An Initial Assessment of the Frequency of Maple Crop Failure in the U.S.
Some seasons sometimes produce a bountiful crop of maple syrup. In other years producers are considerably less lucky. Periodic failures of the maple crop happen.
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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.
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.
Drop and spout sanitation review
Considerable research has been conducted by the Cornell Maple Program and University of Vermont Proctor Maple Research Center on the effects of spout and tubing sanitation on improvements in sap yield and economics.
Temperature Compensation Chart for Maple Syrup Hydrometers
The University of Vermont Extension’s “New” temperature compensation chart syrup hydrometers. 
New Temperature Compensation Chart for Syrup Hydrometers
New Temperature Compensation Chart for Syrup Hydrometers developed by the University of Vermont Extension
Spout colors can affect sap temp at the taphole
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.
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.
A 20-Year Record of Syrup Production at UVM Proctor Maple Research Center from 2004-2023
he 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.
Cost of hitting stained wood when tapping
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).