Assessing Clearcutting Activities: Compiling harvest opening sizes

Introduction

How does one compile the harvest opening size distribution to gauge the effects of clearcutting?

As forest development activities increase worldwide, public reactions are frequently negative. Forest harvesting activities, in particular, draw considerable attention. Forest managers are often confronted about clearcut harvesting and its perceived negative effects.

Because clearcuts are so common and obvious, their size, which can be upward of 100 ha, can cause an immediate negative public reaction. From an aesthetic perspective, of course, small is beautiful. However, from an economic perspective, small probably isn't beautiful, as it's much more costly to operate across several small clearcuts as opposed to one large one. Likewise, from an ecological perspective, small is not necessarily good. It spells fragmentation of conditions and is not desirable; rather, a mixture of sizes from small to large is important for the ecological well-being of a forest.

A numeric distribution of harvest opening sizes then would be one way of measuring and assessing clearcutting in a forest from all three perspectives—aesthetic, economic, and ecological. It would tell us if the openings created by recent clearcuts are mostly large, mostly small, evenly distributed, or some other distribution.

Location

A small 1400 ha woodlot in the Acadian-New England forest region of North America

Time to complete the lab

3 hours

Prerequisites

Students should have a basic working knowledge of GIS data, including use of a geodatabase. Familiarity with basic forest analysis techniques is important, while familiarity with forest inventory data and terminology is also helpful, but not essential.

Data used in this lab

Feature classes and rasters for a forest woodlot (personal geodatabase)

Geographic coordinate system: NAD 1983 CSRS New Brunswick Stereographic

Datum: NAD83

Projection: New Brunswick Double Stereographic Grid (unless otherwise stated)