Why does sweetness vary from year to year?
Sap sweetness has been observed to be lower in years following a growing season when conditions were unfavorable for production of sugar through photosynthesis. For example, if a stand is attacked one year by insects that defoliate the maple trees, the next year s sap would be expected to be low in sugar. Some scientists have speculated that a vigorously growing tree might use up so much of the sugar produced by the leaves that it would have a lower sugar content the following year.
