The effects of site characteristics on the landscape-level windthrow regime in the North Shore region of Quebec, Canada

Understanding windthrow is essential for the implementation of ecosystem management, especially in forests with long fire return intervals. Our study describes windthrow dynamics at a landscape scale of the Quebec North Shore region, Canada, and evaluates the effect of some site (soil surface material thickness or deposit thickness, drainage, slope, topography and wind), and stand (dominant species, height and density) characteristics on windthrow probabilities. The SIFORT database, created by the Ministry of Natural Resources and Wildlife of Quebec, the Quebec forest fire control agency and the Quebec forest pest and disease control agency, was used to perform a spatiotemporal analysis of windthrow, according to site and stand characteristics. Windthrow probabilities were influenced by topographic exposure (topex), slope classes and deposit thickness. Windthrow probabilities increased with topographic exposure. Windthrow occurrence was highest when deposit was thick (more than 1m) and slope class was medium (from 15 to 30 per cent). Finally, this study has shown the importance of partial windthrow at the landscape scale in the North Shore region. Thus our results suggest that from an ecosystem management perspective, clear-cutting must be partly replaced by partial cuts, in order to emulate the regional dynamics of partial windthrow.