Effects of Repeated Defoliation on Root and Root Collar Extractives of Sugar Maple Trees
Abstract:Extractive levels of cell content materials from the roots of sugar maple trees defoliated in June and harvested in July, August, or November were lower than levels from roots of undefoliated controls. Results were similar for trees defoliated in July. Extractive levels in trees defoliated in August were not lower 3 weeks after defoliation than levels in control trees but were lower 10 weeks after defoliation. Although extractive levels in trees defoliated in July of 2 or 3 successive years were not significantly lower, levels did tend to decrease with number of defoliations. The extractive level was much higher in root bark than in root wood, but after defoliation the greatest decline in extractive levels was in root wood. Defoliation had no apparent effect on extractive levels in root collar bark, but levels were lower in root collar wood of twice-defoliated (June and August) trees harvested in November than in controls. The amount of glucose and fructose markedly increased in roots of defoliated trees, and the amount of starch declined. Forest Sci. 17:91-95.
Document Type: Journal Article
Affiliations: Plant Pathologist, Forest Insect and Disease Lab., Northeastern Forest Exp. Sta., USDA Forest Service, Hamden, Conn.
Publication date: March 1, 1971
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