Summary:
Published in Canadian Journal of Forest Research 19: 432-439
The saturated sapwood permeability (k) of jack pine (Pinus banksiana Lamb.) from stands of different ages and site qualities was measured using a constant water flow apparatus. Saturated sapwood permeability at the base of the live crown (BLC) increased with age and reached a plateau just beyond 4 x 10-12 m2. The rate at which this plateau was reached, however, was dependent on site quality. Such age-related increases in k can partially explain how trees can maintain similar daytime leaf water potentials at different stages of stand development. Within age-classes 15 and 35, k at BLC was greater on the better-quality sites and was strongly correlated with both diameter and height growth. For age-class 120, k at BLC was not significantly different among sites. Saturated sapwood permeability at BLC could be predicted from age and site quality, using a negative exponential function (R2 = 0.66). The ability to predict changes in k with stand development has potential for improving leaf area estimates derived from sapwood area - leaf area correlations. Sapwood conductance from ground level to the upper third of the crown decreased with age for good-quality sites and increased with age for poor-quality sites. It corresponded to the pattern of average annual height growth over the last 5 years (R2 = 0.61). The number of annual rings contributing to the sapwood at a given age was independent of site quality. This suggests that the historical reconstruction of a tree's leaf area and growth efficiency is possible even after the formation of significant amounts of heartwood.
Sector(s):
Forests
Catégorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests, Silviculture
Author(s):
POTHIER, David, Hank A. MARGOLIS and Richard H. WARING
Year of publication:
1989
Format:
Paper
How to get the publication:
Keyword(s):
conifer, Pinus banksiana, jack pine, sapwood, live crown, BLC, base of the live crown, sapwood permeability, sapwood conductance, water potential, sylviculture des forêts naturelles résineuses, silviculture and yield of natural forests - softwood stands, sylviculture et rendement des forêts naturelles - peuplements résineux