UVM Proctor Page


Sap flow, wounding and compartmentalization in maple

Timothy D. Perkins, Abby K. van den Berg, and Mark L. Isselhardt | June 23, 2021



Why the sap may not always flow well in the early season

Timothy D. Perkins, Abby van den Berg, Brendan Haynes | May 7, 2021

UNDERHILL CTR., Vt.—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.

First, trees are big and can have a large amount of thermal inertia (resistance to change).

By that we mean that tree temperature is buffered and will not always respond quickly to changes in air temperature.

Whereas air temperature can rise quickly during the day, it takes a while for the large mass of wood to warm up, particularly if it has been very cold prior to a warm period. MORE ]


Getting it right. Tapping tips for higher sap yield

Dr. Tim Perkins & Dr. Abby van den Berg | January 21, 2021

UNDERHILL CENTER, Vt.—Tapping. It isn’t as easy as simply drilling a hole in a tree.

Getting a good taphole in a good location is critical to achieve high yields.

Start with a sharp bit designed specifically for maple tapping, and sharpen or replace it after drilling about 2,500 holes.



Vermont researchers downplay fall tapping

Peter Gregg | November 10, 2020

UNDERHILL CTR., Vt.—Thinking about tapping this fall? Don’t bother.

That’s the message from Abby van den Berg, a research scientist at the Proctor Maple Research Center in Underhill Center, Vt. who hosted a compelling webinar on the topic last month.

“Generally speaking from a yield perspective, the data suggests fall tapping is not the best idea, especially factoring in all the extra things involved,” she said.

Dealing with extensive freeze and thaw cycles, tapping five feet in the air to account for winter snows in northern regions were just two of the big hassles that come with tapping extra early.



Stay away from the dead wood when tapping say Vermont researchers

Paul Post | October 20, 2020

UNDERHILL CTR., Vt.—Stay away from the dead wood.

Sugarmakers should maintain a large amount of clean, conductive wood in their trees, which will make sure the tree has a functional water transport system and is at relatively low risk of disease and decay.

That was the message from industry expert Abby van den Berg, University of Vermont research associate professor and assistant director of the Proctor Maple Research Center.

She was the host “Tapping Practices to Optimize Sustainability and Yields,” a webinar hosted by the Virginia Tree Syrup Program last month.

“But it also means we have a high probability of hitting clean, conductive wood when we tap,” van den Berg said. “That means we’re going to maintain sustainability of yields as well.”

Promoting healthy, radiant growth of trees is the underlying basis for ensuring maple production’s long-term success and profitability. MORE ]


Zoom maple! UVM offering fall series of maple education seminars online

Peter Gregg | September 16, 2020

MORRISVILLE, Vt.—Time for virtual maple.

This fall University of Vermont maple specialists will will continue their series of online webinars focused on business decision-making and forestry practices.

Sugarmakers across the U.S. are invited to learn about the best ways to integrate business management and sugarbush management for a thriving maple enterprise that targets profits and forest health.

Topics will include sap yields, sugarbush forestry, tubing systems, sap-only enterprises, sugarbush appraisal and more.


Tapholes – Straight or Slanted? The sap doesn't care

T.D. Perkins and W.T. Bosley, University of Vermont Proctor Maple Research Center | June 10, 2020

UNDERHILL CTR., Vt.—Straight or slanted? The sap doesn’t care the angle of your spout.

Historically it was recommended that tapholes be drilled at a slight angle to allow sap to run out to reduce freeze heaving of spouts and to reduce sap souring in the taphole.

Starting shortly after the introduction of the “small” spout (19/64”, 5/16”), maple equipment manufacturers started to recommend that tapholes be drilled straight in.

The most common reason for this was stated that it avoided the creation of oval tapholes. MORE ]


Rental rates and leases to right size your business

Mark Cannella, UVM Extension | April 14, 2020

MORRISVILLE, Vt.—Getting to at least 5,000 taps and utilizing rented trees may be the key to economic viability, according to new research from University of Vermont Extension.

Getting a maple business to a profitable scale is a primary goal for commercially-minded producers seeking meaningful income from their business.

A large equipment investment is needed to run a modern and efficient maple enterprise.

The prospect of purchasing more forestland may not be financially feasible for everyone that seeks to expand their enterprise.

Renting taps from other landowners can be a good approach to access more woods when a land purchase is not immediately possible. MORE ]