Characterizing maple sap flows
Individual sap flow events are highly variable and dynamic, ranging from slow, weeping flows that last for days to short bursts of high flow that last for only a few hours.
Author: Haynes, Brendan
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Ask Proctor: How does Sap Move Near Tap Wounds
Because of the vertical orientation of the dominant anatomical feature of wood (vessels and fibers), sap within the stem of maple trees moves primarily in a vertical direction, either upward during as the tree is freezing/uptake phase or downward (mostly) during the thawing/exudation phase. When a tree is tapped, a zone of impermeable wood forms around the wood.
Total Yields From Red Maples
Many producers include red maples as crop trees without a second thought. And still many others will walk past red maples with a roll of tubing. Why the difference? Much of it arises from some lingering perceptions about red maples – that they produce lower yields or stop running earlier than sugar maples, or produce syrup with inferior flavor or that exhibits buddy flavor earlier than sugar maple.
Yields from Early Tapping and Taphole “Rejuvenation” Strategies
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.
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Open in new tab Wound Response to Taphole Rejuvenation Practices
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.
Why sap may not always flow well in early season
Maple producers know that when the temperature starts to rise in the spring, sap flows can’t be far behind. But when the weather starts to warm early in the spring and temperatures seem favorable for good sap flows, they are sometimes left wondering why the sap hasn’t started to run. There are several explanations for the disconnect between warm air temperature and a lack of flow during
the early season.