A diagnostic framework for windthrow risk estimation

Windthrow impacts are negative if stand or forest level management objectives are compromised. Consideration of the impact of expected damage on management objectives enables mitigative actions to be prescribed where necessary. The level of damage along recent cutblock boundaries from endemic peak winds depends on biophysical and management factors. A diagnostic framework is presented in which windthrow patterns in harvested areas are observed, and site indicators and management regimes are compared with areas proposed for harvesting. Topographic exposure, soils and stand components of biophysical hazard are separately assessed and then integrated. The orientation and placement of the proposed boundaries relative to damaging wind directions is considered and integrated with biophysical hazard to yield an estimate of expected damage. Practitioners are guided through the assessment process by a series of simple diagnostic questions. Key words: windthrow, blowdown, wind damage, hazard assessment, risk assessment