Modelisation du risque de chablis en foret boreale pour l'epinette noire et le pin gris (French and English text).

摘要

Windthrow is a natural disturbance that is likely to become more important with the refinement of silvicultural practices in forest management. Indeed, the increasing use of partial cutting and the reduction of the size of cutting blocks have been associated to greater risk of damages. To help in predicting windthrow hazard, the present study has been designed to compare the mechanical resistance of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.). Among the five selected sites, two were located in pure black spruce stands and the remaining three, in stands composed of a mixture of black spruce and jack pine. Soils with restrictive conditions to root development were also included in the analyses. To measure the mechanical resistance, each tree was pulled over using a cable and winch system. The maximal applied forces that a tree can withstand before failure is expressed as the critical turning moment ( Mc). (Abstract shortened by UMI.)