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Article
The role of Douglas-fir stem sapwood and heartwood in the mechanical and physiological support of crowns and development of stem form
Canadian Journal of Forest Research (1981)
  • James N. Long, Utah State University
  • Frederick W Smith
  • David RM Scott
Abstract
The mechanical and physiological support of a tree's crown is the principal function of its bole. A simple model for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) of different crown classes explains much of the observed differences in stem form development. Sapwood cross-sectional area at any height on the bole of the tree was found to be related linearly to the amount of foliage above that point; however, in large trees the sapwood area needed to supply transpiring foliage with water is insufficient to provide mechanical support. The combination of sapwood and heartwood was found to provide the stem form that would be expected to ensure uniform resistance to bending by the wind.
Disciplines
Publication Date
1981
DOI
10.1139/x81-063
Citation Information
James N. Long, Frederick W Smith and David RM Scott. "The role of Douglas-fir stem sapwood and heartwood in the mechanical and physiological support of crowns and development of stem form" Canadian Journal of Forest Research Vol. 11 Iss. 3 (1981) p. 459 - 464
Available at: http://works.bepress.com/jameslong/184/