UW News

March 25, 2021

Video: Tasty options as researchers tap a new forestry product

UW News

Scientists from the University of Washington are testing the viability of making maple syrup in the Pacific Northwest. Long associated with Canada or Vermont, this sweet forest product that has graced many a breakfast table may be part of this region’s future.

A young woman holds a cup to catch clear liquid from a canister attached to a maple tree.

A student collects maple sap in Pack Forest.Kiyomi Taguchi / University of Washington

Washington maple syrup is made from the watery-looking sap of bigleaf maple trees, one of the most abundant native hardwood trees in the Pacific Northwest. Given the right winter weather conditions, bigleaf maples — even here in Western Washington — can be utilized for their sap. 

Researchers with the UW School of Environmental and Forest Sciences are proving this concept in a pilot project at the university’s Pack Forest near Eatonville, Washington. As part of a research initiative funded by the U.S. Department of Agriculture’s ACER program, they are producing syrup and measuring factors that might affect bigleaf maple and their sap. This winter, the project expanded to six additional sites across Western Washington, where private landowners were given seed grants to begin collecting sap on their properties.

“This is an exciting project,” said Indroneil Ganguly, project leader and associate professor in the School of Environmental and Forest Sciences. “We are on the cusp of a really, really big maple syrup industry in the Pacific Northwest.”

Winter 2019 was the first time that maple sap was collected at Pack Forest. The most productive time of year for sap collection is from about late-November to mid-February, when temperatures dip below freezing. Freezing conditions followed by a warm spell build pressure in the tree trunk. When the bark is drilled through and the tree is “tapped” — seen in this video with black plastic plugs that connect to delivery lines — the pressure forces maple sap out of the tree and down the tubes.

The “sugar shack” at UW’s Pack Forest.Kiyomi Taguchi / University of Washington

A building at Pack Forest known as the “sugar shack” houses the equipment that removes water from sap and boils it down, concentrating it and filtering the syrup before bottling. Gregory Ettl, UW forestry professor and director of the Center for Sustainable Forestry at Pack Forest, manages the syrup production and says it takes anywhere from 60 to 100 gallons of sap to make one gallon of the rich, brown syrup, depending on the sugar content of the sap. The clear maple sap collected from the UW site contains around 1% sugar.

Researchers are still measuring factors that might impact the trees and their sap. Some of the maples in the project are studied individually to see if tapping affects their health, and records are kept about how much sap each tree produces and how sugary it is. 

A unique aspect of this project is to give commercial value to a tree that is commonly seen by landowners as low value or undesirable, said Ganguly. Bigleaf maple are often abundant in areas bordering streams, known as riparian zones, where the state restricts clearing or logging. Maple trees in riparian zones play a critical role in maintaining bank stability, soil quality and shade, and are essential for keeping streams clean and suitable for fish habitat.

In a lush forest, some maples have canisters on their trunks, attached to each other by slender green tubes.

Pack Forest maple sap collection site.Kiyomi Taguchi / University of Washington

If maple syrup production in the Northwest can be proven viable, it could provide an additional source of income to landowners while leaving these maples essentially intact. In Washington state, about 50 percent of private forests (3.2 million acres) are owned and managed by small landowners, so providing these community members with a commercial incentive to try tapping maple sap in wooded areas by streams could have a significant environmental impact, the researchers said.

The UW team has already coordinated with six property owners in western Washington — ranging from Forks to Bellingham to Bremerton — where sites look promising for maple syrup production. These maple syrup entrepreneurs received, on an average, $5,000 to $10,000 of in-kind support in the form of sap collection equipment and labor to begin collecting maple sap. 

A bottle of maple syrup with a purple label sitting on a weathered wood tabletop.

A bottle of maple syrup produced at Pack Forest.Kiyomi Taguchi / University of Washington

As for the flavor? The Pack Forest’s batches of syrup taste different from the maple syrup you’d probably buy in a store — more earthy with hints of vanilla and minerals. Ganguly suggests local chefs and foodies might be especially interested in this locally sourced, unique product.

So far, the Pack Forest site is only producing small amounts of maple syrup, and the winter of 2020-2021 was too warm to collect very much sap at most of the sites. But Ganguly is confident that there’s potential to scale up production with more sites, and for a maple syrup industry to take root in Washington. 

“Hopefully, after this project, people will start viewing bigleaf maple trees in a different light, and assign more value to them,” he said.

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