Summary
Published in Canadian Journal of Forest Research 33: 2452-2459
Precommercial thinning is often used to control stand density in naturally regenerated balsam fir (Abies balsamea (L.) Mill.) stands. Early stand density control could have beneficial effects on longer term stand stability through a modification of stem shape and root development. To assess the effect of precommercial thinning, two thinned and two unthinned stands were selected. Root sections were collected at 25 cm from the centre of the stem for all major roots (diameter greater than 2 cm). A disk was also cut at breast height level. From these disks, response in radial growth was determined. Detailed root measurements were taken on the sample disks to assess treatment effect on the following variables: asymmetry in root cross-sectional area (CSA) distribution, individual root shape, as well as changes in root shape over time. A quick and pronounced response in root growth occurred. This response was greater than that observed in the trunk. No asymmetry in root CSA distribution was observed at the stand level. Trees allocated more to radial growth above the biological centre of the root both in treated and control stands, but this trend was increased by thinning. Roots also tended to develop T-beam shapes over time, both in control and thinned stands. Most roots initially did not possess an I-beam shape and did not develop one during the course of the study. According to our results, trees respond quickly to the new growing conditions created by thinning by increasing biomass allocation to parts of the roots where mechanical stresses are greater.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests, Silviculture
Departmental author(s):
Author(s)
RUEL, Jean-Claude, Catherine LAROUCHE et Alexis ACHIM
Year of publication :
2003
How to get the publication :
PDF available upon request
Keywords :
morphologie racinaire, éclaircie précommerciale, accroissement, forme de poutre en T, sapin baumier, Abies balsamea, sylviculture des forêts naturelles résineuses, silviculture and yield of natural forests - softwood stands, sylviculture et rendement des forêts naturelles - peuplements résineux, root morphology, precommercial thinning, growth, T-beam shape, balsam fir
