In 2015, maple syrup production in the U.S. reached $125 million. This industry supports large maple corporations as well as enthusiasts who sell at farmers markets. Because the tapping season is dependent on weather conditions, maple syrup production is particularly vulnerable to changes in climate. Warming temperatures, changes in precipitation, and changes in freeze and thaw cycles will impact maple trees and syrup production.
WHAT: The Northeast CSC supported the development of ACERnet, an international network of scientists and managers dedicated to studying the maple tree’s ecology and management, with a focus on the relationship between sap quality and climate. ACERnet has six study sites covering the range of sugar maples, from Virginia to Quebec.
FINDINGS:ACERnet scientists identified how changes in weather conditions impact sugar maple trees and sap production. These impacts include fewer trees, reduced tree health and growth, shortened tapping seasons, and decreased sap quality and quantity. These changes could lead to reduced rates of syrup production in the U.S., with some areas in the southern half of sugar maple’s range becoming unsuitable for production. Maple producers are already reporting earlier and more variable tapping seasons.
However, the industry is adapting to these changes. Improving sap collection technology has increased the efficiency of production and has made lower sugar content sap more profitable. These improvements have so far offset most of the negative impacts of variable seasons. Alleviating other environmental stressors, such as acid rain and insect pests, can prolong tree health and improve sap quality. The industry can also improve resilience by diversifying the species of trees tapped, which increases the number of available trees and lengthens the tapping season. Other maples, birches, and even walnuts can be tapped for sweet sap.
SIGNIFICANCE: Maple trees provide almost year-round economic activity for maple tree dense states, through maple sap products and tourism of fall foliage. Maple syrup is also a traditional food source for a number of tribes in the region, such as the Menominee Tribe. The information obtained from the network will help the maple industry adapt to and continue to thrive under future conditions. ACERnet products can help improve the resilience of the industry by providing maple producers with resources, such as projections of future tapping conditions, to make decisions on how to best maintain or grow syrup production in the face of changing climate conditions.