Finding the sweet spot: Shifting optimal climate for maple syrup production in North America

TitleFinding the sweet spot: Shifting optimal climate for maple syrup production in North America
Publication TypeJournal Article
Year of Publication2019
AuthorsRapp, Joshua M., Lutz David A., Huish Ryan D., Dufour Boris, Ahmed Selena, Morelli Toni Lyn, and Stinson Kristina A.
JournalForest Ecology and Management
Volume448
Pagination187 - 197
Date PublishedJan-09-2019
ISSN03781127
KeywordsAcer saccharum, climate change, Maple syrup, Predictive model, Yield
Abstract

Climate change is affecting the benefits society derives from forests. One such forest ecosystem service is maple syrup, which is primarily derived from Acer saccharum(sugar maple), currently an abundant and widespread tree species in eastern North America. Two climate sensitive components of sap affect syrup production: sugar content and sap flow. The sugar in maple sap derives from carbohydrate stores influenced by prior year growing season conditions. Sap flow is tied to freeze/thaw cycles during early spring. Predicting climate effects on syrup production thus requires integrating observations across scales and biological processes. We observed sap at 6 sugar maple stands spanning sugar maple’s latitudinal range over 2–6 years to predict the role of climate variation on sugar content and sap flow. We found that the timing of sap collection advanced by 4.3 days for every 1 °C increase in March mean temperature, sap volume peaked at a January-May mean temperature of 1 °C, and sap sugar content declined by 0.1 °Brix for every 1 °C increase in previous May-October mean temperature. Using these empirical relationships, we projected that the sap collection season midpoint will be 1 month earlier and sap sugar content will decline by 0.7 °Brix across sugar maple’s range by the year 2100 in an RCP 8.5 climate change scenario. The region of maximum sap flow is expected to shift northward by 400 km, from near the 43rd parallel to the 48th parallel by 2100. Our findings suggest climate change will have profound effects on syrup yield across most of sugar maple’s range; drastic shifts in the timing of the tapping season accompanied by flat to moderate increases in syrup yield per tap in Canada contrast with declines in syrup yield and higher frequencies of poor syrup production years across most of the U.S. range.

URLhttps://linkinghub.elsevier.com/retrieve/pii/S0378112719303019
DOI10.1016/j.foreco.2019.05.045
Short TitleForest Ecology and Management