Sap-Sugar Content of Forest Service Grafted Sugar Maple Trees
In March and April 1983, 289 and 196 young grafted sugar maple trees were tapped and evaluated for sap-sugar content. In April, sap was collected from taps both above and below the graft union. Diameter of all tapped trees at 18 inches above the ground was measured. Analysis of the data revealed that: (1) trees selected for high sugar yield cannot be reproduced by grafting on rootstock of unknown but varying sugar content without encountering large fluctuations in sap sweetness of the trees produced; (2) diameter is not correlated with sap sweetness of young grafted trees; (3) numerous sap-sugar readings over time may be necessary to identify the sap sugar characteristics of a candidate sweet tree; and (4) the cause of the variation in sap-sugar content of trees over time needs to be investigated more fully.