As Maple Weekend 2018 welcomes visitors to maple farms across the state March 24 and 25, Cornell experts are assessing how fluctuating temperatures have impacted production this year.

For sap to flow well, temperatures ideally need to dip below freezing at night and rise above it during the day. Despite 2018 having the fifth warmest February in New York’s recorded history with an average of 29.6 degrees, March has been unseasonably cool, which has stalled the state’s maple syrup production.

“We are having a ‘when-is-it-going-to-happen’ type of year,” said Stephen Childs, New York state maple specialist in the Department of Natural Resources.

Childs is part of the Cornell Sugar Maple Program, which conducts research and outreach (including workshops and instructional videos) on maple production, and maintains maple sugar production at Cornell’s Arnot Research and Teaching Forest near Ithaca and at the Uihlein Maple Teaching and Research Forest in Lake Placid, New York.

This February, Childs and his colleagues collected about half their usual crop at Arnot Forest and about 20 percent of the crop at Uihlein. Almost all of that production occurred in February when temperatures rose above freezing, with very little production so far this month.

With regard to timing, a few operations start tapping during freeze-thaw periods in the late fall, and a few operations wait until March, but the vast majority start tapping sometime in January and February, Childs said.

“I’ve been involved with maple for over 50 years and the start date has gradually moved earlier, but out of the last four years, three have been quite late,” he said.

Research in 2010 by Brian Chabot, professor emeritus in the Department of Ecology and Evolutionary Biology, reported that as the climate warms, the freeze-thaw cycles for tapping trees could move earlier by as much as a month in the Northeast by 2100 and maple syrup production could decline slightly.

Though declines are predicted in the future, the market for maple syrup in New York has more than doubled since 2012, according to the USDA. New York now has the second-highest output of maple syrup in the United States and set a 73-year record with 760,000 gallons of syrup produced in 2017, with 2.65 million maple tree taps.

“We have more than twice as many taps as we did in 2004 when I started working at Cornell, and we produce nearly three times as much per tap. That’s due to technology improvements,” Childs said.

One of those improvements is a vacuum pressure tubing system that sucks sap out of trees, as opposed to the conventional drip method from a tap into a bucket. The other big shift has been the use of reverse osmosis, which involves a highly energy-efficient pump and a membrane that filters out water from the sap. As part of its outreach efforts, the Cornell Maple Program has made a series of videos explaining these technologies and how they are used. Collectively, these videos have been viewed well over 100,000 times.

Since January of 2017, Childs and colleagues at the Cornell Sugar Maple Program have made up to 100 presentations across the state, with more than 3,400 participants. Topics have included various aspects of sap production and technology and how to make different kinds of maple products, such as maple cream and maple candy.