A comparative assessment of greenhouse gas emissions in California ...

Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector

A comparative assessment of greenhouse gas emissions in California almond, pistachio, and walnut production Elias Marvinney1,*, Alissa Kendall2, Sonja Brodt3 1

Department of Plant Science, University of California, Davis Department of Civil and Environmental Engineering, University of California, Davis 3 Sustainable Agriculture Research and Education Program, University of California, Davis  Corresponding author. E-mail: [email protected] 2

ABSTRACT A process-based life cycle assessment (LCA) model was constructed for almond, pistachio, and walnut production in California. Agrochemical inputs, mechanized operations, soil processes, geospatial variation, and biomass accumulation were explicitly modeled based on technical reports, economic cost-and-return studies, field data collection, and grower interviews. Mean annual greenhouse gas (GHG) footprints for a typical hectare of orchard, from nursery to hulling/shelling facility gate, were calculated at 4260 kg CO2e ha-1 yr-1 for almond, 3480 kg CO2e ha-1 yr-1 for pistachio, and 4050 CO2e ha-1 yr-1 kg for walnut. These results can be expressed by orchard product (nut kernel) as 1.76 CO2e kg-1 for almond, 0.95 CO2e kg-1 for walnut, and 3.83 CO2e kg-1 for pistachio. Variations in biomass accumulation, yield and orchard lifespan between these crops result in different total life cycle emissions and potential management options for net GHG reduction and credit opportunities under California GHG cap-and-trade legislation. Keywords: perennial cropping systems, orchard, greenhouse gas footprint, almond, walnut, pistachio

1. Introduction Though LCA has been applied to a wide variety of food production systems, orchards have been examined relatively infrequently, with studies focusing on apple (Milà i Canals et al. 2006; Mouron et al. 2006; Page et al. 2011; Hester & Cacho 2003; Alaphilippe et al. 2012), kiwi (Xiloyannis et al. 2011), and citrus (Coltro et al. 2009; Mordini et al. 2009; Beccali et al. 2009; Beccali et al. 2010). Walnut production has also been examined although primarily in the context of timber production (Cambria & Pierangeli 2011). Many of these studies examine a single year for a production system, and thus do not consider the entire orchard life cycle, which includes orchard establishment, tree growth, and eventual removal (Bessou et al. 2012). Also, these studies generally do not consistently address the flow of carbon and nitrogen through the orchard and the woody biomass generated from orchard systems. This study characterizes the greenhouse gas impacts of typical almond, walnut, and pistachio orchard production systems in the U.S. state of California using a comprehensive process-based life cycle assessment model that specifically accounts for carbon and nitrogen flow in biomass accumulation and fertilizer application. These highly industrialized agro-ecosystems are of great economic and environmental importance, occupying more than 500,000 ha of California agricultural land and yielding more than 83% of world almond production, 46% of walnut production, and 37% of pistachio production (USDA Office of Global Analysis 2013). Commercial orchards in California’s Central Valley demand significant agrochemical, water, and fuel inputs throughout their productive lifespans (Beede et al. 2008; Connell et al. 2012; Grant et al. 2007; Micke & Kester 1997). Irrigation accesses groundwater via on-site pumps and surface water via the California Aqueduct system and other surface water transport infrastructure, entailing significant energy inputs for onsite and upstream pumping. Due to its relatively high input intensity, the California nut industry is responsible for significant emissions of greenhouse gases (GHGs) and other atmospheric pollutants. However, perennial cropping systems such as almond, walnut and pistachio orchards have the potential to sequester carbon in soils and biomass as a consequence of their long life cycles and high biomass production (Kroodsma & Field 2006). In California, much orchard waste biomass is used to produce electricity at regional electricity generation plants, widely distributed in California (Wallace & Leland 2007). The potential for sequestration versus emissions offset through use of waste biomass as an energy feedstock is dependent on management characteristics, orchard lifespan, and other factors. We examined the effects of various biomass fates on net orchard GHG and energy consumption footprints, accounting for potential GHG credits from biomassbased energy production and temporary storage in standing biomass under both a business-as-usual scenario based

761


on estimates of current practices, and a maximized energy production scenario assuming that all biomass coproducts are directed to energy generation.

2. Methods 2.1. Model Development This orchard LCA model was developed originally for analysis of almond production, and subsequently adapted for analysis of walnut and pistachio production. The general model structure remained the same, with multiple years of the orchard life cycle treated separately in order to account for changing input requirements and yields as trees mature, and model subunits for calculation of irrigation energy requirement, soil nitrous oxide emissions, and fuel combustion emissions were identical. The major differences between the three systems are in agrochemical and water input requirements, fuel use in field operations, typical yield per hectare, planting density and biomass accumulation, orchard lifespan and length of time before full bearing, and geospatial distribution and spatial relationships with irrigation infrastructure. Where data were not available, particularly in the case of pistachio and walnut hulling and shelling operations, emissions from pistachio and walnut orchard floor soils, and pistachio nursery sapling production, data were substituted from the almond model (Kendall et al. 2012). Although data on the major system drivers of lifespan, nutrient management, irrigation, and yield are complete for almond, walnut, and pistachio, data collection for some aspects of walnut and pistachio production remains ongoing and will be included in further model iterations and published as stand-alone LCAs of walnut and pistachio production. The results presented are calculated from generalized, statewide data; however, the model framework is also usable for case studies of individual orchard operations. 2.2. Data Collection and Sources To date, the most complete data were available for almond production. Data on input requirements, field operations, planting density, orchard productive lifespan, and irrigation systems were obtained from University of California Davis (UCD) Cost and Return studies. These studies document annual crop production costs for various California crops, by inventorying typical inputs and cultural practices on a regional basis up to the farm gate (M. A. Freeman et al. 2003; M. W. Freeman et al. 2003; Duncan et al. 2006; Connell et al. 2006; Freeman et al. 2008; Duncan, Verdegaal, Holtz, Doll, K. A. Klonsky, et al. 2011; Duncan, Verdegaal, Holtz, Doll, K. M. Klonsky, et al. 2011; Connell et al. 2012; Beede et al. 2008; Grant et al. 2007). The most recent available data was used, ranging from 2003 – 2012 for almond, 2007 for walnut, and 2008 for pistachio. These Cost and Return studies are developed based on data collected from growers, orchard managers, and UC Cooperative Extension farm advisors through surveys, interviews, and focus groups. They provide a picture of the typical nutrient, pesticide, fuel, water use, equipment use patterns (including equipment type and hours of operation), and annual yields for an orchard under a particular irrigation system type in a particular growing region (Sacramento Valley, San Joaquin Valley North, and San Joaquin Valley South). In this LCA, the most conservative available regional data from the studies is used. The term “conservative” here refers to the use of the highest typical input values, which reduces the risk of underestimating inputs and associated GHG emissions. Because growing region and irrigation type can affect key factors such as yield, results are calculated as a weighted average based on the number of hectares of orchard per region, and the type of irrigation system used; flood, micro-sprinkler, sprinkler or drip. Regional distribution information on almond irrigation methods and the proportion of groundwater versus surface water used by growers was obtained from survey data commissioned by the Almond Board of California to develop a sustainability program for the state’s almond growers. For walnut and pistachio, these data were obtained through interviews with UC Cooperative extension crop specialists and farm advisors. One shortcoming of using these studies to inventory inputs and operations is that custom operations, those operations conducted by contractors rather than the orchard owners and managers, are tracked only as a cost in these studies, omitting information such as the hours of equipment operation and chemical or fuel inputs associated with these operations. To fill these and other data gaps in the LCA model, additional data were obtained through surveys of businesses and individuals involved in nut production. Surveys were administered to nursery operators, 762


growers and their orchard managers, custom harvest operators, and orchard clearing operators. These surveys were conducted by both on-line survey and in-person interviews. In-person interviews were conducted to collect data for specific aspects of an operation, particularly equipment use and time needed for various tasks. No primary survey data for individual respondents are reported in this article to protect the anonymity of cooperating individuals and businesses, but wherever possible aggregated or composite results from surveys are provided. Data for hulling and shelling were collected for almond through surveys and interviews of facility operators, as reported in (Kendall et al. 2012). In absence of similar data for walnut and pistachio, almond values were used. Further data collection is ongoing, but given the relatively small contribution of post-harvest operations to the overall GHG footprint of nut production (Figure 5), significant changes to overall net GHG footprints are not expected from the use of walnut and pistachio specific hulling and shelling data. 2.3. Goal and Scope Definition The goal of this project is to conduct process-based LCAs for typical commercial California almond, walnut, and pistachio production to estimate the GHG emissions associated with production activities. Operations and inputs that contribute the most to total emissions and energy (i.e., ‘hotspots’) over the orchard life cycle are also identified to assist growers and policy-makers in targeting the highest-emitting or highest energy-using processes for reduction. The processes and operations included within the LCA system boundary are illustrated in Figure 1 below. The units of analysis are one hectare of orchard assessed over a time horizon equal to the productive lifespan of the orchard plus one year for orchard clearing and fallow: 26 years for almond, 36 years for walnut, and 61 years for pistachio; and one kilogram of nut-meat or kernel (obtained by dividing through by mean annual yield on a kg ha-1 basis) at the hulling and shelling facility gate. Both GHG emissions and yield vary as the orchard matures, so annual yields were averaged over the orchard lifespan including non-productive and fallow years in order to calculate a generalized value for GHG emission expressed on a per kilogram yield basis. This functional unit can be simply converted to nutritional units such as calories of food energy.

763


Figure 1. Orchard LCA system boundary. Transportation emissions, though accounted for at each stage, are excluded for clarity.

764


2.4. Model Assumptions Model assumptions follow those reported previously for almond production (Kendall et al. 2012), and include the following:



  

One percent of trees in each cropping system die and are replaced each year. The land occupied by the modeled orchard is assumed to be continuously planted as orchard, resulting in no net change in soil carbon over an orchard’s life cycle. Though soil carbon changes over an orchard life cycle it is assumed that the soil carbon level at the time of orchard removal is identical to the soil carbon level following orchard establishment, due to loss of soil carbon during land clearing, tillage, and planting. Additionally, since potential carbon storage in soil is highly dependent on site-specific soil characteristics and orchard floor management (Six et al. 2004), accurate assessment of potential soil carbon sequestration in orchards on a statewide basis will require further field data collection and will be addressed in future publications. Different irrigation systems are modeled independently because they result in differences in both water input (including pumping and pressurization requirements) and direct and indirect nitrous oxide (N2O) emissions from the field (estimated using IPCC Tier 2 methods). In terms of N2O emission factors, the different crops are assumed identical and only differences between irrigation systems are accounted for. Agricultural equipment production is unlikely to have a major impact on the results of this analysis and is excluded - an exclusion common in other LCA studies (British Standards Institution (BSI) 2011). For purposes of comparison, each of the three orchard types is examined on a time horizon of 61 years: 1 pistachio life cycle, 1.71 walnut life cycles, and 2.40 almond life cycles. Inputs, especially nitrogen fertilizer and irrigation water (Figure 2), vary according to the nutritional needs of the different crops and the regional climate as well as over time as the orchard matures. 250.00

kg N ha-1

200.00

12,000.00

Almond Walnut Pistachio

10,000.00

m3 H2O ha-1

 

150.00 100.00 50.00

8,000.00


6,000.00 4,000.00 2,000.00 0.00

0.00 1

2

3

4

5

6

1

7+

2

3

4

5

6

7+

Year

Year Figure 2. Variation in applied nitrogen and irrigation water by crop and year.



Irrigation energy use is regionally dependent due to the spatial relationship with surface water delivery infrastructure (e.g., the number of California aqueduct pumping stations upstream of a given water diversion) and average groundwater depth, and thus the region of the Central Valley in which an orchard is located determines the energy requirement and the resulting GHG emissions embedded per unit applied water. A GIS-based model was used to generate a weighted mean irrigation energy value based on prevalent irrigation system types and spatial distribution of almond, walnut, and pistachio orchards. A detailed explanation of this model as applied to almond is available in (Kendall et al. 2012). Pistachio orchards are mostly concentrated in the southern Central Valley where groundwater is deeper and surface water delivery more energy intensive (Klein & Krebs 2005; GEI Consultants & California Institute for Energy and Environment 2010), while walnut orchards tend to be located in the northern Central Valley where surface water is gravity-fed and groundwater is closer to the surface. This results in higher typical irrigation energy use for pistachio and lower for walnut as compared to almond (Table 1).

765


Table 1. Almond, walnut, and pistachio irrigation characteristics. Crop

Irrigation Energy

Main Irrigation Type


0.59 MJ m-3 0.40 MJ m-3 0.83 MJ m-3

Microsprinkler Solid-set Sprinkler Drip

Mean Annual Applied H2O 10307 MJ ha-1 4112 MJ ha-1 4686 MJ ha-1

2.5. Co-product treatment As above, model treatment of biomass co-products including hulls, shells, prunings, and removed trees follows that reported in (Kendall et al. 2012). Some of the major differences between co-product treatment in almond, walnut, and pistachio are as follows: 

Biomass accumulation in almond was modeled according to a logistic curve, fit to measurements of biomass cleared per hectare obtained through collaboration with a Central Valley agricultural services firm. This method results in accurate calculation of total biomass per hectare at the end of the orchard productive lifespan (here 25, 35, and 60 years for almond, walnut, and pistachio respectively), but total biomass at any given year between establishment and clearing remains uncertain. Destructive sampling of individual trees of known age was used in , although actual biomass at end of life could only be estimated based on the logistic growth model (Agueron & Roberts 2013). In walnut, both destructive sampling of trees of known ages and measurements of orchard clearing biomass were used, giving accurate estimates of orchard biomass at all stages of growth. 90000 Almond Walnut Pistachio

80000 70000

kg CO2e ha-1

60000 50000 40000 30000 20000 10000 0 0

10

20

Year

30

40

50

Figure 3. Biomass accumulation as CO2e ha-1 in almond, walnut, and pistachio orchards over a 60 year time horizon.

 

Pruning removal was calculated as a function of total tree biomass per hectare and pruning removal estimates (kg ha-1 yr-1) from mature orchards. This base rate varied from 1060 kg ha-1 in almond to 1460 kg ha-1 in walnut and pistachio (Williams et al. 2008). Ratios of hull and shell to kernel (Table 2) were obtained directly from hulling/shelling facility records for almond, and from literature for walnut and pistachio (Monselise 1986).

766

60


Table 2. Mean annual yield and hull and shell to kernel ratios for almond, walnut, and pistachio. Crop Almond Walnut Pistachio



Shell: kernel mass ratio 0.45 0.77 1.01

Hull: kernel mass ratio 1.56 1.77 2.63

Mean Annual (kernel) 1359 kg ha-1 2631 kg ha-1 1375 kg ha-1

Yield

Mean Annual Yield (total) 4091 kg ha-1 9314 kg ha-1 6380 kg ha-1

Typically, almond hulls are used as dairy cattle feed while pistachio and walnut hulls are mulched. Specific information on shell fate was not available, so shells were assumed to be mulched for all three crops.

As reported in (Kendall et al. 2012), the rate of cleared biomass directed to energy production was reported as 95% for walnut and almond. In absence of specific data, the same rate was assumed for pistachio. The energy content of wood was obtained from (Wallace & Leland 2007), and a reasonably low estimate for power plant conversion efficiency of 0.25 was used to determine electricity generation offsets (Bain 1993). The equivalent emissions from a typical California grid electricity generation mix were considered to be displaced by the electricity produced from orchard biomass. Each kilogram of biomass generates approximately 2.57 MJ of electricity after being dried in-field and at the power plant to approximately 30% moisture. A conservative value of approximately 25% energy conversion efficiency was assumed for California biomass power plants. When almond hulls are fed to cattle they are assumed to displace roughage, assumed to be silage corn, on a one-to-one mass basis. Displacement of electricity and silage corn production by use of orchard biomass co-products results in avoided GHG emissions, and is used to calculate GHG credits through system expansion to include energy generation and cattle feed production (Marland & Schlamadinger 1995). LCI data were obtained from EcoInvent and PE databases, accessed via GaBi software packages (Centre 2008; PE International 2009). 2.6. Temporary carbon storage Temporary carbon in tree biomass is a function of marginal biomass accumulation on an annual basis as well as total storage time (orchard lifespan). Temporary carbon storage is a special case of emissions timing, where a removal of CO2 from the atmosphere followed by an eventual emission occurs. Thus, to account for temporary carbon storage we use an alternative characterization method for GHG emissions, the Time Adjusted Warming Potential (TAWP) (Kendall 2012). The TAWP uses the relative cumulative radiative forcing (CRF) between an emission or removal of a GHG at a particular point in time (within the analytical time horizon of 100 years) and an emission of CO2 today, resulting in units of CO2 equivalents (CO2e) today. The total kg ha-1 in CO2e added per year in almond, walnut, and pistachio tree biomass was estimated using the logistic biomass model described above and in (Kendall et al. 2012), along with the total biogenic emissions from lost biomass at orchard clearing in order to calculate the TAWP of CO2e drawn out of the atmosphere in tree growth. Storage in prunings, hulls, and shells is not considered in this calculation, as they are assumed to be mulched or otherwise disposed of in the same year that they are produced, resulting in a negligible contribution to carbon storage. 2.7. Scenarios Two scenarios were examined: a typical or “business-as-usual” (BaU) scenario in which the best estimates of current co-product management practices and biomass fates was analyzed; and a maximum energy production scenario in which all available orchard biomass waste was utilized for energy production, including prunings, dead trees, shells, hulls, and cleared biomass at the end of the productive lifespan. Orchard clearing biomass was assumed to be directed to solid fuel power plants throughout the Central Valley as is the current practice, and prunings, shells, hulls, and individual removed trees were assumed to be combusted in modular biomass gasificationpyrolysis systems such as the Biomax system produced by Community Power Corporation (Overend 2004). Detailed discussion of the assumptions entailed in these two scenarios applied to almond production is offered in (Kendall et al. 2012), and the same assumptions applied for walnut and pistachio analysis in this study.

767


3. Results Analyzed over a 61 year time horizon for a business-as-usual scenario, we find that the mean annual net GHG emissions of almond, walnut, and pistachio production are 1771, 2247, and 2986 kg CO2e ha-1 respectively. These results include co-product credits of -1165, -159.8, and -137.9 kg CO2e ha-1 and temporary storage credits of 187.4, -981.3, and -356.4 kg CO2e ha-1 for almond, walnut, and pistachio respectively (Figure 5). Expressed per kilogram yield almond, walnut, and pistachio are responsible for 1.88, 0.89, and 2.17 kg CO2e kg-1 kernel respectively (Figure 6). 4000.0

Emissions

3.00

3480

3388 3124

2.50

3000.0

Temporary Storage Credit Net Emission

2000.0

2247 1771

1000.0 0.0

-356.4 -187.4

-981.3

-137.9

2.00

kg CO2e kg kernel -1

Co-product Credit

kg CO2e ha-1 yr-1

2986

1.50

2.17 1.88 1.29

1.00 0.89

0.50 0.00

-1000.0 -1165

2.53 2.30

-0.50

-159.8

-2000.0

-0.14

-0.37

-0.26

-0.28

-0.03

-0.10

Almond

Walnut

Pistachio

-1.00 Almond

Walnut

Pistachio

Figure 4. Mean annual GHG emissions and credits for nut orchards per hectare and per kilogram kernel under “business-as-usual” scenario. The distribution of emissions among various management categories is roughly similar between almond, walnut, and pistachio, and is dominated by nutrient management at 38-43% total GHG emissions and irrigation at 1634% total GHG emissions. Almond

Other Hulling/ Shelling

Pest Mgmt

Walnut

Hulling/ Shelling

Other Pest Mgmt

Pollination

Nutrient Mgmt

Harvest

Irrigation

Irrigation

Nutrient Mgmt

Other Pest Mgmt

Land Prep

Nutrient Mgmt

Nursery

Nursery

Nursery Biomass Mgmt

Hulling/ Shelling

Harvest

Harvest

Irrigation

Pistachio

Biomass Mgmt

Land Prep

Biomass Mgmt

Land Prep

Figure 5. Breakdown of orchard emissions by management category for almond, walnut and pistachio. The hypothetical maximum energy production scenario resulted in a substantial increase in potential co-product credits and a corresponding decrease in net emissions. Under this scenario net GHG emissions were calculated as -195.2, -981.3, and -84.67 kg CO2e ha-1 and -0.14, -0.16, and -0.06 kg CO2e kg-1 kernel for almond, walnut, and pistachio respectively (Figure 6).

768

Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector 3.00

4000.0

Emissions

3000.0

3124

3388

3480 2.00

2.53

2.30

1000.0

kg CO2e ha-1 yr-1

Co-Product Credit

0.0

-1000.0

Temporary Storage Credit

-981.3

-195.2

-356.4 -84.67

-417.1

-2000.0 -3000.0

Net Emissions

-187.4

-3131

-2824

-3208

kg CO2e kg kernel -1

2000.0

0.00

-0.14

-0.16

-0.06

-0.14

-0.37

-0.26

-1.00 -2.00

-4000.0 -5000.0

1.29

1.00

-1.07 -2.30

-2.33

-3.00 Almond

Walnut

Pistachio

Almond

Walnut

Pistachio

Figure 6. Mean annual GHG emissions and credits for nut orchards per hectare and per kilogram kernel under “maximum energy” scenario.

4. Discussion The mean annual GHG burden, normalized to a 61 year time horizon, is similar among almond, walnut, and pistachio (Figure 4). This is due to the similarities in orchard management practices and to some extent, balances among inputs (Figure 5). For example, in wetter regions more frequent weed control and fungicide application is required, but less water is needed, whereas the opposite is true in dryer regions (Micke & Kester 1997). Somewhat greater differences in GHG footprint are observed when considering emissions per kilogram kernel (Figure 4) and when examining potential co-product and carbon storage credits. The former is due to variations in total yield and yield component ratios between these three crops (Table 2) while the latter is due to differences in co-product utilization (i.e., use of almond hulls as dairy cattle feed) and biomass accumulation characteristics (Figure 3). The scenario analysis highlights the variations between crops in potential to increase GHG credits through management practice – in particular, the expanded use of hull, shell, and waste biomass for energy production can generate significant GHG offsets (Figure 6).

5. Conclusion This analysis examined typical almond, walnut and pistachio production in California using weighted-average data and consensus values for production inputs. As with all agricultural products, these nuts are subject to the inherent variability of region and climate which affects yields, biogeochemical emissions from orchard soils, and cultural practices of growers. This analysis highlights the critical importance of understanding the fate of co-products from orchard production including their utilization for energy production in order to determine true net GHG footprints of production, as well as the importance of maintaining high yields for increased GHG emissions “efficiency” of production (i.e., kg CO2e kg-1 economic product). The examination of a maximum energy scenario revealed the extremely high potential for California nut orchard systems to act as a net reducer of atmospheric GHG concentrations with the adoption of increased biomass co-product utilization practices and technologies. Indeed, due to lack of data, this analysis does not even consider the potential for carbon sequestration in orchard floor soils, which has been estimated as potentially highly significant (Kroodsma & Field 2006), nor does it consider the potential for increased management for biomass production (e.g., increased planting density coupled with periodic thinning, increased pruning frequency, cover cropping and no-till management, etc). Similarly, no scenarios accounting for potential GHG emission reduction through changes in inputs, management, or efficiency at the orchard field and production levels were examined. These represent additional potential sources for greenhouse gas reduction credits that will be explored in future analyses. The results of this analysis suggest that combining the potential biomass management practices considered here with reductions in input intensity and alternative, low-GHG and energy intensive management practices could

769


potentially allow California nut production to act as a significant GHG offset for the state. In order to promote and incentivize these practices, California’s current GHG cap-and-trade legislation (Pavley & Nunez 2006) must properly credit orchard growers with the current beneficial results of perennial crop production, account for both co-product utilization and temporary carbon storage in standing biomass in calculation of net orchard emissions, and actively promote management practices that maximize the GHG benefits of these factors. Further research is needed to refine the walnut and pistachio LCA models and include more regionally specific data, as well as to elucidate the specifics of economic incentives that would be required to achieve optimum adoption of the GHG reducing management practices highlighted in this study.

6. References Agueron, E. & Roberts, B., 2013. Developing allometric equations for estimating biomass of orchard-grown Pistachia vera (L) in California. In Proceedings of the VI International Symposium on Almonds and Pistachios. Alaphilippe, A. et al., 2012. Life cycle analysis reveals higher agroecological benefits of organic and low-input apple production. Agronomy for Sustainable Development, 33(3), pp.581–592. Available at: http://link.springer.com/10.1007/s13593-012-0124-7 [Accessed July 11, 2014]. Bain, R.L., 1993. Electricity from biomass in the United States: Status and future direction. Bioresource Technology, 46, pp.86–93. Beccali, M. et al., 2010. Life cycle assessment of Italian citrus-based products. Sensitivity analysis and improvement scenarios. Journal of environmental management, 91(7), pp.1415–28. Available at: http://www.ncbi.nlm.nih.gov/pubmed/20227818 [Accessed July 11, 2014]. Beccali, M. et al., 2009. Resource consumption and environmental impacts of the agrofood sector: life cycle assessment of italian citrus-based products. Environmental management, 43(4), pp.707–24. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19184189 [Accessed July 11, 2014]. Beede, R.H. et al., 2008. Sample costs to establish an orchard and produce pistachios: San Joaquin Valley South 2008, Bessou, C. et al., 2012. LCA applied to perennial cropping systems: a review focused on the farm stage. The International Journal of Life Cycle Assessment, 18(2), pp.340–361. Available at: http://link.springer.com/index/10.1007/s11367-012-0502-z [Accessed January 29, 2013]. British Standards Institution (BSI), 2011. PAS 2050: 2011 Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Services, London, UK. Available at: http://clients.squareeye.net/uploads/brompton/documents/PAS2050.pdf [Accessed February 18, 2014]. Cambria, D. & Pierangeli, D., 2011. A life cycle assessment case study for walnut tree (Juglans regia L.) seedlings production. The International Journal of Life Cycle Assessment, 16, pp.859–868. Available at: http://www.springerlink.com/index/10.1007/s11367-011-0323-5 [Accessed October 12, 2011]. Centre, E., 2008. Ecoinvent Data v2.0. Coltro, L. et al., 2009. Assessing the environmental profile of orange production in Brazil. The International Journal of Life Cycle Assessment, 14(7), pp.656–664. Available at: http://www.springerlink.com/index/10.1007/s11367-009-0097-1 [Accessed January 6, 2012]. Connell, J.H. et al., 2012. Sample Costs to Establish an Almond Orchard and Produce Almonds: San Joaquin Valley North Sprinkler Irrigation, Davis, CA. Connell, J.H. et al., 2006. Sample Costs to Establish an Orchard and Produce Almonds: Sacramento Valley Lowvolume Sprinkler, Davis, CA. Duncan, R.A. et al., 2006. Sample Costs to Establish an Orchard and Produce Almonds: San Joaquin Valley North Flood Irrigation, Davis, CA. Duncan, R.A., Verdegaal, P.S., Holtz, B.A., Doll, D.A., Klonsky, K.M., et al., 2011. Sample Costs to Establish an Orchard and Produce Almonds: San Joaquin Valley North Flood Irrigation, Davis, CA. Duncan, R.A., Verdegaal, P.S., Holtz, B.A., Doll, D.A., Klonsky, K.A., et al., 2011. Sample Costs to Establish an Orchard and Produce Almonds: San Joaquin Valley North Micro Sprinkler Irrigation, Davis, CA. Freeman, M.A., Klonsky, K.A. & Moura, R.L. De, 2003. Sample Costs to Establish an Almond Orchard and Produce Almonds: San Joaquin Valley South Flood Irrigation, Davis, CA. Freeman, M.W. et al., 2003. Sample Costs to Establish an Almond Orchard and Produce Almonds: San Joaquin Valley South Micro-Sprinkler Irrigation, Davis, CA. 770


Freeman, M.W. et al., 2008. Sample Costs to Establish an Almond Orchard and Produce Almonds: San Joaquin Valley South Micro-Sprinkler Irrigation, Davis, CA. GEI Consultants & California Institute for Energy and Environment, 2010. Embedded Energy in Water Studies Study 1 : Statewide and Regional Water-Energy Relationship, Grant, J.A. et al., 2007. Sample costs to establish a walnut orchard and produce walnuts: San Joaquin Valley north, microsprinkler irrigation., Hester, S.M. & Cacho, O., 2003. Modelling apple orchard systems. , 77, pp.137–154. Kendall, A. et al., 2012. Greenhouse Gas and Energy Footprint of California Almond Production, Modesto, CA. Kendall, A., 2012. Time-adjusted global warming potentials for LCA and carbon footprints. International Journal of Life Cycle Assessment, 17(8), pp.1042–1049. Klein, G. & Krebs, M., 2005. California’s Water – Energy Relationship, Kroodsma, D. a & Field, C.B., 2006. Carbon sequestration in California agriculture, 1980-2000. Ecological Applications, 16(5), pp.1975–85. Available at: http://www.ncbi.nlm.nih.gov/pubmed/17069388. Marland, G. & Schlamadinger, B., 1995. Biomass fuels and forest-management strategies: How do we calculate the greenhouse gas emissions benefits? Energy, 20(I). Micke, W.C. & Kester, D.E., 1997. Almond growing in California. ISHS Acta Horticulturae, 470, pp.21–28. Milà i Canals, L., Burnip, G.M. & Cowell, S.J., 2006. Evaluation of the environmental impacts of apple production using Life Cycle Assessment (LCA): Case study in New Zealand. Agriculture, Ecosystems & Environment, 114(2-4), pp.226–238. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0167880905005256 [Accessed July 20, 2011]. Monselise, S.P., 1986. Handbook of Fruit Set and Development, Boca Raton, Florida: CRC Press. Mordini, M., Nemecek, T. & Gaillard, G., 2009. Carbon & Water Footprint of Oranges and Strawberries: A Literature Review, Mouron, P. et al., 2006. Life cycle management on Swiss fruit farms: Relating environmental and income indicators for apple-growing. Ecological Economics, 58(3), pp.561–578. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0921800905003411 [Accessed December 28, 2011]. Overend, R.P., 2004. Thermochemical Biomass Gasification Technologies and Products. Page, G. et al., 2011. Modeling Carbon Footprints of Organic Orchard Production Systems to Address Carbon Trading : An Approach Based on Life Cycle Assessment. HortScience, 46(2), pp.324–327. Pavley, F. & Nunez, F., 2006. Assembly Bill No. 32: The Global Warming Solutions Act, Sacramento, California. PE International, 2009. GaBi 4. Six, J. et al., 2004. The potential to mitigate global warming with no-tillage management is only realized when practised in the long term. Global Change Biology, 10(2), pp.155–160. Available at: http://doi.wiley.com/10.1111/j.1529-8817.2003.00730.x [Accessed July 18, 2011]. USDA Office of Global Analysis, 2013. Tree Nuts : World Markets and Trade, Washington, DC. Wallace, H.N. & Leland, R., 2007. USDA Project RCGG-2006-CA-02 “Promoting and Sustaining California Rural Cooperative Development”: Feasibility of a California Energy Feedstock Supply Cooperative, Williams, R.B., Jenkins, B.M. & Kaffka, S., 2008. An Assessment of Biomass Resources in California , 2007 DRAFT REPORT, Xiloyannis, C., Montanaro, G. & Dichio, B., 2011. Sustainable Orchard Management , Fruit Quality and Carbon Footprint. In Proceedings VIIth IS on Kiwifruit. pp. 269–274.

771

This paper is from:


8-10 October 2014 - San Francisco

Rita Schenck and Douglas Huizenga, Editors American Center for Life Cycle Assessment

The full proceedings document can be found here: http://lcacenter.org/lcafood2014/proceedings/LCA_Food_2014_Proceedings.pdf It should be cited as: Schenck, R., Huizenga, D. (Eds.), 2014. Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector (LCA Food 2014), 8-10 October 2014, San Francisco, USA. ACLCA, Vashon, WA, USA. Questions and comments can be addressed to: [email protected]

ISBN: 978-0-9882145-7-6