Does Masting Really Lead to Lower Sap Sugar Concentrations?

M aple producers often wonder about how the weather and various stresses affect the health and productivity of maple trees. In a recent issue of the Maple Digest, (February 2015) an article by Joshua Rapp showed a link between masting (heavy seed production) in the fall of one year and significantly reduced maple syrup production in the following spring season. Rapp describes research previously published in the journal Forest Ecology & Management with his co-author Elizabeth Crone. In both papers , they hypothesize that since sugar maples rely on stored nonstructural carbohydrates (NSC) to produce seed during a masting year, there would be less NSC available in sap the following year. Thus, in sugaring seasons following a seed year, the sap sugar concentration (SSC) from trees would be lower than normal, and thus syrup production should be correspondingly lower in that year. While this is an interesting theory that certainly has some merit for further investigation, the methods by which the theory was tested have seri-Maple Digest 54(2): 14-19.