A GIS based approach to map wind exposure for windthrow hazard rating

Abstract

Wind exposure is one of the most important factors influencing the incidence of windthrow. A proper windthrow hazard management approach should include a method for assessing wind exposure as influenced by topography. This article discusses the design of a routine that enables the user to automatically map wind exposure over a landscape. The routine is written for ArcView and is based on the distance-limited topex developed by the British Forestry Commission. It can calculate wind exposure over management units based on digital terrain models. Validation with a wind tunnel study has shown that it provides realistic estimates of wind exposure that can be used at the forest management level.