The Relationship of Lodgepole Pine Cone Age and Seed Extractability
All closed cones were collected from the crowns of eight lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) trees and separated by age and tree. The times in a kiln at 180°C required to melt the resin bonds holding the scales closed were recorded. Seed extraction was done at 60°C. Seed yield was determined by periodic shaking of the cones. The effect of cone moisture content upon rates of seed release was studied using three levels of cone moisture content and three bulk seed lots. This study shows that cone age is not very important (r² = 0.25) in influencing times to break resin bonds but that initial cone moisture content is (r² = 0.80). Moist cones (15 percent) break their resin bonds much more slowly than do drier cones (6 to l0 percent moisture). Cone moisture content did not vary by cone age. Since over 80 percent of the studied cones were less than 16 years old and showed little if any effect of age upon the percent of seed released, cone age was considered unimportant for limiting cone collection to cones of a specific age class. The portion of empty seed increased dramatically over the extraction period reaching 45 percent of sample after 10 hours. Forest Sci. 27:62-70.
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Keywords: Pinus contorta
Document Type: Journal Article
Affiliations: Department of Forest Science, The University of Alberta, Edmonton, Alberta, Canada T6G 2G6
Publication date: 01 March 1981