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.
Resource type: Research
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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.
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.
Innovations in Maple Sap Collection Systems: Reducing Clogging in 3/16” Tubing
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.
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.
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).
Sweet Talk: All Things Maple
This ongoing podcast features interviews with researchers and educators about topics related to maple production and marketing.
Net-Zero Maple Syrup
An examination of why and how maple sugarmakers can make their operations carbon-neutral.
2023 season barb spout results
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.
Why Does the Sap Stop Running After a Few Days if it Doesn’t Freeze Again?
Without a freeze, the flow of sap will continue to slow and eventually stop because there is no longer a difference between the pressure inside and outside of the tree. However, producers often observe an uptick in sap flow during the daytime over a few days. Why does this occur? Where did the extra sap come from? Typically, these short bursts of increased sap flow happen when the temperature warms over the next few days. The warm temperature causes gas bubbles in the wood fibers to expand and squeeze more water from the wood tissues, where it flows into the vessels and out through the taphole. This might occur for a couple of days, and eventually turn into slow weeping flows before ceasing entirely.