==== Front PLoS One PLoS One plos PLOS ONE 1932-6203 Public Library of Science San Francisco, CA USA 10.1371/journal.pone.0287691 PONE-D-23-03462 Research Article Earth Sciences Seasons Spring Biology and Life Sciences Agriculture Crop Science Crops Vegetable Crops Biology and Life Sciences Organisms Eukaryota Plants Brassica Broccoli Biology and Life Sciences Organisms Eukaryota Plants Vegetables Broccoli Engineering and Technology Transportation Biology and Life Sciences Nutrition Diet Food Medicine and Health Sciences Nutrition Diet Food Earth Sciences Seasons Winter People and places Geographical locations North America United States Earth Sciences Seasons Changes in the supply chain outcomes of food regionalization, 2007–2017: Broccoli in the eastern United States Changes in the supply chain outcomes of food regionalization, 2007–2017 https://orcid.org/0000-0003-4985-7016 Dai Bingyan Conceptualization Data curation Formal analysis Investigation Methodology Project administration Software Validation Visualization Writing – original draft Writing – review & editing 1 * Gómez Miguel I. Conceptualization Formal analysis Funding acquisition Investigation Methodology Project administration Resources Software Supervision Validation Writing – original draft Writing – review & editing 1 https://orcid.org/0000-0002-9715-6268 Atallah Shady S. Methodology Software Validation Writing – original draft Writing – review & editing 2 Björkman Thomas Data curation Funding acquisition Validation Writing – original draft Writing – review & editing 3 1 Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY, United States of America 2 Department of Agricultural and Consumer Economics, University of Illinois Urbana-Champaign, Champaign, IL, United States of America 3 Horticulture Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States of America Badi Ibrahim Editor Libyan Academy, LIBYA Competing Interests: The authors have declared that no competing interests exist. * E-mail: bd393@cornell.edu 29 6 2023 2023 18 6 e02876916 2 2023 10 6 2023 © 2023 Dai et al 2023 Dai et al https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Local and regional food supply chains are gaining increasing support from public and private sectors for their contributions to economic development and promoting sustainability. However, the impacts of regionalization are not well understood. We employ a spatial-temporal model of production and transportation to evaluate the supply chain outcomes of a decade-long process of food regionalization for fresh broccoli in the eastern United States (US). Our results indicate that eastern broccoli supply chains displaced products sourced from the western US and met over 15% of the annual demand in eastern markets in 2017. We find that total broccoli supply chain costs and food miles increased in the period 2007–2017. Nevertheless, eastern-grown broccoli has contributed to reducing regional food miles in the eastern region (from 365 miles in 2007 to 255 miles in 2017) and experienced only modest increases in supply chains costs (a 3.4% increase, compared to a 16.5% increase for broccoli shipped from western US) during the same period. Our results provide valuable information for policymakers and the fresh produce industry interested in promoting regional food supply chains. http://dx.doi.org/10.13039/100005825 National Institute of Food and Agriculture 2016-51181-25402 Gómez Miguel I. This work was funded by the USDA’s National Institute of Food and Agriculture through the Specialty Crops Research Initiative under award number 2016-51181-25402. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Data AvailabilityAll relevant data are within the paper and its Supporting Information files. Data Availability All relevant data are within the paper and its Supporting Information files. ==== Body pmcIntroduction Local and regional food supply chains are essential for agricultural and rural economic development in the United States (US) [1]. They offer new marketing opportunities for farmers and food businesses in response to growing consumer demand for locally/regionally grown foods [2]. Policymakers and food businesses are increasingly supporting local and regional supply chains as a means for improving economic, environmental and social outcomes [3–5]. The US Department of Agriculture (USDA) has invested over $1 billion in more than 40,000 on local and regional food supply chain projects between 2009 and 2015 [2], and food policies have increasingly supported the expansion of these supply chains to meet growing consumer demand for local foods [6]. Despite the growing importance of local and regional food supply chains, little has been done to measure their realized (or ex-post) economic and environmental impacts, particularly in fresh produce. An exception is Clancy et al. [7] which mapped regional supply chains in the northeastern US for various products including apples, cabbage, milk, and potatoes, among others. To fill this gap, we employ a spatial-temporal model of broccoli production and transportation to evaluate and compare the realized economic and environmental outcomes of a decade-long process (2007–2017) to develop the fresh broccoli supply chain in the eastern US. We solve for cost-minimizing production levels and derive seasonal transport patterns between supply and demand locations. Our analysis measures changes in supply chain costs, food miles, and the share of eastern-grown broccoli in the US eastern market between 2007–2017. Previous literature has focused on challenges and opportunities of local/regional food supply chains and on ex-ante economic and environmental impacts based on simulations. For example, research shows that a key challenge for local/regional food supply chains is their ability to be cost competitive [8–10]. Also, earlier research using simulation (ex-ante) approaches suggests that the economic and environmental impacts of localization vary across products. For example, Atallah et al. [11] showed that increasing food regionalization may reduce total broccoli supply-chain costs and reduce food miles and the associated greenhouse gas emissions. In contrast, Nicholson et al. [12] found that the regionalization of dairy supply chains increases the total distance traveled by fluid milk with attendant increases in supply-chain costs. Broccoli provides an excellent opportunity to assess selected economic and environmental impacts of regionalizing fresh produce supply chains. California and Arizona, which produce over 90 percent of the country’s fresh broccoli [13], face long-term concerns about water availability to support water-intensive crops such as broccoli [14]. Meanwhile, new broccoli varieties suitable for production along the eastern seaboard have enabled the emergence of the broccoli supply chain in this region [11]. From 2007 to 2017, total broccoli acreage in the US eastern region increased by 60% while acres planted in the western US increased by nearly 1% (Table 1) [15, 16]. This rapid expansion provides a unique opportunity to study the evolution of a regional food supply chain over a ten-year period. 10.1371/journal.pone.0287691.t001 Table 1 Estimated US Broccoli acreage from 2007 to 2017. Location 2007 base Acres 2017 Acres % Change Maine 5,205 5,948 14.27 New York 400 634 58.50 Penn 183 947 417.49 Virginia 551 411 -25.41 North Carolina 187 590 215.51 South Carolina 750 886 18.13 Georgia 219 316 44.29 Florida 600 3,000 400.00 New Jersey 139 489 251.80 Maryland 35 34 -2.86 Total Eastern 8,269 13,255 60.30 California 106,271 109,423 2.97 Arizona 11,869 9,329 -21.40 Total western 118,140 118,752 0.52 Source: Estimates from eastern broccoli project director and USDA-NASS census of Agricultural in 2007 and 2017. Our results indicate that eastern broccoli supply chains displaced products sourced from the western US and met over 15% of the annual demand in eastern markets in 2017. We find that total broccoli supply chain costs and food miles increased in the period 2007–2017. Nevertheless, eastern-grown broccoli has contributed to reducing regional food miles in the eastern region, from 365 miles in 2007 to 255 miles in 2017. Moreover, eastern-grown broccoli experienced only modest increases in supply chains costs (a 3.4% increase, compared to a 16.5% increase for broccoli shipped from western US) during the same period. Our findings provide valuable information for policymakers and fresh produce businesses interested in promoting regional supply chains in the US. Grower-packer-shippers can benefit from the identification of supply chain configurations that can improve the economic and environmental performance of seasonal fresh produce in the easter seaboard. The methods and lessons from studying broccoli may apply to other fresh produce crops that are consumed nationally, produced consistently year-round in the western US, and potentially expandable to other regions with new varieties, while still constrained by seasonality. Examples of such specialty crops are cabbage, cauliflower, carrots, celery, chicory, endives, grapes, strawberries and lettuce, among others. Materials and methods Production and transportation model We employ a spatial-temporal optimization model of production and transportation to compare the economic and environmental outcomes of the US eastern broccoli supply chain in 2007 and 2017. A production-transportation model allows us to analyze spatial and seasonal changes in the US broccoli supply chain, while accounting for two major characteristics: (1) fresh broccoli is perishable and seasonal, and (2) though fresh broccoli is consumed nationally, 92% of the crop is produced in California [13]. We parameterize the model with 2007 and 2017 data to solve for the production and transportation patterns that minimize total production and transportation costs in these years. Then, we compare supply-chain costs, market share and weighted average source distance (WASD) for the eastern broccoli system and conventional broccoli system and compare eastern supply chain flows in 2007 and 2017 for each season. Broccoli supply, demand, and transportation data The production and transportation model requires supply, demand, and transportation data. Supply data include yield estimates, unit production costs, and land available for broccoli production at each supply location. Data pertaining to demand are seasonal volumes demanded at each regional market location. Data pertaining to transportation includes distances between supply locations and demand markets, and seasonal unit transportation costs at each supply location. Modelled supply locations include ten fresh broccoli production regions in the eastern US, two western US producing regions (California and Arizona), and imports from Mexico and Canada (Table 2) for a total of fourteen broccoli supply regions. The fresh broccoli production regions in the eastern US are Maine, New York, Pennsylvania, Virginia, North Carolina, South Carolina, Georgia, New Jersey, Maryland, and Florida. We employ production cost estimates and yields in 2007 from recent regional broccoli crop budgets [9]. We updated yield estimates and adjusted 2017 production costs with changes in labor wages between 2007 and 2017 at each supply location using data from US Census Bureau and US Department of Labor [17, 18]. We used regional broccoli acreage estimates from USDA vegetable summary in 2007 and 2017 [15, 16] and confirm them with estimates from agricultural extension personnel in various Land Grant universities. 10.1371/journal.pone.0287691.t002 Table 2 Estimated US Broccoli imports from Mexico and Canada in 2007 and 2017.   2007 2017 Change % Change Import (1,000 21lb.-boxes) Mexico Spring 1,672 7,056 5,385 322 Summer 763 3,211 2,448 321 Fall 2,209 4,748 2,538 115 Winter 3,579 7,510 3,930 110 Annual 8,224 22,525 14,301 174 Canada Spring 112 179 66 59 Summer 51 81 30 59 Fall 148 120 -28 -19 Winter 240 190 -50 -21 Annual 552 570 18 3 Source: Estimates from USDA-ERS Data by Commodity-Imports and Exports in 2007 and 2017. The model has thirty-three demand nodes. We use metropolitan statistical areas (MSAs) to define demand locations in the eastern US. Demand is allocated to MSAs, and the state geographic centers based on population levels [19] and USDA’s per capita disappearance for fresh broccoli in both 2007 and 2017 [20]. Supply and demand quantities are measured in 21-lb broccoli boxes. For distances between production locations and demand nodes, we use the US state spatial distance matric in [21]. We use USDA’s quarterly agricultural refrigerated trucking rates [22, 23] and distances between supply locations to demand sites to calculate seasonal transportation cost for each supply location. To calculate shipment costs from Mexico, we use data from the Mexico Transport Cost Indicator Report [24, 25] and assumed the entry port is Pharr, Texas. Model formulation We followed the integrated production-transportation model employed in Atallah et al. [11] and solved for optimal fresh broccoli production levels and transport patterns in 2007 and 2017 respectively, using each year’s corresponding data. The model is structured as a mixed integer linear programming problem as follows: Minimize∑iI∑kKPCOSTi*XPi,k+∑iI∑jJ∑kKTCOSTi,j,k*DISi,j*XTi,j,k (1) Subjectto:∑jJXTi,j,k≤XPi,k (2) ∑iIXTi,j,k≥DEMANDj,k (3) XPi,kYIELDi≤LANDi,k (4) The objective function (1) is to minimize total supply chain costs, which include total production costs for all supply locations and total transportation costs from all origins to demand locations. The model solves for two decision variables, XPi,k and XTi,j,k, where XPi,k is the optimal production level at supply location i in season k and XTi,j,k is the optimal quantities transported from supply location i to demand location j in season k. PCOSTi is the average total unit production cost ($/box) in each supply location i and TCOSTi,j,k is the average total unit transportation cost ($/mile/box) from supply location i to demand location j in season k. DISi,j (miles) is the distance between supply location i to demand location j. In order for the production and transport patterns to be feasible, they must simultaneously satisfy three constraints: (1) broccoli shipped from supply location i to all demand locations j in season k cannot exceed production level at supply i in season k (Eq 2); (2) broccoli shipped to demand location j in season k from all supply locations i have to at least satisfy the demand level (DEMANDj,k) at each demand location j in season k (Eq 3); (3) land (LANDi,k) used to produce broccoli should not exceed the available land at supply location i in season k, where YIELDi is the supply location’s average broccoli yield (Eq 4). We use the weighted average source distance (WASD), or food miles, a measure commonly used in food system studies [26], to calculate a single distance figure that combines information on the distances from producers to consumers and the amount of product transported. We calculate eastern grown WASD (EWASD), mainstream sourced WASD (MWASD), and national WASD (NWASD) using the definitions in Eqs 5, 6, and 7. The calculations allow for the comparison of the food miles for two different broccoli supply chains (eastern supply chain and western supply chains) in eastern markets and to understand their changes from 2007 to 2017. EWASD=ΣiEORIGΣjEDESTΣkSEASDISi,j*XTi,j,kΣiEORIGΣjEDESTΣkSEASXTi,j,k (5) MWASD=ΣiMORIGΣjEDESTΣkSEASDISi,j*XTi,j,kΣiMORIGΣjEDESTΣkSEASXTi,j,k (6) NWASD=ΣiORIGΣjEDESTΣkSEASDISi,j*XTi,j,kΣiORIGΣjEDESTΣkSEASXTi,j,k (7) EWASD is the average distance from eastern growers to eastern markets. MWASD is defined as the average distance from western growers, including California, Arizona, Mexico, and Canada, to eastern markets. NWASD represents the average distance from all domestic broccoli growers and imports to eastern markets. We also measure how the shares of eastern-produced broccoli and transported quantities in eastern markets change seasonally and annually in 2007 and 2017. We calculate the share of eastern-grown broccoli in East Coast markets as follows: Eshare=ΣeEORIGΣfEDESTΣkSEASXTi,j,kΣiORIGΣjEDESTΣkSEASXTi,j,k (8) Results We use fresh broccoli production levels and transportation patterns in 2007 and 2017 to calculate changes in supply chain costs, market share of eastern-grown broccoli in eastern markets, and food miles for the western- and eastern-grown broccoli in eastern markets in the US. We also report seasonal eastern supply chain flows for 2007 and 2017 (Fig 1 to Fig 8). 10.1371/journal.pone.0287691.g001 Fig 1 US eastern broccoli supply chain flows in spring 2007. 10.1371/journal.pone.0287691.g002 Fig 2 US eastern broccoli supply chain flows in spring 2017. 10.1371/journal.pone.0287691.g003 Fig 3 US eastern broccoli supply chain flows in summer 2007. 10.1371/journal.pone.0287691.g004 Fig 4 US eastern broccoli supply chain flows in summer 2017. 10.1371/journal.pone.0287691.g005 Fig 5 US eastern broccoli supply chain flows in fall 2007. 10.1371/journal.pone.0287691.g006 Fig 6 US eastern broccoli supply chain flows in fall 2017. 10.1371/journal.pone.0287691.g007 Fig 7 US eastern broccoli supply chain flows in winter 2007. 10.1371/journal.pone.0287691.g008 Fig 8 US eastern broccoli supply chain flows in winter 2017. Changes in the supply-chain costs Results indicate that, in 2007, the landed costs (i.e., the costs of producing and transporting broccoli to eastern US demand locations) of a 21 lb. -box of broccoli produced in the East Coast were higher than a box of broccoli sources from the West Coast (Table 3). However, the per box cost of eastern-grown broccoli increased only modestly between 2007 and 2017, and was lower than the landed cost of a box of broccoli sourced from the West Coast in 2017. The landed costs for eastern-grown broccoli increased from $13.90/box to $14.37/box between 2007 and 2017, a 3% increase. In contrast, the landed cost of a box of broccoli sourced from the West Coast increased from $13.36/box to $15.57/box in the same period, a 17% increase. The average supply-chain costs of fresh broccoli to meet demand in the eastern US, which combines broccoli from all eastern region states and mainstream regions (West Coast and imports), increased by 14% in 2017 (Table 3). 10.1371/journal.pone.0287691.t003 Table 3 Changes on supply-chain costs in US eastern markets. 2007 2017 Change % Change Supply-chain costs ($/box) Average supply-chain costs of all sourced broccoli     Spring 14.22 15.19 0.97 7     Summer 14.32 15.69 1.37 10     Fall 13.00 15.53 2.53 19     Winter 12.26 15.16 2.90 24     Annual 13.45 15.39 1.94 14 Supply-chain costs of eastern-grown broccoli     Spring 13.35 13.66 0.31 2     Summer 14.02 14.81 0.79 6     Fall 14.06 14.88 0.83 6     Winter 11.99 13.06 1.07 9     Annual 13.90 14.37 0.48 3 Supply-chain costs of mainstream sourced broccoli     Spring 14.14 15.37 1.23 9     Summer 14.39 15.86 1.47 10     Fall 12.57 15.75 3.18 25     Winter 12.27 15.36 3.10 25     Annual 13.36 15.57 2.21 17 Source: Authors’ calculations based on the optimization model. The supply-chain costs of eastern-grown broccoli in 2007 varied across different seasons. During winter, the supply-chain costs for eastern-grown broccoli are the lowest at approximately $12 per box. Florida was the only supply location producing broccoli in winter 2017 on the East Coast and it was solely meeting local demand. Eastern-grown broccoli is more costly per box in the summer and fall season, at around $14 per box. As in 2007, the supply-chain costs in 2017 varied across different seasons, with an increase in costs observed in all seasons. As more land acreage was allocated to broccoli production in eastern US in 2017, eastern-grown broccoli was transported to more local and regional markets on the East Coast, which has contributed to the increased costs. The supply-chain costs of broccoli sourced from western US and imports were lower in the fall and winter seasons than in the spring and summer seasons in 2007. However, in 2017, these seasonal differences in supply chain costs for mainstream-sourced broccoli were almost non-existent. Changes in the share of eastern-grown broccoli in the eastern US Our results indicate that with a 60% increase of broccoli acreage in eastern regions between 2007 and 2017, the annual share of eastern-grown broccoli to meet demand in this region increased from 12% to 15% in this period (Table 4). Eastern-grown broccoli gained market share primarily in spring and winter, 6.5 and 6.7 percentage points, respectively. In contrast, the market share of eastern-grown broccoli decreased slightly in the summer and fall seasons (0.6 and 2.8 percentage points, respectively). The amount of broccoli shipped from eastern suppliers to East Coast demand locations increased substantially over the ten-year span. The largest change occurred in the seasons with increased market share (spring and winter). Winter shipments were up by 435% and spring shipments were up 232% (Table 4). Shipments within the eastern regions increased even in the seasons in which market share declined. Summer shipments were up by 21% and fall shipments were up 14% (Table 4). 10.1371/journal.pone.0287691.t004 Table 4 Changes on broccoli shipments to meet eastern US demand, 2007–2017.   2007 2017 Change % Change Market share of eastern-grown broccoli (%)     Spring 4.00 10.53 6.53 n/a     Summer 16.36 15.73 -0.63 n/a     Fall 28.87 26.03 -2.84 n/a     Winter 2.05 8.70 6.65 n/a     Annual 12.48 15.02 2.54 n/a Transported eastern-grown broccoli quantities (1,000 21lb.-boxes)     Spring 306 1,016 710 232     Summer 1,237 1,500 264 21     Fall 2,041 2,323 282 14     Winter 158 847 689 435     Annual 3,741 5,686 1,945 52 Source: Authors’ calculations based on the optimization model. Changes in eastern broccoli supply chain flows, 2007–2017 The expansion of broccoli production in the eastern US is associated with the spatial reorganization of the broccoli supply chain. In this section we present our findings regarding product flow changes in the eastern US between 2007–2017 for each season. The changes in product flows are presented in Table 5 and in Figs 1–8. 10.1371/journal.pone.0287691.t005 Table 5 Changes on seasonal broccoli flows (1,000 21lb.-boxes) from eastern locations and mainstream (West Coast and import) locations to eastern markets in 2007 and 2017.   2007 2017 Demand locations Eastern supply Mainstream supply Eastern supply Mainstream supply Spring Charlotte, North Carolina 0 246 104 222 Charleston, South Carolina 0 84 120 0 Augusta, Georgia 0 73 61 34 Gainesville, Florida 0 226 55 239 Summer Buffalo, New York 90 164 143 158 New York city, New York 146 1,366 184 1,660 Charlotte, North Carolina 16 227 52 270 Bridgeport, Connecticut 142 0 82 90 Hartford, Connecticut 119 0 128 13 Fall Buffalo, New York 90 148 143 138 Albany, New York 0 115 86 53 New York city, New York 823 592 549 1,176 Charlotte, North Carolina 0 227 104 197 Charleston, South Carolina 0 78 56 54 Durham, North Carolina 242 23 137 212 Gainesville, Florida 0 209 28 245 Winter Augusta, Georgia 0 74 55 41 Deltona, Florida 0 598 792 216 Source: Authors’ calculations based on the optimization model. Spring season According to the model, supply chain flows from eastern supply locations to eastern markets increased substantially between 2007 and 2017 (Figs 1 and 2). In spring 2007, 100% of broccoli shipped to Charlotte, NC came from the West Coast or was imported (Table 5). In contrast, by 2017, 32% of the broccoli shipped to this demand location came from the eastern US (Table 5). Another example of the increased importance of eastern-grown broccoli is the Charleston, SC demand location: In spring 2007, 100% of the broccoli shipped to Charleston, SC was sourced from outside the region; but by spring 2017, 100% of the broccoli shipped to this demand location was sourced from the eastern US. Similar shifts in sourcing occurred in Augusta, GA and Gainesville, FL. In 2007, both demand locations relied on western suppliers for 100% of their broccoli. However, spring 2017, eastern-grown broccoli represented 64% and 19% of total demand in Augusta and Gainesville, respectively. Summer season In contrast to the spring season, our results suggest modest product flow changes between 2007 and 2017 (Figs 3 and 4), with a few exceptions. The proportion of eastern-grown broccoli shipped to the Buffalo, NY demand location (NY1) increased from 35% in 2007 to 48% in 2017, an increase of 13 percentage points over the ten-year period. Conversely, in both Bridgeport, CT and Hartford, CT sourced 100% broccoli from eastern supply regions during summer 2007. However, by 2017, Bridgeport, CT (CT1) and Hartford, CT (CT2) sourced 52% and 9% of the broccoli from elsewhere. These two locations sourced their eastern-grown broccoli from Maine in both years. The results indicate substantial increases of broccoli grown in Maine and shipped to eastern demand locations from 2007 to 2017. Maine shipped more broccoli to other demand locations (MA 1, MA2, MA3, ME) with a shorter shipping distance. As a result, CT1 and CT2 increased sourcing from mainstream regions. These flow changes illustrate that not all demand locations in the East Coast increased regional sourcing. Fall season Figs 5 and 6 present the optimal broccoli flows in 2007 and 2017. Georgia was not a supplier of broccoli in 2007, but by 2017 it became a supplier to multiple MSAs in Florida. Other increases in eastern broccoli shipments to demand location in the region occurred in New York, North Carolina, and South Carolina. In 2007, all broccoli shipped in the fall to Albany, NY (NY2), Charlotte, NC (NC1), Charleston, SC (SC3) and Gainesville, FL (FL3) originated in mainstream supply locations (Figs 5 and 6). By 2017, however, these four demand locations sourced the majority of their broccoli from eastern states. For example, in 2017, 62% and 51% of broccoli demanded was from the eastern region in NY1 and SC3, respectively (Table 5). Nevertheless, some demand locations increased sourcing from outside the East Coast. For example, in New York City (NY3) and Durham, NC (NC2), the shares of eastern-grown broccoli decreased by 2017 resulting in over 50% of supplied broccoli to both cities coming from mainstream regions. Maine was the main broccoli supplier to eastern states for NY3 in 2007, but broccoli from this state was shipped to other demand locations located closer to production sites than New York City. Similarly, North Carolina and Virginia supplied 91% of broccoli demanded in Durham, NC; but by 2017, 60% of shipments came from California. These results suggest that not all demand locations have seen increases in eastern-grown broccoli in the fall season. Winter season In winter 2017, broccoli supply locations expanded to include Georgia (supplying to demand locations in the same state) in addition to Florida (Figs 7 and 8). Results also indicate broccoli quantities shipped from Florida and Georgia to eastern markets also increased substantially from 2002 to 2017. In 2007, 100% of broccoli demand in Augusta, GA (GA2) and Deltona, FL (FL2) was satisfied by mainstream regions (Table 5). By 2017, eastern-grown broccoli provided 58% and 79% of broccoli in Augusta (GA2) and Deltona (FL2), respectively. Changes in food miles The regional broccoli supply chains in eastern markets meet the expectation that the product travels less distances than broccoli coming from elsewhere. The largest broccoli production states, Maine and Florida, are about 1,600 miles apart. This distance is smaller than the one that separates Atlanta, GA and Salinas, CA (around 2,400 miles) or the one that separates it from Guanajuato, Mexico (around 1,650 miles). Atlanta, GA, as an example of a smaller market and long distances from the West Coast, makes a strong case that the difference in food miles needs to be quantified. The annual average distance travelled from eastern broccoli growers to eastern markets (365 miles) was far less than that from the out-of-region supply (2,533 miles; Table 6). The annual average distance from eastern broccoli regions to eastern markets decreased by 30%, from 365 miles in 2007 to 255 miles in 2017 (Table 6). This decrease is due to changes in product flows whereby eastern produced broccoli substituted some of the mainstream produced broccoli in eastern states. In contrast, the annual average distance of broccoli produced in mainstream source locations increased by 11%, from 2,533 miles in 2007 to 2,817 miles in 2017. 10.1371/journal.pone.0287691.t006 Table 6 Changes on weighted average source distance (WASD) travelled from different supply systems in US eastern markets in 2007 and 2017.   2007 2017 Change % Change WASD (miles) WASD of all national sourced broccoli (NWASD)     Spring 2,520 2,559 39 2     Summer 2,342 2,403 61 3     Fall 1,806 2,141 335 19     Winter 2,345 2,602 257 11     Annual 2,262 2,432 171 8 WASD of eastern sourced broccoli (EWASD)     Spring 111 130 20 18     Summer 383 287 -96 -25     Fall 408 324 -84 -21     Winter 158 160 2 1     Annual 365 255 -110 -30 WASD of mainstream sourced broccoli (MWASD)     Spring 2,625 2,845 220 8     Summer 2,726 2,798 73 3     Fall 2,373 2,780 407 17     Winter 2,391 2,834 444 19     Annual 2,533 2,817 284 11 Source: Authors’ calculations based on the optimization model. The average distance travelled from eastern broccoli growers to eastern markets exhibited seasonal variation in both 2007 and 2017. During the summer and fall, eastern-grown broccoli travelled longer distances compared to the spring and winter seasons, due to increased shipment volumes to more local and regional areas. In 2017, the average distance travelled from eastern broccoli growers to eastern markets decreased slightly during summer and fall seasons, while it increased during spring and winter due to changes in market share (Table 4). In addition, the average distance by broccoli sourced in mainstream locations also displayed seasonal differences. During the summer season, mainstream-sourced broccoli traveled the farthest distance (2,726 miles), while the distance travelled was relatively shorter during the fall and winter seasons (2,373 miles and 2391 miles, respectively). Notably, in 2017, mainstream-sourced broccoli travelled a longer distance during winter, exceeding the farthest distance travelled in summer 2007. Discussion The model solutions provide several insights regarding how the regionalization of the broccoli supply chains evolved over ten years (2007–2017) and its impacts on supply chain costs, market share, product flows and food miles. First, the model results show that eastern broccoli supply chains met over 15% of the annual demand in eastern markets in 2017, with modest increases in supply-chain costs. Despite eastern states having limited land with an appropriate climate to produce broccoli in spring and winter, market shares of eastern grown broccoli in these two seasons have increased by more than 6 percentage points from 2007 to 2017. One important advantage of sourcing eastern grown broccoli is the lower supply chain cost compared to the broccoli sourced from the mainstream system in 2017. Supply-chain costs of western-sourced broccoli are likely to rise due to increased land rent and limited irrigation water in western production regions due to rationing in times of drought. This is likely to increase incentives to further develop broccoli supply chains on the East Coast to attend this region’s demand. Second, the broccoli supply chain became shorter in 2017 compared with 2007, and its structure changed depending on demand sites and seasons. Not surprisingly, the average distance travelled from mainstream supply sites including the West Coast, Mexico, and Canada to eastern markets is much higher (2,817 miles in 2017), about eleven times as far as the distance travelled from eastern locations (255 miles in 2017). Thousands of miles saved could produce massive reductions in carbon emissions and pollution. Moreover, some supply chain flows in the eastern broccoli system changed unexpectedly. Changes in the share of eastern sourced broccoli and mainstream sourced broccoli supply for eastern demand locations differ across locations and seasons. The optimal supply chain structure we identified in this paper might provide insights for local and regional policies when designing desired distribution networks. This analysis also helps inform questions on the relationship between the mainstream and regional food supply chains. Our results demonstrate that the eastern broccoli supply chain has become integral to the entire national broccoli supply by complementing broccoli sourced from mainstream regions. Our cost-minimizing supply chain solution includes both mainstream and eastern locations shipping product to meet demand in the East Coast. Our results show that the eastern broccoli system has lower supply-chain costs and food miles, which will accumulate and become significant over time. As the dominant supplier, however, the mainstream broccoli system still accounts for high national market shares. Policymakers and businesses should focus on how to leverage the advantages of developing the eastern broccoli supply chain and its potential contribution to improve economic and environmental of the national supply chains. Policymakers should consider the impacts on the mainstream food system when designing policies to expand local and regional food systems. The model solutions might provide insights for structuring the future optimal supply system by giving the optimal magnitude, locations, and seasons. However, since the food system is more complex and outcomes such as social and environmental impacts should be taken into account to assess the performance of regional supply chains for fresh produce in general. Conclusions In this paper we employed a spatial-temporal model of production and transportation of the US broccoli sector to analyze changes and impacts of the evolving eastern broccoli supply chains from 2007 to 2017. The primary conclusion is that the eastern broccoli supply chain has gained market share during this period and has contributed to lower costs and food miles for broccoli consumers in the region. The increased regionalization in the period 2007–2017 modestly increased the total supply chain costs, moderating the substantial increases in production costs in supply locations outside the region, specifically in the West Coast. In addition, the food miles of broccoli produced in the east coast decreased substantially between 2007 and 2017 (from 265 miles to 255 miles per box). These positive trends and increasing market size also present opportunities for growers and food businesses to expand regional food production. Although the model is used to assess the US eastern broccoli systems, we believe that our model is generalizable and can be adopted to evaluate and track other regional supply chains for fresh produce. Our estimated decade-long economic and environmental effects of regionalization of the broccoli supply chains offers insights into the optimal planning and design of local and regional supply chains for policy makers and other stakeholders. Product flow reorganizations occur differently for each season and vary across demand locations in the Eastern US. Our results suggest that the eastern broccoli supply chain shows modest changes in summer and fall, while major flow changes occurred in spring and winter. Therefore, grower-packer-shippers and policymakers should carefully consider opportunities to regionalize supply chains, because the impacts vary by season, and location. Our findings are valuable to the fresh produce industry, policy makers and other stakeholders interested in promoting localization of supply chains. Nonetheless, our model has several limitations that deserve further investigation. First, fresh produce supply chains might be influenced by several supply disruptions, such as the water crisis in western US. Long-lasting droughts are driving the water shortages across much of the west and are likely to reduce crop yields, lead farmers to plant fewer acres and increase production costs for irrigation water, to reduce acreage, or to abandon production altogether. The spatial-temporal model can be expanded to evaluate the impacts of such disruptions and provide valuable information on optimal locations to replace production regions affected by disruptions. Such changes might increase broccoli production costs in traditional production areas on the West Coast. Researchers can use our transshipment model to identify the optimal eastern supply locations to meet national demand while minimizing the total production and transportation costs. Second, we assumed that broccoli acreage increases in the eastern states are a small fraction of total fresh vegetable acreages. Future research can include the crops that compete with broccoli for land in each eastern state and the opportunity costs of broccoli acreage expansion in the model. Third, our model does not consider East Coast consumer preferences for broccoli produced in the region. Future research can examine consumer preferences for regionally produced broccoli and the implications for economic and environmental outcomes. Finally, we focus on a specific commodity (broccoli) to illustrate the impacts of localizing fresh produce supply chains. Future studies can adapt our model to examine the impacts of regionalizing supply chains for other fresh produce sectors. Supporting information S1 Dataset (XLSX) Click here for additional data file. 10.1371/journal.pone.0287691.r001 Decision Letter 0 Badi Ibrahim Academic Editor © 2023 Ibrahim Badi 2023 Ibrahim Badi https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version0 27 Mar 2023 PONE-D-23-03462A decade later: Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United StatesPLOS ONE Dear Dr. Dai, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. 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Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. 10.1371/journal.pone.0287691.r002 Author response to Decision Letter 0 Submission Version1 15 May 2023 May 11th, 2023 Dr. Ibrahim Badi Academic Editor PLOS ONE Re: Re-submission Manuscript PONE-D-23-03462 for PLOS ONE Dear Dr. Badi, Thank you for the opportunity to revise and resubmit our manuscript entitled “Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United States” and for the thoughtful comments provided by you and the reviewers. We appreciate the time and effort that went into the review process. We have carefully considered the feedback provided by you and the reviewers and have made significant revisions to the manuscript. Reviewer 1 provided valuable feedback on the length and clarity of our abstract and introduction, as well as the presentation of our results. In response, we made substantial changes in most sections of the manuscript including the Abstract and the Introduction, Results, Discussion and Conclusion sections to make them clearer and more concise. We have also expanded future directions for research in the Conclusion section. Reviewer 2 provided a valuable comment regarding our interpretation of results regarding supply chains costs and food miles. In response, we addressed his/her concerns in the Discussion and Conclusion. Please see details of the changes we made in the manuscript in the response to each reviewer below. Regarding journal requirements, we have made the necessary changes to our manuscript in accordance with your request. Specifically: • In our Data Availability statement, in the original submission we did not specify where the minimal data set underlying the results described in our manuscript can be found. In response, we are now providing our data set, which will be included as supporting information files. • Regarding the copyright of map images in the original submission, we were unable to obtain permission from the original copyright holder. In response, we now provide replacement figures that comply with the CC BY 4.0 License. We used ArcGIS to create all the figures. Using ArcGIS maps in academic publications is permitted by the terms of use for ArcGIS static maps (https://doc.arcgis.com/en/arcgis-online/reference/static-maps.htm). We uploaded a new copy of supporting information, Figures 1-8 which we refer to in our text on page 29. • We have conducted a thorough review of our manuscript and can confirm that it adheres to PLOS ONE’s style requirements. Furthermore, we have carefully revised our reference list and can verify that it is complete and correct. My co-authors and I believe that the revisions we have made have substantially improved the quality of our manuscript. We have taken into consideration all of the comments and feedback provided by you and the reviewers and have carefully revised the manuscript accordingly. To help with the review process, we have attached both a marked-up copy that highlights the changes made to the original version and an unmarked version of our revised paper without track changes. We hope that this will assist in evaluating the changes that we have made. Thank you again for the opportunity to revise our manuscript. I look forward to hearing back from you soon. Sincerely, Bingyan Dai   Response to Reviewer # 1 Manuscript PONE-D-23-03462 “Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United States” Overview of response: Thank you for taking the time to review our manuscript and provide us with valuable and constructive feedback. Your comments helped us improve the quality of our manuscript, and we are grateful for your comments. In response to your comments, we revised the Abstract and the Introduction section to make them more concise, to the point, and to improve the clarity of exposition. In addition, we rewrote substantial portions of the Results section to clearly present our findings. Furthermore, in the Conclusion section, we now discuss limitations of the study and suggest areas for future research. You will find your original comments in bold and our response right below each comment. The article is topical. However, the following revisions may further improve the clarity a. The abstract and Introduction section are long. We agree with the reviewer. In response, we completely rewrote the Abstract and the Introduction section to clearly state the relevance of our research question, our approach to answering the research question, and the findings of our study. In doing so, we substantially shortened the Abstract and the Introduction section to improve the clarity of communication and the flow of the manuscript. Please see the new Abstract and the new Introduction section (pages 2-5). b. Please present the result section in a lucid way. Thank you for this comment. We agree that the Results section needs to be substantially improved. In response, we practically rewrote this section to clearly discuss our finding; to present more relevant detail on the cost, flows and food mile changes between 2007 and 2017; and to clearly and precisely interpret the model results. Please see the revised Results section (pages 10-19). c. Add few more future directions. This is an excellent suggestion. In response, we elaborated more on the discussion of future research directions. Specifically, we now discuss four areas for future research as follows (see new paragraph in page 22): 1) Fresh produce supply chains might be influenced by several supply disruptions, such as the water crisis in western US. Long-lasting droughts are driving the water shortages across much of the west and are likely to reduce crop yields, lead farmers to plant fewer acres and increase production costs for irrigation water, to reduce acreage, or to abandon production altogether. The spatial-temporal model can be expanded to evaluate the impacts of such disruptions and provide valuable information on optimal locations to replace production regions affected by disruptions. Such changes might increase broccoli production costs in traditional production areas on the West Coast. Researchers can use our transshipment model to identify the optimal eastern supply locations to meet national demand while minimizing the total production and transportation costs. 2) We assumed that broccoli acreage increases in the eastern states are a small fraction of total fresh vegetable acreages. Future research can include the crops that compete with broccoli for land in each eastern state and the opportunity costs of broccoli acreage expansion in the model. 3) Our model does not consider East Coast consumer preferences for broccoli produced in the region. Future research can examine consumer preferences for regionally produced broccoli and the implications for economic and environmental outcomes. 4) We focus on a specific commodity (broccoli) to illustrate the impacts of localizing fresh produce supply chains. Future studies can adapt our model to examine the impacts of regionalizing supply chains for other fresh produce sectors.   Response to Reviewer # 2 Manuscript PONE-D-23-03462 “Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United States” Overview of response: Thank you for taking the time to review our manuscript and provide us with valuable and constructive feedback. In response to your comment and the comments from other reviewer, we revised the Abstract and the Introduction section to make them more concise, to the point, and to improve the clarity of the exposition. In addition, we rewrote substantial portions of the Results section to clearly present our findings and clarify the results regarding costs and food miles. Furthermore, in the Conclusion section, we now discuss limitations of the study and suggest areas for future research. You will find your original comment in bold and our response right below each comment. The paper evaluates the supply chain outcomes of a decade-long process of food regionalization for fresh broccoli in the United States and found that eastern broccoli supply chains displaced product sourced in the western US, meeting over 15% of the annual demand in eastern markets in 2017. However, the results regarding supply-chain costs and food miles were not consistent with previous research which predicted that increasing localization of fresh broccoli would decrease total supply-chain costs and food miles in eastern markets. Thank you for this comment. The reviewer is correct that the results regarding supply-chain costs and food miles were not consistent with previous research which predicted that increasing localization of fresh broccoli would decrease total supply-chain costs and food miles in eastern markets. The national supply chain costs increased because the cost of west coast-grown broccoli increased substantially (from 13.36 $/box in 2007 to 15.57 $/box in 2017). However, we note that the costs of east coast-grown broccoli increased only modestly (from 13.90 $/box in 2007 to 14.37 $/box in 2017) (see Table 3). Therefore, we argue that east coast-grown broccoli has contributed to avoiding substantial cost increases for broccoli in this region. We now explain this clearly in the revised Discussion and in the Conclusion sections. Regarding changes in food miles, we agree that our discussion of results in the original submission was not clear. National food miles increased because the distances traveled by broccoli originated outside the east coast increased (from 2,533 miles in 2007 to 2,817 miles in 2017). Nevertheless, the distance traveled by east coast-grown broccoli decreased (from 365 miles in 2007 to 255 miles in 2017) (see Table 6). Therefore, east coast-grown broccoli has contributed to moderate the increase in food miles of the national supply chain shipping broccoli to the east coast region. We now explain this clearly in the revised Discussion and in the Conclusion sections. Attachment Submitted filename: Response to Reviewers.docx Click here for additional data file. 10.1371/journal.pone.0287691.r003 Decision Letter 1 Badi Ibrahim Academic Editor © 2023 Ibrahim Badi 2023 Ibrahim Badi https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version1 12 Jun 2023 Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United States PONE-D-23-03462R1 Dear Dr. Dai, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Ibrahim Badi, PhD Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #1: All comments have been addressed ********** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes ********** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes ********** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes ********** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes ********** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: I don't have any further comment. The authors have addressed the concerns raised earlier. The authors are requested for checking minor typos ********** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No ********** 10.1371/journal.pone.0287691.r004 Acceptance letter Badi Ibrahim Academic Editor © 2023 Ibrahim Badi 2023 Ibrahim Badi https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 21 Jun 2023 PONE-D-23-03462R1 Changes in the supply chain outcomes of food regionalization, 2007-2017: Broccoli in the eastern United States Dear Dr. Dai: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Ibrahim Badi Academic Editor PLOS ONE ==== Refs References 1 Office of Communication. On May 20, 2015, Secretary Vilsack spoke with delegations from 34 countries as part of the 10th Organization for Economic Cooperation and Development Conference, held in Memphis, Tenn. In his remarks, the Secretary reaffirmed his vision for comprehensive. Release No. 0142.15. U.S. Department of Agriculture; 2015. Available from: https://www.usda.gov/media/press-releases/2015/05/20/may-20-2015-secretary-vilsack-spoke-delegations-34-countries-part 2 Statement by Thomas Vilsack. U.S. Department of Agriculture; 2016. 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