Research Update from the UVM Proctor Maple Research Center
Back by popular demand! Abby van den Berg will share results and progress from various research projects on maximizing yields and sustainability at the UVM Proctor Maple Research Center.
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Back by popular demand! Abby van den Berg will share results and progress from various research projects on maximizing yields and sustainability at the UVM Proctor Maple Research Center.
Because the impacts on yields of early tapping strategies, with or without subsequent rejuvenation, are likely to be affected by weather conditions which can vary widely from year to year, controlled experiments over multiple years are required in order to more fully assess whether any of these strategies result in greater yields than tapholes made during the standard spring sap flow period, or whether any increases in yield would be sufficient to compensate for the increased costs associated with implementing them. Thus, we conducted a multi-year, controlled experiment to assess the yields of several early tapping strategies, with and without subsequent rejuvenation, relative to the yields of standard spring tapholes.
In recent years, research at Cornell University’s Uihlein Maple Research Forest has looked at ways to maximize maple sap production through tapping practices such as spout selection, re-tapping and timing of tapping.
This aim of this project was to determine whether early spout and dropline deployment before tapping could be used while maintaining good sanitation levels and high sap yields.
Black Walnut (Juglans nigra) is a tree to consider tapping, and Butternut (Juglans cinerea) has similar characteristics and can produce syrup. When considering tapping, however, it is good to understood that walnut trees and not just maples with compound leaves and big edible nuts. Walnuts have anatomical and physiological characteristics that affect tapping and syrup making.
In response to injury from wounds such as tapholes, trees initiate processes to compartmentalize the affected area in order to prevent the spread of infection by disease- and decay-causing microorganisms beyond the wound, and to preserve the remaining sap conducting system (Shigo 1984). This results in the formation of a column of visibly stained wood above and below the wound, and the affected zone is rendered permanently nonconductive to water and nonproductive for sap collection. These processes, along with effects from microbial activity, are responsible for the gradual reduction in sap flow from tapholes over the course of the production season. There has been recent renewed interest in strategies which attempt to extend the standard sapflow season or increase overall yields through the “rejuvenation” of tapholes. As part of a multi-year experiment to investigate the yields and net economic outcomes of several taphole longevity strategies, we conducted an experiment to investigate the volume of NCW generated in response to two of these strategies.
Annual data on US maple production.
Nanofiltration and Reverse Osmosis are membrane concentration processes originally used by maple syrup producers to preconcentrate the sap to a moderate °Brix level (8–16 °Brix). The purpose of this study is to evaluate the potential of new membrane technology to concentrate maple sap to ultra-high °Brix and to investigate the effect of this concentration on the chemical composition and physical properties of final sap concentrate. Maple sap was concentrated up to 42 °Brix using two industrial membrane units. The contents of main solutes increased with the °Brix of concentrates depending on the specific rejection rate of the membranes tested. A slight and significant decrease was observed in the availability of some solutes such as K+, Mn++ and polyphenols in ultra-high-concentrated sap. However, the apparent organoleptic and physical properties of these concentrates have not been altered. According to the results of this, the new membrane process allows to produce ultra-high °Brix concentrate of maple sap with interesting properties. However, further works have to be performed on this technology to more precisely determine the highest °Brix level that will minimise the affect on chemical composition and properties of concentrated sap and the corresponding maple syrup.
How does a tree respond to the wound created by a taphole, and what does that mean for future sap production?
Explains how sap flows in trees and the impact that tapping has on subsequent years’ sap flow.