The importance of the cranberry to Massachusetts agriculture

The American cranberry, Vaccinium macrocarpon Aiton, is native to the US and southeastern Canada. Commercial cranberry production started in Cape Cod, Massachusetts in the early 1800s and Massachusetts was the number one grower of cranberries until 1998 when Wisconsin surpassed Massachusetts’ production. Cranberries continue to be Massachusetts’ number one commercial crop, bringing in almost $82.16 Million in sales in 2022.

The cranberry bog is a unique agricultural production system. In New England, cranberry vines grow in a monoculture within glacier-formed kettle bogs or artificially constructed bogs that have alternating layers of sand (from the cultural practice of sanding the bog every 2–5 years) and organic matter (from decomposition of the leaves and vines). Traditional kettle bogs have a layer of peat below the crop rooting zone that holds vast quantities of water, and carbon. Although cranberry bogs are labeled as wetlands under federal law, cranberry plants cannot withstand prolonged submersion in water while biologically active. Thus, commercial cranberry systems have systems of ditches, dikes, flumes, and pumps to regulate the flow of water on and off the bogs. Historically, cranberries were dry harvested with large wooden scoops and were used for fresh berry consumption. The modern, more efficient wet harvesting technique involves flooding the bog, mechanically raking the vines to free the berries, and collecting the floating berries. Wet harvesting has evolved with advances in water control structures and harvest mechanization.

Regional climatic changes that affect the ecology of the cranberry bog

A warmer climate presents a series of complications to the cranberry agroecosystem. Average annual air temperature has risen by 0.26°C (0.5°F) per decade since 1970, with winter temperatures increasing at a faster rate [8]. In Massachusetts air temperature is almost 2.0°C (3.6°F) higher than the average temperature between 1900 and 1960 (see Fig 1) [9, 10].

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Fig 1. Observed and projected changes (compared to the 1901–1960 average) in near-surface air temperature for Massachusetts.

The orange line represents observed data from 1900–2020. Modeled projected changes include a lower emissions scenario with temperatures at the end of the century reaching 5.0°F plus or minus a few degrees, and a higher emissions scenario with air temperature by 2100 reaching 11.0°F plus or minus a few degrees. Note. Reprinted from Massachusetts State Climate Summary 2022. NOAA Technical Report NESDIS 150-MA by Runkle et al. (2022) [10].

https://doi.org/10.1371/journal.pclm.0000350.g001

Cranberries are particularly susceptible to a warming planet; the plants require a certain number of “chill hours,” hours below 7.2°C (45° F). In fact, “abnormal blossoming has been observed to take place in Massachusetts when [cranberry] plants received less than 1,500 hours (~62 days) below 45°F during the winter” [11]. UMass Extension recommends that cranberries receive 1,500 chill hours to avoid crop failure. Former UMass Extension Director Carolyn DeMoranville (2009) stated that there are no low chill varieties of cranberries (p.73) [12]. A warmer climate advances flowering times in the spring and delays (red) color formation in the fall. Additionally, a warmer climate favors insect, weed, and pathogen population growth, all of which require additional chemical use in conventional growing systems [7, 13]. Unlike annual crops that are reseeded annually, providing growers with flexibility in planting practices and crop or variety choices, cranberry plants are perennial and a long-term investment for cranberry growers. This means that cranberry growers cannot easily migrate north to cooler climates, nor can they switch to more heat tolerant crops without taking a major financial loss.

Throughout the Northeast, precipitation has increased in total, has become more intense and more variable from year to year [9]. The ten-year interval of 2005 to 2014 was the wettest on the long-term record (1895–2020) with Massachusetts receiving the largest number of 2-inch precipitation events and on average 5.6 more inches of rain per year [10]. More water can mean more plant growth for both cranberry plants and weeds; however heavy precipitation events that flood bogs during times when the cranberry plants are least tolerant to saturation can injure plants. Warm and wet conditions can also lead to higher occurrence of plant disease, necessitating the need for additional fungicide applications. Seasonality of precipitation is also changing with more of the annual rainfall coming between November and April, and less between May and October [14]. Additionally, Massachusetts experienced extreme drought during 2016–2017 and in 2020 [10]. This all adds up to cranberry growing conditions becoming more complicated for growers, such that adaptation and application of sound growing strategies is growingly important for the success of this historic industry.

Extension as a “trusted group” in the cranberry socio-ecological network

Like all agricultural growers, cranberry growers operate in a “thoroughly socio-organizational” production network made up of various actors, both ‘social’ (e.g., fellow growers, Extension agents, pest control advisors, neighbors, conservation organizations, local politicians, etc.) and ‘natural’ (e.g., climate conditions, weather patterns, geography, water availability, pests, pathogens, pollinators, etc.), meaning they operate in a dynamic socio-ecological network [15]. Actors interact with one another to construct “networks of knowledge” that support truth claims about the world, particularly, in this context, about agricultural knowledge. This process of sharing experiences and knowledge among a group with similar experiences in agriculture creates a sense of trustworthiness among the networked actors [15–17].

Extension agents have been discussed in the literature as having a profound ability to help shape the knowledge frames of agricultural networks, having earned both the trust of growers as well as being recognized as experts with solutions to problems experienced by growers in the field or bog. By extension, we can argue trustworthiness in grower networks contributes to Extension’s success in disseminating knowledge that leads to particular forms of practice. Providing Extension agents with training in conservation techniques, for example, is identified as an important way to align grower behavior with sustainability practices due to their influence and perceptions of trustworthiness in the network [18–20]. Other research points to Extension as the principal agent capable of addressing “the tension between short-term maladaptive decision factors and longer-term sustainability imperatives” among growers [21]. Other studies argue that “Extension, promotion and marketing programs by government workers … can be positively related to adoption” of promoted environmental and agricultural practices [22–25].

With roughly 400 growers in operation in New England, the cranberry grower social network is both small and tight-knit. For example, too small for any company to produce machinery specific to the cranberry harvest, cranberry growers oftentimes design their own equipment, frequently sharing the equipment and fine-tuning designs with each other’s feedback [26]. The small size also translates into growers having ample opportunity to connect with the small number of Extension agents at the UMass Cranberry Station whose sole job is to help cranberry growers succeed in their production [7]. Gareau et al. [27] showed that the majority of Massachusetts cranberry growers view UMass Extension as an important (we may say trustworthy) actor in their social network. Additionally, Gareau et al. [27] found that cranberry growers who viewed UMass Extension and other cranberry growers as important to their network were more likely to feel worried about climate change than those who did not, but were less likely to view climate change as an existential threat. In this study, we thus aimed to understand the nature of the communication about climate change from UMass Extension.

Interplay between natural and social factors

Natural actors influence agricultural knowledge networks, necessitating that social actors adapt within their trust patterns in meaningful ways. Far from operating in isolation [7, 13, 15, 27], growers depend on trusted networks to make informed decisions in their fields or bogs. Understanding cranberry growers’ perceptions, adoption, and adaptation to climate-resilient practices requires examining trust and social networks [15], along with the cultural and institutional factors affecting grower decision-making [28, 29]. By adopting an integrated perspective that bridges the gap between the social and natural realms, researchers can better understand the factors influencing cranberry growers’ behavior and contribute to the development of effective, context-sensitive interventions aimed at fostering sustainable and climate-resilient agricultural practices [30, 31].

Taking seriously the concept of the co-construction of social and natural systems means emphasizing the importance of acknowledging the entanglements between human and non-human actors in cranberry production [32, 33]. These entanglements include the interdependencies between growers, Extension agents, and the broader ecological systems. Freudenberg et al.’s [34] critique of the nature/society divide in social theory encourages scholars to investigate socio-environmental dynamics that shape growers’ responses to climate-induced challenges.

Evidence suggests that growers can adopt adaptive and mitigating actions without engaging specific causation assumptions related to climate change. Growers may unconsciously adapt to climate change in their daily practices for various reasons. These reasons include observing shifts in weather patterns, responding to other agricultural stressors, relying on traditional knowledge or intergenerational experience, seeking to improve productivity and resilience, and implementing risk management strategies [35–45]. This is in line with previous studies that conclude growers’ decisions to adapt are dependent on their unique experiences and observations on their property, as well as their interpretations of changing weather and climate conditions [40, 41, 46, 47]. The urgency for sustainable practices has prompted some growers to adopt various adaptation strategies, such as using climate forecasting to reduce production risk and manage water resources [48–50]. However, whether cranberry growers adapt in similar ways remains an unanswered question.

Indeed, there is a research gap concerning the adaptation strategies employed specifically by cranberry growers in response to climate change. Investigating this area could provide valuable insights for the cranberry industry and contribute to developing tailored adaptation approaches for wetland agriculture systems more broadly defined.

Research questions

To understand the influence of social and natural factors on how cranberry growers are experiencing and adapting to climate change pressures, we addressed the following research questions:

1. How has UMass Extension engaged growers in conversations about climate change and adaptation over time?
2. How has anomalous weather influenced Extension’s communication about conditions and practices in cranberry growing over time?
3. How have changes in climate impacted cranberry production, and how are growers adapting?

Ethics statement

This research complies with ethical practices and was approved by the Boston College Institutional Review Board (Protocol numbers 12.139.01e and 12.139.01eA). Survey respondents were solicited to participate in the survey in two ways, either online or via hard copy. The online consent form explained the nature of the study prior to answering questions, and a hard copy of the consent form was provided as part of the survey form. Interviewees gave verbal consent prior to conducting each interview.

UMass Extension Cranberry Station newsletters

To characterize the explicit and implicit dialogue on climate change and adaptation disseminated from the UMass Cranberry Extension, we used monthly newsletters published by the station between 1974 and 2020. Issues published in 1974–2001 were acquired in physical form from the UMass Cranberry Station in Wareham, MA, digitized, and imported into NVivo for content analysis. Issues published from 2002–2020 were downloaded directly from the UMass Cranberry Station website and similarly uploaded into NVivo. We then performed both summative and conventional content analyses around themes of climate change, weather extremes, agrochemical use, cultural practices, and biological actors (insect pests, weed pests, pathogens, and bees). We summed the number of mentions of “climate change” and mentions of a “warming” climate versus language related to extreme weather conditions (“drought,” “hail,” “hurricane,” and “storm”) to characterize UMass Extension’s dissemination of knowledge around climate change impacts to cranberry production.

Regional climate data

The Blue Hill Observatory in Milton, MA, USA has recorded monthly temperature highs, lows, and means and total monthly precipitation since 1891 [51]. While most Massachusetts cranberry bogs are located 30–80 miles southeast of the weather station, the long-term dataset accurately characterizes climate trends in the entire state. We are interested in both the general trend of precipitation and temperature over time and the effects of anomalous temperature and precipitation months and years. Annual temperature has gotten increasingly warmer, with the warmest years on record occurring within the past decade. Precipitation has also been increasing, although there are more fluctuations between wet and dry years and precipitation events are becoming more concentrated. Long-term climate graphs of the region are available on the Blue Hill Observatory website [51].

Survey

To recruit cranberry grower participation in a survey, we aimed to reach the entire cranberry grower population (estimated at around 400) with a multi-pronged approach. The UMass Cranberry Station emailed the online survey solicitation to its member listserv in January, February, and April of 2016 and the authors ran a half-page advertisement with a link to the survey in the Cape Cod Cranberry Growers Association’s (CCCGA) Bogside newsletter from February to June of 2016. We also did two direct mailings of the survey advertisement in February and April and direct mailing with a hard copy of the survey and a return envelope with paid postage in November of 2016. Each successive mailing excluded growers who had already submitted responses. In total, we received 91 responses (23% response rate) between the dates of 31 January and 24 December 2016. The survey instrument is described in Gareau et al. [7, 27]. To characterize growers’ perceptions of climate change threats, we asked growers to rate the importance of the following pressures over the past 5 to 10 years: water scarcity, water competition, heavy precipitation, extended high temperatures in the summer, extended high temperatures in the fall, insufficient chill hours in the winter, importance of insect pests, importance of weed pests, and importance of disease. We asked a related question, “which of the following specific weather-related events severely impacted your cranberry production from 2010- present?” providing the choices, “high precipitation in a short amount of time, drought, summer heat wave (temperature above 90 for several days), warmer winter, hail or sudden frost event, and ‘other’.” Participants could choose more than one weather-related event.

We also asked cranberry growers two open-ended questions: “What has changed over the years to make it harder to prepare for weather-related events that impact your cranberry production?” and; “What has changed over the years to make it easier to prepare for weather-related events that impact your cranberry production?” For factors that make it harder to prepare for weather-related events, we coded responses into the following categories: large storms/increased rainfall, warmer than normal, inaccurate forecasting/information, unpredictability of the weather, reduced precipitation/drought, accessibility of water resources, frost, factors unrelated to weather or the environment, and nothing/no impact. For factors that make it easier to prepare for weather-related events, we coded responses into the following categories: better forecasting and information services, technology improvements, improvements to water infrastructure, wisdom that comes with experience, and unrelated to weather or the environment. Participants mentioned one or more factors for both questions.

Interviews with cranberry growers

We conducted 18 in-depth interviews with cranberry growers between 2012 to 2018. Some of the interviews were conducted by undergraduate and graduate researchers trained by the authors in research method techniques, others were conducted by the first author. The interviewers visited with cranberry growers, often at their bogs, to ask them about their bog management, the impact of climate change and weather-related events on their cranberry production, and their concerns and approaches to adaptation.

While the interview schedule was open-ended, interviewers asked pointed questions regarding the challenges faced by the Massachusetts cranberry industry, and how they are responding to environmental and social challenges such as water quality, climate change, and competition from future generations. Around fourteen pointed questions were asked, ranging from the history of each bog to the family or individual’s relationship to the bog, their predictions for the future in both social and environmental aspects, economic hardships, and their cultural aspects of cranberry farming that they find enticing. Interviews were conducted in a conversational manner with a loose interview guide, and participants were assured of anonymity through the use of pseudonyms. The interviews were digitally recorded, and consent forms (approved by the authors’ University Institutional Review Board) were used to inform all participants that, if agreeable to them, interviews would be recorded, transcribed, and used in future publications. After each interview, the recordings were analyzed using Dedoose [52] and NVivo software programs. Additionally, the researchers kept field notes journals to make observations on what was seen and experienced.

The 18 interviews conducted with cranberry growers, within a total population of 400, provide valuable context and depth to our survey data collected from 91 growers. The 18 interviewed growers and 91 surveyed growers were not mutually exclusive groups.

Data analysis

To examine how climate conditions have shaped UMass Extension’s communication on climate change and bog management to growers, we analyzed the UMass Cranberry Station’s monthly newsletter, together with historical weather data for the years 1974 to 2020 provided by Michael J. Iacono, Chief Scientist at The Blue Hill Observatory [51]. We calculated whether a given year’s total precipitation and mean temperature was anomalous by subtracting the monthly total precipitation and monthly average temperature data to the 10-yr mean value. We calculated the precipitation and temperature anomalies as the absolute deviation from the 10-year mean, a common method in anomaly assessments [53, 54]. The 10-year reference is defined by averaging precipitation and temperatures over specific years.

We used the word count of the newsletters as a control variable. Over 46 years, the newsletter has a general trend of getting longer. During that time span, the shortest newsletter contains 234 words, the longest 10,694 words. To change the largely different values to a common scale while keeping the differences in the ranges, we normalized the word count variable, resulting in obtaining normalized continuous word count data. Then, we cut the continuous word count variable evenly into 5 categories to make it useful as a control variable.

Next, we calculated how many times on average keywords were mentioned per newsletter issue, and then compared them across years with different climatic conditions. We examined the utilization of four main categories of agrochemicals: herbicides, insecticides, fungicides, and fertilizers. These chemical categories address various biological responses such as weed control, insect management, pathogen and fungus protection, disease prevention, as well as the safety of bees and other pollinators. To clarify, herbicides (e.g. Callisto) are used to control unwanted plants or weeds, insecticides (e.g. Chlorpyrifos) target insects that may harm cranberry crops, fungicides (e.g. Chlorothalonil) protect against fungal infections, and fertilizers (e.g. Phosphate) provide essential nutrients to support crop growth. We also investigated the broad category of weather challenges that includes the terms: frost, drought, extreme heat, winter kill, storm, and hail. Each broad category includes mentions of related keywords. For example, the keyword category of herbicides includes the word “herbicide” as well as specific brands of herbicides, similarly for the categories of insecticides and fungicides (see Codebook in the supplementary materials for details). In total, we assembled 14 dependent variables: 1) total chemicals; 2) total insect pests; 3) total weather challenges; 4) total weather; 5) total pollination; 6) total herbicides; 7) total insecticides; 8) total fungicides; 9) total bog management; 10) total weeds; 11) total pathogens; 12) total fruits; 13) total soils; 14) total social organization.

The categories for the dependent variables are ordinal, thus an ordinal logistic regression was preferable [55]. In this research, we employed ordinal logistic regression (OLR) models to investigate the associations between the temperature anomaly, precipitation anomaly, and the normalized word count in the newsletter and the total newsletter coverage of chemicals, weather challenge, soil, and bog management. OLR employs a proportional-odds cumulative logits model with ordered variables. Of the five response categories, “0 mention of the specific dependent variable” was coded as the reference category. Therefore, our equation was as follows:

Here, α_i is an intercept parameter, which could vary for different i, β is the vector of slope parameters, and it is the same for different levels (i) of the ordinal dependent variable. X are the independent variables, including the temperature anomaly, precipitation anomaly, and normalized word count. Y are the dependent variables, which measure the total newsletter coverage as measured by the five-point ordinal scale.

To test the relationship between growers’ experience of extreme weather events and their perception of the importance of climatic changes, we ran simple linear regressions using the survey data. For the variable selection, we used stepwise regression [56] as a method to add or remove variables from the model based on their statistical significance. The process begins with an initial set of predictors, typically chosen based on previous research or expertise in the area of study [57–59]. The process is then repeated, with the remaining variables, until all variables in the model have a p-value below a certain threshold (usually 0.05). Then, we used the same set of independent variables to predict the dependent variables. We used cross-validation and model assessment to ensure that the final models are robust and generalizable. The sample met the homogeneity of variance, independence, and normality assumption. Following the formula of

where y is the predicted value of the dependent variable (y) for any given independent variable (x) value. y including growers’ rate of extreme weather events in the last 5–10 years, from Q32-Q40, including water scarcity, competition for water, heavy precipitation, extended high temperatures in the summer, extended high temperatures in the fall, insufficient chill hours, insect pests, weed pests, disease. β0 is the intercept, while β1 is the regression coefficient. x is the independent variable. In this research, x including grower’s crop diversity—whether they just grew cranberries or have other crops or livestock in their farm management; Proportion of upland habitat in total land acre; total acres; Drought severely impacted your cranberry production from 2010- Present; Summer heat wave (temperature above 90 for several days) severely impacted respondents’ cranberry production from 2010- present. ∈ is the error term.

Information from a trusted knowledge network

UMass Extension started explicitly discussing climate change (or “global warming”) as a new phenomenon that would affect management options in 2007. Of the 168 newsletters published between January 2007 and December 2020, however, only 11 issues mention “climate change” or changes in weather patterns (see S1 Table). The narrative begins by emphasizing the potential effects of global climate change and the importance of understanding chilling requirements and dormancy, primarily focusing on temperature anomalies. The content then examines case studies illustrating the industry’s challenges due to changing weather patterns, discussing the consequences of record warm winters, drought, hail storms, and temperature fluctuations on yield, fruit quality, and pest vulnerability. As the narrative unfolds, it highlights the significance of research in mitigating climate change effects and mentions ongoing projects such as monitoring Putnam scale infestations and studying weather patterns’ impact on plant physiology. The need for further research in areas like predictive models for fruit rot and understanding extreme weather events is emphasized. The content offers recommendations for adaptation, including adjusting water management practices and refining cranberry frost prediction formulas. It concludes with an acknowledgment of the industry’s potential "new normal," emphasizing the importance of adaptation for sustainability in the face of warmer temperatures, late harvesting, and changing conditions.

Influence of anomalous weather on communication

Our analysis revealed a positive correlation between normalized word count and all dependent variables. This suggests that as the length of an article increases, so too does the breadth of coverage of key topics related to cranberry production. However, the rate of increase in coverage varies between these topics. For instance, we noted that a one-unit rise in normalized word count significantly increased the ordered log odds (B) by 1.702, leading to more comprehensive coverage of weather challenges, assuming other variables in the model were held constant. Similarly, in the context of bog management topics, an equivalent increase in normalized word count was associated with a marked increase of 3.134 in the log odds (B), enhancing the depth of coverage in the newsletter.

Despite infrequent direct communication on climate change and climate adaptation, we found that the independent variable, “anomalous monthly temperature” was a significant predictor of UMass Extension’s communication on total weather challenges (B = 0.158, p<0. 01). Meanwhile, anomalous monthly precipitation was negatively associated with total chemical mentions (B = -0.144, p<0.05). These results suggest that Extension is more responsive in communication to growers during months of anomalous temperature than months of anomalous precipitation (See Table 1).

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Table 1. Ordinal logistic analysis of the predictors of UMass Extension newsletter coverage.

https://doi.org/10.1371/journal.pclm.0000350.t001

We checked if ordinal logistic regression was a suitable method for analyzing our data by conducting a test of parallel lines, which examines whether the parameters for different orders are the same. The results indicate that the dependent variables are appropriate to be considered ordinal, with the exception of total mention of herbicides and fruit, which were found to be significant at a 0.05 level.

Importance of climate change impacts

Survey results.

Among a variety of environmental conditions, cranberry growers gave the highest importance to weed pests, insects, and disease (N = 90) (Fig 2). Of the weather or resource-related conditions, growers rated extended high summer temperatures, water scarcity, heavy precipitation, and extended high fall temperatures between 3.5 to 4.0 (of some importance). A notable outcome is that over 80% of respondents scored extended high temperatures in summer as important to very important (Table 2). Thus, cranberry growers rank extended high summer temperatures (i.e., heat waves) as the most important weather condition affecting their production. Insufficient chill hours in the winter scored lowest in importance (2.9) with only 30% of respondents rating the condition as important or very important.

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Fig 2. Average score on a Likert-scaled question to rate the importance of specific environmental conditions in recent years.

(N = 90).

https://doi.org/10.1371/journal.pclm.0000350.g002

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Table 2. Percentage of respondents who rated the provided environmental condition as important or very important.

https://doi.org/10.1371/journal.pclm.0000350.t002

When asked which weather-related events severely affected cranberry production from 2000–2010 (in the past decade) and from 2010 to the present (in the recent decade), the majority of respondents selected summer heat waves and drought for both time periods (Table 3). The percent of respondents who reported that high precipitation in a short amount of time severely impacted their yield dropped from 50.7% (2000–2010) to 39.1% in 2010-present.

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Table 3. Percentage of respondents who reported impactful weather events.

https://doi.org/10.1371/journal.pclm.0000350.t003

Table 4 presents results of regression analysis between independent variables of crop and animal diversity, total acres, proportion of upland habitat, experience with drought, and experience with summer heat wave with several dependent variables related to how growers ranked importance of different environmental conditions. We found a significant positive relationship between growers who cultivate more than one crop (i.e. cranberry) and growers who ranked water scarcity as important (B = 0.91, p<0.05). Growers who reported experiencing more drought during 2010 to the present were also more likely to rate as important the following conditions: water scarcity (B = 1.007, p<0.05) and extended high temperatures in summer (B = 0.419, p<0.01). Growers who reported being impacted by summer heat waves in recent years were also likely to rate extended high temperatures in the summer as important (B = 0.531, p<0.05).

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Table 4. Correlation coefficients between the independent predictor variables (column headers) and the dependent variables (rows) importance of environmental conditions.

https://doi.org/10.1371/journal.pclm.0000350.t004

Respondents provided a variety of responses to the open-ended question, “what has changed over the years to make it harder to prepare for weather related events that impact your cranberry production?” (Fig 3). Thirty-three percent of respondents mentioned a condition that did not relate to the weather or the environment, including old age, costs of production, government regulation, off-farm employment, and personal health circumstances, while 17% of respondents reported that nothing has changed that has made weather-related events harder to prepare for. Warmer than normal temperatures was reported by approximately 20% of the respondents. Large storms/increased rainfall was reported by 17% of the respondents as a condition that has made it harder to prepare for weather-related events that impact cranberry production. Illustrative responses to the aforementioned themes are reported in S2 Table.

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Fig 3. Percentage of responses (N = 36) to the open-ended question, “what has changed over the years to make it harder to prepare for weather-related events?”.

https://doi.org/10.1371/journal.pclm.0000350.g003

Adaptive strategies

Survey results.

Responses to the survey question, “what has changed over the years to make it easier to prepare for weather-related events?” provide some insight on adaptation strategies. We found high agreement around two main themes: better forecasting, and technology advances (Fig 4). The types of technological advances growers mentioned included automated irrigation systems, weather applications, and cell phones. Ten percent of respondents mentioned improving the water infrastructure of the bog to be able to better access and divert water. Illustrative responses of these themes are reported in S3 Table. In general, growers were optimistic about their ability to control bog conditions with more accurate weather information and technological advancements in bog management.

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Fig 4. Percentage of responses (N = 54) that answered the open-ended question, “What has changed over the years to make it easier to prepare for weather-related events?”.

https://doi.org/10.1371/journal.pclm.0000350.g004

Sixty-six percent of the growers who responded to the survey question, “which of the following management practices have you implemented on your bog in the last 5–10 years?” chose the option “Smart irrigation and/or frost alarm.” This technology uses soil moisture and air temperature sensors to trigger an automated irrigation system, which reduces the labor involved to check irrigation heads, turn on sprinklers, and monitor weather forecasts. Smart irrigation is responsive to the localized soil conditions and microclimate of the cranberry bog, helping farmers to conserve water while making spring frost management more manageable. Binary logistic regression analysis revealed that growers with more acreage (S4 Table) and who reported being impacted with summer heatwaves (S5 Table), were more likely to report adoption of modernized irrigation systems (B = 0.022, p<0.05; B = 1.339, p<0.05).

Optimism

While growers expressed concern about extreme weather, they also showed optimism for the future of cranberry production in Massachusetts, especially when it came to their own production. Growers rationalize that if cranberries are growing in regions with a warmer climate than their own, they can be grown successfully in their own region. Growers also consider the cranberry to be a resilient plant.

“William” (2018), for example, expressed optimism and resilience by highlighting the unique coastal conditions of Cape Cod that counteract some of the impacts of climate change:

It’s always been a little bit unique on the Cape [Cape Cod, MA]. So they’ll [referring to mainland growers] be colder in the winter and you’ve got the sea breeze keeping us a little warmer in the winter… So even if it warms up, it’s never going to be as warm as it is off-Cape… So I don’t see how it’s going to adversely affect the Cape growers. But off-Cape growers may have a different feeling, because they’re already hot now.

“Austin” (2012) demonstrated a "wait and see" strategy, with a willingness to adapt when necessary:

I haven’t seen global warming, let’s say climate change, hasn’t affected me that much. I don’t know, there are those that say the climate is getting warmer. I guess whatever you just said is close to true. But it hasn’t affected me yet.

“Margaret”, cranberry bog owner, and “Isaac,” the field manager of Margaret’s bog, both expressed confidence in the adaptability of cranberries to different climate conditions, emphasizing the resilience of both the plants and the growers to cope with changing temperatures and other environmental challenges:

There’s a lot that we can control even though there’s still a lot we can’t. … “If cranberries can grow in New Jersey… I don’t see that it will be a problem here. As long as we get cold nights, which we always do. We get more cold nights than New Jersey, right? (Margaret, 2018)

I don’t know about the weeds but I can tell you this, the cranberry is very adaptive to temperatures… And, the newer varieties that they’re planting around here, they’re doing very well. (Isaac, 2018)

Here, the interplay of social-natural relations in the cranberry growers’ lives, reinforced by the trusted UMass Extension in the knowledge network, has resulted in general confidence that a warmer climate can be approached with optimism for the cranberry industry in New England.

Limitations

This research acknowledges two primary limitations. Firstly, while a combination of online and hard copy survey methods was used to target a diverse demographic and reduce selection bias, there remains the possibility that not all viewpoints were representatively captured. Secondly, the survey and interview data, spanning from 2012 to 2018, might not entirely reflect current trends in cranberry growers’ attitudes towards climate change. Despite extensive research, no more recent, publicly accessible systematic data were found in this area. As a result, our study, while capturing a significant historical period, represents the most comprehensive analysis currently available, offering insights into the long-term adaptation strategies and perceptions of cranberry growers amidst climate variability.