THE WINDTHROW TRIANGLE - A RELATIVE WINDTHROW HAZARD ASSESSMENT PROCEDURE FOR FOREST MANAGERS

Wind is a major cause of damage in North American forests. Salvaging w indthrow is costly and may disrupt silvicultural and management plans. Non-salvaged windthrown trees provide bark beetle habitat, increase f uel loading, and limit the mobility of wildlife and recreationists. Fr eshly exposed stand edges and recently partially cut stands are partic ularly prone to wind damage. Windthrow results from complex interactio ns of many environmental factors, which can be grouped into three broa d components of hazard: topographic exposure, soil properties, and sta nd characteristics. These three component groups form the three sides of the Windthrow Triangle. This simple model can be used to evaluate t he relative windthrow hazard of forested sites. The evaluation will as sist managers with the formulation of treatment prescriptions designed to reduce losses from endemic windthrow. The model incorporates stand level attributes and is not intended to replace existing methods for individual hazard tree assessment.