Bark removal and taphole closure with arc-barb spouts
The Arc-Barb Spout (UVM Patent Pending) is designed with a shortened barrel to allow improved sap flow from the shallower, more productive sapwood zones in maple stems.
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The Arc-Barb Spout (UVM Patent Pending) is designed with a shortened barrel to allow improved sap flow from the shallower, more productive sapwood zones in maple stems.
We reported in a previous article (Does Color Matter?, The Maple News June/July 2018) that color influences the degree of solar warming of spouts during sunny, windless days and can impact sap yields.
Natural vacuum created in3/16” tubing has been a boon for many maple producers in stands where sufficient grade allows it to function properly. The column of sap moving downhill in 3/16” tubing doesn’t readily allow air bubbles to pass, but rather pushes them out of the system, creating a vacuum (Wilmot 2014, Perkins and van den Berg 2018). Unfortunately, several years of use have demonstrated that 3/16” tubing systems can be prone to clogging by microbial masses (Wilmot 2018, Perkins and vanden Berg 2019), especially at fittings (Childs 2019) where the internal diameter is greatly reduced.
The University of Vermont (UVM) Proctor Maple Research Center (PMRC) in Underhill, Vermont, has along history of research on sap production. Maple syrup has been made at PMRC since shortly after its founding in 1946, in part for research and in part for demonstration. Syrup production has always been an important component of the work of PMRC as it keeps the faculty and staff aware of the issues involved in sap collection and syrup production, it provides more of a “buy in” from producers when they understand that we face the same hurdles as they do each season, and the revenue gained from the sale of maple syrup helps to fund the operation.
Avoiding tapping near previous tapholes is a common practice in maple production. This is because previous wounds create a zone of stained wood that extends slightly wider and deeper than the taphole, but extends upwards and downwards, often reaching 6-12 inches in length in each direction, affecting a volume of wood approximately 50 times (range of 15-150X) larger than the volume of the taphole (vanden Berg et al. 2023).
Because of the lack of knowledge on this topic and the frequent questions we received about the proper practice, we implemented a study in the summer of 2022 to examine the single and interactive effect of spout deployment date and open verses closed drops on sap yield.
The outermost rings of wood in maple trees have the highest sap flow rates and have sweeter sap than the wood found deeper in the tree. We designed a spout that incorporates both a shortened barrel and a series of barbs along the shaft to anchor the spout tightly within the wood and bark tissues.
Ongoing research at the University of Vermont Proctor Maple Research Center over the past thirteen years has examined a variety of approaches to increases yield from 5/16” maple tubing systems on vacuum.
Maple sap tubing collection systems have undergone continuous evolution since being introduced. Over the past several decades, spouts in particular have changed considerably, with a marked shift towards smaller (1/4”, 19/64”, or 5/16”) spouts, developed and introduced by CDL.
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.