Maple Syrup Industry Research Articles

Experimental and computational comparison of freeze-thaw-induced pressure generation in red and sugar maple.

Sap exudation is the process whereby trees such as sugar (Acer saccharum Marsh.) and red maple (Acer rubrum L.) generate unusually high positive stem pressure in response to repeated cycles of freeze and thaw. This elevated xylem pressure permits the sap to be harvested over a period of several weeks and hence is a major factor in the viability of the maple syrup industry. The extensive literature on sap exudation documents competing hypotheses regarding the physical and biological mechanisms that drive positive pressure generation in maple, but to date, relatively little effort has been expended on devising mathematical models for the exudation process. In this paper, we utilize an existing model of Graf etal. (J Roy Soc Interface 12:20150665, 2015) that describes heat and mass transport within the multiphase gas-liquid-ice mixture in the porous xylem tissue. The model captures the inherent multiscale nature of xylem transport by including phase change and osmotic transport in wood cells on the microscale, which is coupled to heat transport through the tree stem on the macroscale. A parametric study based on simulations with synthetic temperature data identifies the model parameters that have greatest impact on stem pressure build-up. Measured daily temperature fluctuations are then used as model inputs and the resulting simulated pressures are compared directly with experimental measurements taken from mature red and sugar maple stems during the sap harvest season. The results demonstrate that our multiscale freeze-thaw model reproduces realistic exudation behavior, thereby providing novel insights into the specific physical mechanisms that dominate positive pressure generation in maple trees.

The Physicochemical Characterization and In Vitro Digestibility of Maple Sugar Sand and Downgraded Maple Syrups.

The maple syrup industry generates substandard syrups and sugar sand as by-products, which are underused. In this study, we conducted a comprehensive analysis of the physicochemical composition of these products to assess their potential for valorization. Using HPLC analysis, we measured sugar and organic acid content as well as total polyphenol content using the Folin-Ciocalteu method. Additionally, we evaluated the in vitro digestibility using the TIM-1 model. We showed that the composition of ropy and buddy downgraded syrups is comparable to that of standard maple syrup, whereas sugar sand's composition is highly variable, with carbohydrate content ranging from 5.01 mg/g to 652.89 mg/g and polyphenol content ranging from 11.30 µg/g to 120.95 µg/g. In vitro bioaccessibility reached 70% of total sugars for all by-products. Organic acid bioaccessibility from sugar sand and syrup reached 76% and 109% relative to standard maple syrup, respectively. Polyphenol bioaccessibility exceeded 100% during digestion. This can be attributed to favorable extraction conditions, the breakdown of complex polyphenol forms and the food matrix. In conclusion, our study demonstrates that sugar sand and downgraded maple syrups exhibit digestibility comparable to that of standard maple syrup. Consequently, they hold potential as a source of polyphenols, sugar or organic acids for applications such as industrial fermentation or livestock feeds.

Influence of Forester Traits and Advising Approaches on Landowners’ Intention to Follow Recommendations About Maple Sugarbush Management among Sap Producers in Wisconsin

Abstract The maple syrup industry has growth potential in the United States. Foresters can help expand the maple syrup industry by supporting private forest management decisions to improve maple tree health and sap production. This study examined the influence of advice solicitation, active listening, and forester traits (i.e., expertise, confidence, trustworthiness, shared forestland values) on outcomes of professional advice about maple syrup production and sugarbush management. Regression models were used to analyze data from a survey targeted at Wisconsin maple syrup producers (n = 149). Compared with unsolicited advice, advice outcomes were more positive when landowners actively sought it, although advice solicitation had a stronger influence on perceived quality of advice than advice utilization. Landowners evaluated advice more positively and had greater intention to use the advice when the forester actively listened to them. Perceiving positive traits in the forester has the strongest impact on landowners’ evaluations and adoption of advice. Study Implications: By examining the role of forester traits, giving (un)solicited advice, and active listening in affecting private forest landowners’ perceptions and use of advice about maple syrup production and sugarbush management, this study informs the design of training programs aimed at equipping foresters with effective communication skills. To achieve optimal communication outcomes, foresters should tactfully create the perception that the landowner requested their advice, such as by eliciting questions and encouraging landowners to explain their management motivations. Further, foresters should demonstrate expertise, show confidence, build trust, and create compatible management philosophies with the landowner by acknowledging the landowner’s perspectives.

Size and scope decisions of Maine maple syrup producers: A qualitative application of theory of planned behavior

Maple syrup production represents a prominent form of ton-timber forest production across the northeastern United States and Canada. Similar to farmers, maple syrup producers face complex size and scope decisions about the size or product diversification of their operation. Drawing upon 24 semi-structured interviews with small- and medium-sized producers in Maine, we apply the Theory of Planned Behavior (TPB) to identify factors contributing to producers’ size and scope decisions, including common challenges they face in achieving optimal size and scope. We find that attitude and perceived behavioral control guided by economic, personal, environmental and communal factors, contribute to size and scope decisions with minimal influence from perceived norms. Major challenges for maple syrup producers in achieving optimal size and scope include lack of capital to invest in technology upgrades and equipment, difficulty in finding additional accessible sugar and red maple stands, and lack of access to commercial kitchen facilities. We suggest future research, policy and management recommendations in addressing these challenges. These findings can help inform outreach and policy strategies to support the viability and sustainability of the maple syrup industry as well as be extended to other non-timber forest production practices.

A Changing Climate in the Maple Syrup Industry: Variation in Canadian and U.S.A. Producers’ Climate Risk Perceptions and Willingness to Adapt Across Scales of Production

Maple syrup production (“maple sugaring”) is an important cultural and economic activity in eastern Canada and the northeastern United States (U.S.A.). Climate change is a concern for maple producers because maple sugaring is dependent upon climate for both sap sugar content as well as for the specific patterns of freezing and thawing in springtime needed for sap flow. Meanwhile, the maple industry itself is in transition: historically, maple sugaring has been a small-scale seasonal activity, but today large producers tap thousands of trees, contributing to a widening gap in production volumes and production practices between small- and large-scale producers. Drawing on original survey data from 354 maple producers in Canada and the United States we ask how attitudes towards climate change risks and adaptation strategies differ between smaller-scale and larger-scale producers. Findings suggest that small-scale, medium-scale and large-scale maple producers have different perceptions of climate change risks, report different impacts of climate change on maple sap yields, and have different levels of willingness to use adaptation strategies ranging from tapping more trees to adopting new production technologies. In multivariate ordered logistic regression models controlling for producer age, education, and political affiliation, we consistently find the strongest correlates of attitudes towards climate change risks—and the willingness or ability of producers to adopt different adaptation strategies—are country of residence (with preferred adaptation strategies varying across Canada versus the U.S.A.) and producer scale (with larger producers adopting more adaptation strategies). We conclude that more detailed and up-to-date information on the different types of maple operations—including effects of climate change on maple sugaring and available adaptation strategies across geographies and across scales of production—is needed to help maple producers, maple producer associations, and policymakers understand how the maple industry is evolving and how best to prepare for the future.

A two-dimensional heat transfer model for predicting freeze-thaw events in sugar maple trees

Freeze-thaw cycles, where temperatures fluctuate above and below 0 °C, are the cause of elevated stem pressures that drive sap flow from within the sugar maple. This temperature-dependency has historically limited the production of maple syrup to select regions of North America. The plantation method of sap harvesting (which uses densely planted saplings instead of mature trees) now raises the possibility of a New Zealand-based maple syrup industry. In this study, a transient 2D heat transfer model was developed to predict freeze-thaw events in trees, and thereby evaluate potential plantation locations based on their climate. The heat transfer phenomena which have been modelled are bulk thermal diffusion, diffusion across discrete wood layers, convection, infrared radiation and solar radiation. Through experimental validation the model was found capable of predicting temperatures in real-life trees with high accuracy. Sensitive parameters were the bark absorptivity and sapwood diffusivity. Simulation results also indicate that the frequency of freeze-thaw cycles increase dramatically in saplings, as compared to mature trees, making maple syrup production potentially viable in locations that would otherwise fail when using traditional methods.

Composition and Properties of Maple Sap, Concentrate, and Permeate

Reverse osmosis is used widely in the maple syrup industry to concentrate maple sap and increase the overall efficiency and profitability of syrup production. Sets of samples from maple producers utilizing a range of sap concentration levels were collected and analyzed to provide a portrait of the physicochemical properties and chemical composition of maple sap, concentrate, and permeate across a single production season. The results reinforce that reverse osmosis functions essentially as a concentration process, without significantly altering the fundamental proportions of sap constituents.

In This Issue: A Smörgåsbord of Fresh Applied Research Papers

First paragraph: Sometimes you just have to improvise. We received such a strong response to our call for manuscripts on food system planning that we decided to squeeze a group of excellent additional papers on the topic into this winter issue. Starting out the issue, however, are a number of exceptional open-call papers. We begin with Assessing the Growth Potential and Economic Impact of the U.S. Maple Syrup Industry, by Michael Farrell and Brian Chabot. In honor of one of North America's unique seasonal foodways, this paper will remain open access (freely accessible even without a subscription) through April 2012....

Assessing the growth potential and economic impact of the U.S. maple syrup industry

This paper addresses the growth potential of the U.S. maple syrup industry. It outlines the number of potentially tappable maple trees and the economic impact of utilizing more of these trees for syrup production. U.S. producers currently tap 0.4% of all potentially tappable maple trees, with the highest percentage tapped in Vermont, at 2.94%. Two scenarios are analyzed for how production and consumption could grow together: (1) if each state tapped 2.94% of its available trees and consumed all of the syrup locally among its residents; and (2) the number of taps needed in each state to provide 2.6 ounces (76.9 ml) per person from sources. Based on these analyses, states with the greatest potential to increase local production and consumption of pure maple syrup include Connecticut, Michigan, New York, Ohio, and Pennsylvania. Strategic marketing efforts are necessary to help maple producers take advantage of the growing demand for local, healthy, and organic food.

Influence of Demographic Characteristics on Production Practices within the Ohio Maple Syrup Industry

Abstract Maple syrup production contributes approximately $5 million annually to Ohio's economy and provides supplemental nontimber forest product income for forestland owners. To better understand the factors that influence this important nontimber forest industry in Ohio, including producer heritage, producer age, sap collection methods, size of maple operation, and educational programming, we conducted a detailed survey of all known Ohio maple syrup producers (761 total producers). Over 80% of producers responded to the survey (620 respondents), making our analysis one of the most extensive of a maple industry in North America. In general, most maple operations in Ohio are part-time, family-based enterprises and over 25% of Ohio's maple producers are of Amish heritage. Although we estimate that there are over 400,000 taps in the state, the typical sugarbush is relatively small—the average sugarbush is 27 ac in size and over a third of the operations have fewer than 100 taps. Chi-square analyses did reveal several significant (α = 0.05) associations among producer characteristics. Although Amish producers were significantly younger and had significantly larger operations than their English or non-Amish counterparts (P < 0.001), a higher proportion of English producers reported using tubing collection systems than Amish producers (P = 0.031). Additionally, while larger maple operations tended to use tubing systems more frequently (P < 0.001), we did not detect a significant association between sap collection method (bucket versus tubing) and producer age (P = 0.169). Finally, English producers tend to be older. Older producers (>53 years old), producers using tubing collection systems, and producers with more than 250 taps were significantly more likely to participate in Ohio State University (OSU) Extension educational programming (P ≤ 0.05). These results suggest significant relationships among producer demographics and the characteristics of maple operations in Ohio, and future OSU educational programming should be tailored to reflect these important relationships.

Maple Syrup Production in Ohio and the Impact of Ohio State University (OSU) Extension Programming

Abstract The maple syrup industry in Ohio, which ranks fifth in total production in the United States, is comprised primarily of small family owned operations that are served by The Ohio State University (OSU) Extension system. We evaluated the effectiveness of OSU Extension educational programming designed to improve sugarbush and sugarhouse management through a survey administered at the three 2004 Ohio Maple Days workshops. Most survey respondents indicated that after attending past maple syrup workshops they implemented changes that were relatively simple and inexpensive; however, most indicated they are interested in learning more about technologies that increase production and maple syrup quality.

““Pure”” Maple Syrup?

This article examines the organic maple syrup industry in Canada, providing personal anecdote, a brief history of maple production and the underlying practice and philosophy of the organic movement as it applies to maple products. Often thought as inherently organic, modern, industrial maple syrup production includes a number of ways in which concerns may be raised for environment, sustainable farming practices or human health. Through interviews and research, the article presents some possible responses organic practices can make to such concerns, while also questioning whether organic maple production is everything it claims to be. The troubling and continued use of paraformaldehyde by the maple industry, though outlawed in both the U.S. and Canada, is raised, as are the accountability and inspection standards of regulatory bodies, both in conventional and organic maple production. The article concludes with the efforts at sustainability and diversity as practiced by an organic maple farm in New Brunswick and offers the author's personal views on the subject of sustainability and the merits of traditional methods of maple production.

Recurrent Hypothenar Hammer Syndrome: An Unusual Presentation

Upper extremity ischemia is a relatively rare phenomenon. A case of recurrent, surgically correctable, acute digital ischemia in a worker in the maple syrup industry is presented. The present case illustrates the importance of recognizing occupational exposure to risk factors. A review of the differential diagnosis, clinical work-up and literature surrounding acute vascular occlusion of the hand and upper extremity is presented.

Economic impact of the 1998 ice storm on the eastern Ontario maple syrup industry

Partial equilibrium analysis was used to characterize the economic impact of the 1998 ice storm on the maple syrup industry in Eastern Ontario. Stochastic simulation is used to generate interval estimates of damages. We compare government expenditures on assistance programs to the estimated industry losses. Total losses to the industry in terms of changes in producers' surplus and capital losses for the baseline scenario were estimated to be $5.5 (± $0.5) million. Extensive sensitivity analysis was conducted. Losses were estimated to be $4.7 (± $0.4) million if recovery takes place faster than in the baseline scenario. Losses were estimated to be $7.1 (± $0.4) million when recovery takes longer than in the baseline case. Direct government expenditures on ice storm assistance programs to this industry were approximately $7.3 million. The relevance of this type of analysis to the development of natural disaster relief policies is discussed. Key words: disaster assistance, eastern Ontario, economic, ice storm, maple syrup, producers' surplus

Assessing the Characteristics of the Maple Syrup Industry in Pennsylvania to Aid in the Development of Extension Programs

Assessing the Characteristics of the Maple Syrup Industry in Pennsylvania to Aid in the Development of Extension Programs

Off the treadmill? Technology and tourism in the north American maple syrup industry

The contrast between the nostalgic pictures on maple syrup packaging and sophisticated technologies actually used in the sugarbush and sugarhouse suggests disjunctures between image and practice in the contemporary North American maple syrup industry. This paper argues that although evidence of a “technological treadmill” exists within the maple syrup industry, as it does in other rural production sectors, such a trend is incomplete due to the increasing importance of consumption-based activities and concerns in the countryside. In response to the interests of tourists, second home owners and other increasingly influential non-producer groups, “traditional” maple enterprises persist, demonstrating a logic and appeal unaccounted for by treadmill theory. By addressing growing consumer concern about the appearance of the rural landscape, the health of the environment, and the quality of food, these “traditional” maple practices can provide distinct advantages for producers over technological modernization. The tension between technology use and tourism in the maple syrup industry offers insights about the role of small-scale specialty agriculture for sustainability in rural areas of advanced industrial countries undergoing social and economic change.