Abstract:
 

Managing maple tree stands for the production of maple syrup requires consistent monitoring of the quality and production of the trees within the stand.  To establish a mature maple stand that is productive, young trees that have a high sugar content are kept and given space to grow by cutting less productive trees.  To improve a young maple tree stand, the sugar content of the sap is measured to identify the higher quality trees and the trees to thin.  Thinning the lower quality trees allows maple trees with higher sugar content in the sap room to grow and necessary space required for the tree’s crown so that it is not competing for sunlight and nutrients.  Trees with a sugar content of 3.5% are considered normal and trees ranging from 5% to 7% have higher sugar content.  The trees were ranked into three categories of sugar content: A (6.0% to 7%), B (4.5% to 6.0%) and C (3% to 4.5%).  Sampling must be done by collecting a small amount of sap from the tree on one of the first sap runs of the spring.  The sap is then allowed to warm to room temperature and sugar content is measured (% BrIX) using a refractometer.  This research was conducted at the Cornell Cooperative Extension Farm on Route 68.  A young stand on the farm property (trees less than 10 cm at diameter at breast height) was assessed to determine which trees to cut and which to keep.  The stand was approximately an acre in size and contained approximately 300 saplings.  All trees were sampled in Spring 2000, and trees with the higher sugar content were resampled in Spring 2001.  Retesting the trees with the higher sugar content in Spring 2001 was a way of assessing their variability between years and the degree to which they lose their sugar content with age.  The trees with the highest sugar content last year measured lower this spring and were not the highest ranked trees in 2001.  A high level of variability was detected, therefore several years data may be necessary to fully determine the trees, which may be beneficial to keep, and the trees worth thinning.