Abstract
Understanding how soil and foliar nutrients play a role in sap sweetness of sugar maples is economically important for producing maple syrup. Sugar concentration affects the amount of sap required to produce a gallon of syrup. Sugar maples were sampled for sap sweetness in five stands in the White Mountains of New Hampshire and correlated to foliar and soil nutrients. Treatment plots were fertilized with N, P, N and P, and Ca to test whether a nutrient addition increases sap sweetness. Higher sugar concentration in the sap was correlated with soil nitrogen mineralization. Foliar P had a negative correlation with sap sweetness while trees with higher foliar N:P had sweeter sap. Addition of 30 kg N ha/yr increased sap sweetness two years after initial treatment. By selecting sites with higher soil nitrogen or fertilizing with N, maple producers may be able to collect sweeter maple sap.