Sugar Maple Research Findings

What has already been learned about climate change impacts on maple trees and syrup?
(Information from an interview with Dr. Rapp on WDSO Radio, January 2016)

Has climate change had any effect on the distribution of sugar maple?

Tree species' distributions are determined in part by climate. As the climate warms, we expect trees' distributions to move north. However, this process takes time since trees are long lived and they can’t just pick up and move. So far, sugar maple seems to be maintaining its abundance throughout its range, even at the southern range edge. For the next several decades at least, we expect there to be trees in the places we’ve come to expect them. In the long-run however, sugar maples are very likely to move north.

How is our changing climate affecting tree health?

This is a hard question to answer, because the effects of climate on tree health probably depend on where you are. For example, in the Adirondacks in New York State, trees have been growing slower in recent decades, and this may be related to changes in climate. In the Midwest though, trees tend to grow faster at warmer sites. In general, climate conditions are expected to become more stressful, and that may make trees more susceptible to other threats, like invasive species or pollution.

How does climate change impact the length and timing of the tapping season?

The tapping season depends on the weather. For the sap to flow we need nights that are below freezing followed by warm days. The time in the year when these conditions exist is getting earlier, meaning that maple tappers need to tap earlier to collect sap. There are also some modeling studies that suggest that the tapping season will get shorter as climate warms.

What does climate have to do with sap quality?

Sap quality is determined by the sugar content of the sap and its secondary chemistry. There is some evidence that sap sugar content has been decreasing and some think this could be related to climate, but there have been no really good studies. Even less is known about how sap chemistry is related to climate. This is why Dr. Rapp’s project focuses on sap quality.

Additional information

Last updated: December 29, 2016