The role of Douglas-fir stem sapwood andheartwood in the mechanical and physiological support of crowns and development of stem form
Document Type
Article
Journal/Book Title/Conference
Can. J. For. Res.
Volume
11
Publication Date
1-1-1981
First Page
459
Last Page
464
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.
Recommended Citation
Long, J.N., F.W. Smith and D.R.M. Scott. 1981. The role of Douglas-fir stem sapwood and heartwood in the mechanical and physiological support of crowns and development of stem form. Can. J. For. Res. 11:459-464.
