Crown shyness in lodgepole pine stands of varying stand height, density, and site index in the upper foothills of Alberta

• Published in: Canadian journal of forest research Vol. 36; no. 9; pp. 2104 - 2111
• Main Authors: Fish, H, Lieffers, V.J, Silins, U, Hall, R.J
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.09.2006; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Alberta; Biological and medical sciences; Canopies; canopy closure; canopy gaps; coniferous forests; conifers; Environmental aspects; equations; Evergreen trees; forest inventory; forest litter; forest stands; forest trees; Forestry; Fundamental and applied biological sciences. Psychology; height; leaves; Light transmission; Lodgepole pine; overstory; Physiological aspects; Pine trees; Pinus contorta; plant competition; site index; spatial distribution; stand characteristics; stand density; tree and stand measurements; tree crown; Treefall; Alberta; Canada, Alberta; Forestry
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x06-107

Crown shyness is the empty space between crowns in fully stocked stands that is not related to treefall gaps. The objectives of this study were to determine the stand and site factors that control crown shyness in lodgepole pine (Pinus contorta Dougl. ex Loud.) stands and to evaluate whether stands experiencing crown shyness compensate for leaf area losses by maintaining longer crowns. We measured canopy closure (i.e., the inverse of crown shyness), crown radius and length, and green litterfall in stands of various height, relative density, and site index. Canopy closure decreased with stand height and increased with site index and relative density. Green litterfall increased with height and relative density. Crown radius and crown length reached a plateau by 810 m height, despite increased spacing between tree boles with increasing stand height. Crown radius increased with height and site index but declined with relative density and slenderness coefficient. Crown length also increased with height and site index but declined with slenderness coefficient. Despite the fact that, in tall stands, where >50% of the sky was not covered by crowns, there was not an accompanying increase in crown length to take advantage of the apparent increase in light transmission to the lower crown.