Summary
Published in Tree Physiology 6: 371-380
ln the autumn of 1987, young balsam fir (Abies balsamea (L.) Mill.) and white birch (Betula papyrifera Marsh.) trees were thinned and their water relations followed during the next two growing seasons. At the beginning of the first summer following treatment, thinned trees of both species had lower osmotic potentials at full saturation (Yp,sat) and at turgor loss point (Yp,tlp) compared with controls. At this time, Yp,sat was linearly related to the percentage of full sunlight reaching the trees. A higher sugar concentration in leaves was an important component of the lower Yp,sat of thinned trees. For the other two sampling dates during the first growing season after treatment and all three sampling dates during the second growing season after treatment, little osmotic adjustment of the thinned trees relative to the control trees was observed in either species. The absence of osmotic adjustment during the second growing season following thinning suggests that other mechanisms were responsible for the acclimation of the treated trees to the higher atmospheric evaporative demand. Sapwood permeability (k) of white birch was higher than that of balsam fir, but no differences in k or in sapwood area were found between treated and control trees of either species. Predawn water potentials (Ypred) of treated trees were less negative than those of controls.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests
Author(s)
POTHIER, David and Hank A. MARGOLIS
Year of publication :
1990
Format :
Paper
How to get the publication :
Keywords :
Abies balsamea, Betula papyrifera, balsam fir, white birch, silvicultural regime, thinning, Montmorency Forest, osmotic potential, sapwood permeability, photosynthetically active radiation, PAR, sugar analysis, statistical analysis, tugor loss point, sugar concentration
