QUANTIFYING EDGE EFFECT AND PATCH SIZE FOR MULTIPLE-USE SILVICULTURE - A DISCUSSION PAPER

An argument is presented that the essential difference between even-aged and uneven-aged silviculture lies in the proportion of the patch that is influenced by edge effect. These edge effects may extend well beyond the normally accepted boundary between even-aged and uneven-aged stands. Examples are presented to show that there is not one static edge effect but many dynamic edge effects and that the differences between even-aged and uneven-aged stands are represented by a continuum rather than there being a distinct division between them. In the continuing debate on appropriate forest management practices, the differences between even-aged and uneven-aged silviculture have been oversimplified and are often represented in their extremes. In this paper it is argued that research to quantify the magnitude and the extent of these edge effects is necessary to provide the essential data to design patch sizes to meet specific multiple-use management objectives. The integration of these data would provide the basis for objective trade-offs between various forest values and for the objective evaluation of the long-term impact of different silvicultural practices.