Oakland. Ironically, while these urban farmers are largely absent within the movement, they serve as material and symbolic inspiration for urban agriculture activists throughout the flatlands, providing concrete examples not only of how and what to grow in the city, but also what the city should look like and how its denizens should feed themselves. By the early 2000s, these various threads had begun to converge. The radical activism of the Black Panther Party and community coalitions of EJ activists laid the foundations of struggle against the devaluation of Oakland’s flatlands neighborhoods and forged the necessary links across race and class to draw attention to their struggles. Urban Habitat’s “flatlands framework” helped to illuminate environmental injustices in the East Bay and aided in this rescaling of the claims of neighborhood activists, expanding their spaces of engagement to include mostly white, mostly Berkeley-centered allies from the environmental, community gardening, and sustainable agriculture movements. The fusion of their concerns resulted in a social, economic, and environmental justice-oriented engagement with gardening that was able to tap into new funding streams for job training and school garden-based nutrition education. Activists sailed freely between projects and organizations, between Berkeley, San Francisco, Oakland, and the Bay Area hinterlands, plastic planters following funding streams and leaving behind new gardens in their wakes. Over the last decade, a new food justice-oriented urban agriculture movement has taken root in Oakland’s devalued flatlands, one that activists have built on a historical foundation of radical activism while drawing on the human and material resources of an increasingly institutionalized network that bridged urban agriculture, nutrition, and economic development and that was legitimate in the eyes of funders. This growing network of radical activists, urban gardeners, and institutions was new; it was more overtly political than the community gardening movement of the past, with more of a multi-racial, cross-class draw. It was even more political than the community food security movement that took hold in mid-1990s, drawing more explicitly on the spatial justice framework to define the inequities of food access in the flatlands and on the historical legacy and symbolism of Oakland’s past and contemporary social justice and EJ activism. Through its increasing connection with institutions, it has also been better positioned to interface with planners and policy makers. The new “food justice” movement has embraced urban agriculture as a key component. Urban agriculture is about more than simply urban gardening. It is a political act, a rejection of the corporate food regime and commitment to overcoming the devaluation of the flatlands. Indeed, even the use of the term “urban agriculture” is an act of scalar politics, whether conscious or unconscious; by calling what they do urban agriculture rather than community gardening, food justice activists in the flatlands are connecting their actions to those of urban residents in the slums of the Global South struggling to mend the metabolic rift inherent to urbanization . Furthermore, the adoption of the term urban agriculture also legitimizes urban food production by tapping into a decade of advocacy for urban agriculture as a sustainable development strategy in the Global South .

By invoking this new “scale frame” , food justice activists have expanded their space of engagement to a global scale, not unlike the BPP succeeded in doing decades earlier . 90 Also like the BPP movement, the city’s food justice activism in has been centered in West Oakland since the dawn of the new millennium, and urban agriculture has, in some ways, provided a new channel for the Panthers ideological legacy. Concerned with the lack of nutritious food in West Oakland, David Roach started up a farmers market at McClymonds High School in West Oakland in 1994. Four years later he started up an organization called Mo’ Better Foods that has worked to cultivate relationships between the few African American farmers still operating in California and West Oakland residents. Roach, an African American and key figure in the history of Oakland’s food justice movement, views agriculture as vital to economic development for black communities. In an address to the Ecological Farming Conference, Roach underscored the centrality of agriculture to a community’s self-sufficiency. African Americans need to actively engage in farming “to take care of ourselves… It’s okay to want to be a farmer. I want independence. I want freedom.” In his address, he was critical of the ways in which social services exacerbate poverty rather than investing in real structural reform: “Every agency has pillaged our community,” creating a system of “handouts that lead either to prison or unemployment” . Urban agriculture, according to Roach, should not be viewed as the solution, but rather should be viewed as only a small part of the solution. The structural issues—the decline of black farmers, the lack of community-owned retail selling healthy food, the lack of economic opportunity—must take precedence . Roach, along with Dana Harvey, a white woman, was heavily involved in organizing one of the first collaborative efforts to think holistically about the food system in the flatlands. In 2001, Roach, Dana Harvey, and the Environmental Justice Initiative, a local EJ program, organized the West Oakland Food Collaborative to come up with a strategic plan to improve food access and food security, while addressing the political and economic conditions of the city’s most devalued area. A nine-month planning process, funded by a grant from UC Davis, brought activists and agencies to the same table. In the end, they identified the following as necessary components of a vibrant West Oakland food system: a farmers’ market, liquor store “conversion”, a cooperative grocery, community green space, and small business development . The Mandela Farmers’ Market, and later the Mandela Cooperative Grocery both arose from this initiative . As Alkon explains, the Collaborative “cast the struggles of African-American farmers and foodinsecure West Oakland residents as manifestations of racism and poverty, which can be addressed through the creation of a local food system” , and ultimately served as a “hub for community organizing” . In 2003 another major food justice organization cropped up. Brahm Ahmadi, Malaika Edwards, and Leander Sellers had been working with City Slicker Farms when they decided to expand the network of urban gardens at other sites throughout West Oakland. Once the organization got off the ground in 2003 they hired neighborhood teens to be peer educators. They eventually set up a “mobile grocery”, a brightly colored panel van filled with fresh vegetables that parked in various locations around the neighborhood.

As István Mészáros explains, “the historically primary relationship between man and nature [is] nature’s relation to itself, on the grounds that man is a specific part of nature.” Since “earth is the first condition of man’s existence, land is, of course, absolutely inalienable from man” , and by extension, inalienable from all sorts of non-quantifiable social significance; precisely why Polanyi considered it inseparable. It follows, then, that the expropriation and commodification of land and nature—a process central to the cleaving of social rift—rends not only a material rift between land and labor, but also an internalized rift in our cognitive and experiential understanding of ourselves as functional organisms existing as a part of a larger ecosystem. This alienation from nature is well documented in developmental psychology, education, and evolutionary biology, as well. The shift from direct to “increasingly abstract and symbolic” contact with the outside environment in the contemporary political economy limits affective, cognitive, and evaluative development in children , leading to a rise in childhood behavioral problems, popularly referred to as “nature deficit disorder” . Several studies have concluded that exposure to vegetation and green space is essential to children’s cognitive development, can reduce attention deficit disorder, and reduce crime and “mental fatigue” or desperation in impoverished urban areas . From the Marxian perspective, black flower buckets the de-alienation of humans both from the fruits of our labor and from the natural or biophysical world depends on our active metabolism of nature through labor.

By physically laboring the soil, sowing seeds, cultivating, harvesting, and preparing food, urban agriculture mends individual rift by reengaging individuals with their own metabolism of the natural environment. Not only do experiences in the garden bring the urban farmer, gardener, or beekeeper into direct contact with the biophysical environment—soil, plants, water, sunshine, rain, worms, insects, birds—as prescribed by the behavioral scientists cited above, but also allows him or her to experience and metabolize the surrounding landscape, transforming it into a product that he or she can consume. The urban farmer’s labor thus sutures individual rift, reintegrating the human with nature as well as de-alienating the laborer from the fruit of his or her labor. In this case, labor’s fruit is more than metaphor, as it may indeed be a fruit, vegetable, honey, milk, eggs, or meat. Several public health and education studies have linked urban agriculture to enhanced natural science and nutritional knowledge, and improved mental and physical health . Recent immigrants to North American cities rely on urban agriculture as a means of alleviating boredom and putting their agrarian skills and knowledge to work. For Hmong women in Sacramento, urban gardening “structured their time, and provided a sense of accomplishment, as they grew their own produce, and supplied their children, grandchildren, and families with food,” countering the culture shock and feelings of dependence and uselessness they felt upon arrival to the US . A study by Airriess & Clawson on urban agriculture practiced by Vietnamese refugees in New Orleans reported similar findings. Such attempts to overcome individual rift by reengaging with the processes of food production and consumption lie at the center of the urban agriculture movement in the Global North. As I argue above, urban agriculture arises as a counter-movement in response to economic crisis and to the commodification of land and labor. Yet viewing urban agriculture in this way alone does not fully grasp urban agriculture’s multiple origins, functions, and forms.

Focusing on individual rift—particularly in the North where a longer history of wage labor has perhaps rendered alienation from manual labor and the biophysical environment more acute— helps to illuminate the important role that urban agriculture serves in late capitalist economies while differentiating its various forms. While guerrilla gardening and food justice initiatives may arise from an explicitly counter-hegemonic challenge to the capitalist food system as described in the previous section, the groundswell of interest in backyard and community gardening appears to be largely linked to efforts to lessen the impact of individual rift and is not necessarily radical. While individual rift is arguably much more widespread in the North than in the cities of the South where linkages to agrarian livelihoods remain intact, within a generation or two, urban dwellers in the South may also experience similar alienation from their food. The words of a young woman from Bamako poignantly illustrate this: “Why should we care about agriculture, about soil erosion? That’s the domain of rural peasants” . While I’m not arguing that everyone can or should grow his or her own food, my intention is to show how the practices associated with urban agriculture—tilling, planting, weeding, watering, harvesting, composting—are a force of de-alienation. Urban agriculture, from this perspective, can help reestablish a conscious metabolic relationship between humans and our biophysical environment by reintegrating intellectual and manual labor. It is also important to emphasize that this dimension of rift is a necessary prerequisite to the ongoing expansion of capitalist modes of production. If, as Marx argued, nature is alienable from humans, we can easily make the link between ecological and human health; damage to the environment is therefore damage to one’s self. Moreover, complacency towards what we would otherwise perceive as self-destructive actions depends on individual rift; to perceive and experience environmental degradation as a solely external process rather than one simultaneously internal and external depends on this alienation.

Recognizing this form of rift and understanding the forces which cleave it is therefore an essential first step to mitigating it. It is precisely in these flat lands neighborhoods that the city’s food deserts can also be found. And it is here that food justice movements have taken root. Yet to better understand Oakland’s food deserts and to recognize the emancipatory potential of urban agriculture and other food justice initiatives that have emerged as a solution, it is helpful first to understand the forces that have hewn the urban landscape into a crude mosaic of parks and pollution, privilege and poverty, Whole Foods and whole food deserts. Few studies move beyond a geospatial or statistical inventory of food deserts to unearth these historical processes. In this chapter I focus on the structural role of capital in order to emphasize the extent to which the history of capital defines the urban environment. Driving down MacArthur or International Boulevards “in the cuts”, the rough and tumble street scapes of the Oakland flat lands, provides a glimpse into how capital’s dynamic cycles—its ebbs and flows—have shaped both the built environment and the social relations woven through it, leaving an almost entirely treeless and worn landscape of used car dealerships, taco trucks, liquor stores, dilapidated storefronts, and the occasional chain linked vacant lot. Understanding the historical and structural roots of this urban landscape is fundamental to understanding the individual and collective agency that adapts to or resists its development. Indeed, the history of the contemporary urban agriculture movement in Oakland really begins here. With this in mind, I tap existing histories of Oakland and urbanization in California, demographic and economic data, and current “grey literature” to broadly trace the historical geography of Oakland’s flatlands during the periods of industrialization and deindustrialization, roughly from the turn of the century to the “neoliberal turn” of the 1980s. I draw on theoretical insights from the growing field of urban political ecology to shed light on the structural processes that have restricted access to healthy food for residents of the flatlands, arguing that a combination of industrial location, residential development, city planning, french flower bucket and racist mortgage lending unevenly developed the city’s landscape and concentrated the impacts of capital devaluation within the flatlands, a process I refer to as “demarcated devaluation” and which ultimately created the city’s food deserts. Nevertheless, at the risk of being seen as an economic determinist, I want to focus on one process that is fundamental to the transformation of the urban landscape and the creation of food deserts: the devaluation of certain types of capital. It under girds the structural processes of uneven development and the social disruption that emerges in response. Nowhere is this process so readily apparent as in post-industrial cities such as Oakland. Cities are ground zero of humans’ transformative power, where the influx of capital is visibly inscribed on the landscape in the form of buildings and infrastructure, as roads, bridges, power lines, rail lines, sewers. During historical moments of capital over-accumulation following economic booms, surplus capital is invested in this kind of fixed or immobile capital, transforming the urban environment. During economic downturns, as capital retreats from urban industrial zones, the post-industrial city nevertheless retains its industrial character, albeit devalued, dilapidated, and scarred by pollution.

The built environment of the past inhibits future investment because it is simply cheaper to go elsewhere. Rents fall, unemployment rises. Both labor and fixed capital are devalued. Harvey writes, “The geographical landscape which fixed and immobile capital comprises is both a crowning glory of past capital development and a prison which inhibits the further progress of accumulation” . These zones left fallow inside the city by capital’s retreat belong to what Richard Walker has called “a lumpengeography of capital,” or “a permanent reserve of stagnant places” awaiting new investment once land and labor values have been sufficiently devalued.44 From this perspective, the contemporary cityscape is a map of previous cycles of capital accumulation and devaluation, a palimpsest of building, decay, and renewal. The walls of this prison of fixed capital are often clearly delineated by planning, policy, property taxes, and political boundaries. These buttresses and ramparts, whether or not they were crafted with intention, effectively demarcate and quarantine devaluation to prevent its impacts from bleeding over, both metaphorically and materially. As environmental justice literature reveals, this process of demarcated devaluation has been highly racialized historically through zoning, redlining, and neighborhood covenants . Human populations viscerally experience these ebbs and flows of capital. As countless cases in the era of deindustrialization illustrate, capital devaluation has historically been the harbinger of social upheaval in the form of migration, poverty, hunger, crime, and declining public health. Given the extent to which the urban landscape is shaped by capital and its crises of accumulation, urban social struggles against the socioeconomic upheaval that follows are interwoven with struggles for a more equitable environment. Perhaps less obvious to many mainstream environmentalists, struggles to protect or clean up the urban environment are equally as entwined within struggles for social justice; as Swyngedouw and Heynen point out, “processes of socio-ecological change are…never socially or ecologically neutral” . Understanding the food justice movement in Oakland and elsewhere therefore depends on understanding the structural forces, generally, and capital devaluation more specifically, that gave rise to the movement in the first place. Applying this analytical framework, I devote the remainder of this chapter to outlining Oakland’s 20th century history of industrialization and deindustrialization, demarcated devaluation, and the consequent creation of the city’s food deserts.In reference to her childhood home of Oakland, Gertrude Stein famously wrote, “there is no there there.” While these words have been used to belittle Oakland for the seventy years that have passed since their publication, they remain poignant when taken in their original context. Stein had returned to the city decades later and was unable to recognize the childhood home of her memories in the vast expanse of new housing sprawling eastwards from downtown . The transformative power that had effaced the “there” of Stein’s turn-of-thecentury childhood home continued to reshape Oakland as industrial and residential capital flowed and ebbed throughout the rest of the twentieth century. Advertising Oakland as a “city of homes,” speculators from the mid-19th century onwards hoped to cash in on its proximity to San Francisco’s bustling commercial center . The promise of the seemingly paradoxical union of Arcadia and Utopia that was the aesthetic hallmark of California development—pastoral landscapes embodied within an ordered, neighborhood logic —fueled a vibrant housing sector in Oakland, drawing the wealthy merchant class to the Oakland hills and foothills. Echoing the language of Mayor Horace Carpentier’s 1852 speech , a booster for housing in Oakland’s lower foothills in 1911 advertised “home sites from which [to] look down on the cities about the bay…far removed from the dirt and turmoil of the work-a-day world” . At the same time, completion of the transcontinental railroad and construction of its terminus in Oakland in 1869 accelerated the expansion of industry from San Francisco to the East Bay; the arrival of iron works, canneries, cotton and lumber mills, breweries, and carriage factories fueled further industrial agglomeration around the rail terminals in West Oakland and the estuary waterfront at the southern edge of downtown .

Optimum values for Fv/Fm are 0.80–0.83 in C3 plants . Mortality of an individual was assessed by using the stress index, inspecting the texture of the leaves, and evaluating gas exchange and dark-adapted fluorescence values. An individual was determined dead and harvested immediately if it had a stress index score of five or higher, leaves were crispy instead of flexible, and if at least two leaves measured Anet and Fv/Fm values of less than 0.5 µmol CO2×m-2 ×s-1 and less than 0.300, respectively. Stems of harvested plants were checked for lesions by scraping the bark away from the POI and looking for darkened, necrotic tissue extending upward from the POI. Lesion length was measured in centimeters from the POI to the farthest advancing margin of the lesion. Soil moisture, plant structure, physiological data, and disease severity were statistically compared using ANOVA in JMP, version 14 Pro , and post hoc analyses of means were performed using Wilcoxon signed rank test. Two-way factorial ANOVAs were conducted on the influence of watering regime , inoculation treatment , and interaction effects between watering regime and inoculation treatment on plant Anet, Fv/Fm, and disease severity. Correlations between disease severity and physiological stress responses were also examined in JMP using a linear regression analysis to determine maximum fit. Survivorship of each treatment group was estimated using the Kaplan–Meier survival analysis with the survival package in R v. 3.5.1 .

A Cox proportional-hazards model was followed by a Peto and Peto post hoc test to test for statistical significance of Kaplan–Meier survivorship. Due to the small sample size of individuals available for the experiment, procona buckets all reported results for survival were based on a 90% confidence level, and P-values above 0.05 but below 0.1 were considered significant trends. All other tests were conducted using a 95% confidence level for significance.Both chlorophyll fluorescence and net photosynthesis declined as hosts were exposed to drought and fungal infection. Each of these factors caused measurable physiological stress in A. glauca individually; however, in combination, stress symptoms showed up earlier and more strongly . Additionally, an important result was the relationship between visible stress symptom severity and physiological function. Both Anet and Fv/Fm were found to be highly correlated with visible signs of stress that ultimately led to plant mortality. This is consistent with previous studies that have found that Fv/Fm correlates strongly with eventual mortality, and therefore, can be an indicator of drought-related mortality risk in natural systems . Furthermore, Anet was shown to decline even with very low levels of visible stress, suggesting it may be valuable as an early detector of plant stress even before major visible symptoms appear. While Anet and Fv/Fm can be useful tools for measuring physiological stress, they are expensive and difficult to measure on the ground at large scales. Therefore, using visible stress severity indices may be a promising and cost-effective method with which to quickly carry out large surveys aimed at predicting drought- and fungus-related mortality in the field. High mortality was observed in all inoculated plants regardless of drought treatment, indicating that N. australe may act as an obligate pathogen on A. glauca, at least in young, small individuals as were used in this study.

However, mortality occurred much faster in the D+ group. Additionally, some individuals in the D- and W+ group at Week 10 survived well beyond the termination of experiment , suggesting the ability of A. glauca to allocate sufficient resources for defense against drought stress, and in some cases, infection by N. australe, but a greater vulnerability in the simultaneous presence of both factors. Therefore, it appears that a synergistic interaction does exist whereby exposure to both drought and infection by N. australe yields more accelerated decline than either factor alone. It is likely that A. glauca susceptibility, or “predisposition” to disease , is due to the interactive roles of water and carbon availability in plant defenses against drought stress and biotic invaders, as modeled by McDowell et al. and Oliva et al. . Their framework describes a system in which plant hosts are able to allocate resources to either survive extreme environmental stress or defend against biotic invasion, but may succumb via depleted carbon resources when exposed to multiple stressors. For example, hosts like A. glauca can persist through drought with high resistance to cavitation . They can also divert carbon resources to block the spread of pathogens . However, the combination of global-change-type drought and infection by pathogens like N. australe may leave these hosts vulnerable when they no longer possess the resources needed to simultaneously resist cavitation and invasion by the pathogen.

Furthermore, extreme drought conditions can enhance optimal conditions for the growth of pathogens like Botryosphaeriaceae fungi that thrive in more negative water potentials than the host can withstand . These factors combined can push the host beyond a threshold, increasing branch dieback and ultimately increasing the likelihood of whole plant mortality. Understanding the role of pathogens and drought stress in native vegetation canopy loss has long been of great interest to ecologists, though research involving such systems has yielded varying results regarding these interactions. For example, a meta-analysis by Jactel et al. found that in studies on the effects of pathogens and insects on forest plant hosts during drought, damage to hosts varied greatly based on the feeding habits and substrate of the pathogen and severity of the water stress. In the case of secondary agents , more damage occurred on hosts experiencing water stress compared to non-stressed controls, and damage severity increased with increasing water stress. These findings are consistent with the results of the present study and support the hypothesis that drought stress predisposes hosts to pathogen impacts. Other studies have found similar results regarding secondary pathogens in drought-tolerant plant systems, including red pine forests , eucalyptus forests , and chaparral shrublands . By contrast, Davis et al. concluded that drought-induced cavitation alone, not infection by Bot. pathogens, caused canopy dieback of southern California Ceanothus sp. during drought, suggesting that secondary agents do not always benefit from drought-related predisposition. Clearly, while secondary pathogens are known to become pathogenic in hosts experiencing environmental stress , the mechanisms driving this relationship in different plant hosts are not fully understood. Although field studies have been conducted on the presence of fungal pathogens on shrubland species during drought , controlled experiments manipulating both drought and fungal treatments in naturally occurring species are rare and typically involve tree systems rather than wildland shrub species . To the authors’ knowledge, this is the first experiment to investigate the influences of drought and infection by N. australe on A. glauca by manipulating both factors.The results of this experiment, along with the identification of N. australe and other Bot. species in the region , suggest that the severe canopy dieback of A. glauca observed in Santa Barbara County between 2012 and 2016 is likely the result of global-change-type drought combined with the presence of opportunistic fungal pathogens like N. australe. While there is evidence to suggest that acute drought alone may cause some mortality in A. glauca , procona florida container the presence of N. australe and other pathogens likely exacerbates stress and accelerates mortality in these hosts. Furthermore, N. australe has long been reported in avocado orchards in Santa Barbara County ; however, there are no known reports or indications of major disease and dieback of A. glauca in surrounding chaparral shrubland system until recently, during the especially dry winters of 2013 and 2014 .

Thus, we suspect that while N. australe has likely been present on A. glauca hosts , the drought of 2011–2018 was the most severe in the region in the past 1200 years and may have been significant enough to push adult A. glauca past a tipping point of defensibility against N. australe. It should be noted that results of experiments on young plants, which may be highly susceptible to drought and drought-related mortality due to limited carbon reserves, may not scale directly to large, mature individuals in the field . This study showed high mortality in 2-year-old A. glauca exposed to a fungal pathogen with and without drought, in contrast with field observations of diseased, large adults exhibit severe canopy dieback and are ridden with fungal cankers, yet still survive . Previous studies have yielded similar results: for instance, photosynthesis was shown to be greatly reduced in oak seedlings compared to adults in drought years compared to wet years , and He et al. reported that responses of red maple and paper birch saplings to a 1995 drought were significantly different than those of mature adults. Similarly, since hosts are often able to allocate carbon reserves to compartmentalize canker-causing agents like N. australe within carbon-rich barriers , larger individuals with more biomass and greater carbon stores are able to utilize and direct more resources to defense than younger, smaller individuals. Thus, mature plants can better persist through biotic attack during environmental stress than their younger counterparts and experience various levels of canopy dieback rather than full mortality. Arctostaphylos glauca are obligate seeders, meaning they are killed by fire and must maintain populations by individuals recruiting from seed rather than resprouting from their base. Therefore, young, small individuals may be of greatest concern for future populations of this species. Because current research is predicting more frequent and extreme drought events , more exotic pathogens , and more frequent fire in these southern California shrublands , populations of A. glauca could decline because small individuals may be highly susceptible to disease and mortality. A valuable next step for understanding these risks and predicting future shifts in vulnerable chaparral communities would be to monitor young recruiting populations of A. glauca for N. australe for signs of stress, infection, and mortality in the wild.In the face of rapid climate change, it is increasingly important to understand the abiotic and biotic mechanisms driving ecological landscape change. Large plant dieback events can produce major ecological consequences, including changes in vegetation cover , increased fire risk , and changes in hydrology , all of which affect ecosystem structure and functioning . Furthermore, the loss of even a few species can trigger effects on the local food web structure , and increase risk of invasion . The results of this study suggest that small individuals of A. glauca, one of the most common and widespread species the southern California chaparral community, are at high risk of disease and dieback due to opportunistic pathogens and extreme drought. The potential for dieback of Arctostaphylos spp., which provide food for animals such as mice, rabbits, and coyotes and are an important component of post-fire woody regeneration in chaparral, raises concerns regarding changes to ecosystem structure and functioning in the coming decades. Many ecosystems today are facing unprecedented drought ; yet, the interactions of drought and pathogens in wild land settings are difficult to study because the multitude of confounding variables and the challenges of manipulating both the pathogens themselves and climate. Thus, greenhouse studies such as this one are increasingly essential to understand the influences of drought and pathogens as they relate to dieback events, as well as to understand the relationship between stress and shrub/tree ontogeny . Critical questions remain regarding the relative tipping points for large-scale dieback among historically drought-tolerant species such as A. glauca that today are facing the combination of extreme drought and novel pathogens. These pathogens may not express themselves until there is drought, highlighting the need for broader field surveys and long-term monitoring of wild land ecosystems. An important step to understanding the role of disease in contributing to vegetation change is also to isolate pathogens and test their pathogenicity under varying controlled conditions. This study provides one such step for what appears to now be a widespread, opportunistic introduced pathogen in an important native California chaparral shrub. Extreme drought events from climate change have produced immediate and dramatic effects in recent years, with costs often exceeding $1 billion due to their widespread economic and ecological impacts . Among the ecological consequences is widespread tree mortality, , event within plant systems that have historically been considered drought-tolerant .