Effects of Artificial Defoliation of Pine on Subsequent Shoot and Needle Growth
Abstract:Needles of Pinus resinosa Ait. trees in a 5-year-old plantation were severed at distal ends of fascicle sheaths to simulate insect defoliation. In July 1959, needles of 1959, 1958, 1957, 1959 + 1958, 1959 + 1957, and 1958 + 1957 origin were removed. Needle and shoot elongation were measured in the fall of 1962. In 1960 there was a reduction in shoot elongation of 10 to 40 percent in 3 of the treatments. In 1961, removal of 1959 needles reduced shoot elongation by 38 to 63 percent. Removal of 1959 needles reduced by 19 to 32 percent the length of needles in 1960 and increased length by 9 to 42 percent in 1961. Discussed are: the effects of defoliation on availability of needles as storage organs and producers of photosynthate; and needle length changes relative to the availability of photosynthate at the time of needle primordia formation and needle elongation. Pinus sylvestris L. was used in similar, but smaller scale tests.
Document Type: Journal Article
Affiliations: Assistant Professor, Departments of Forestry and Wildlife, and Entomology, Virginia Polytechnic Institute, Blacksburg
Publication date: March 1, 1965
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