Management of compaction during harvest of Pinus plantations in Queensland: I. Policy considerations for controlling machine activity

Abstract

The approach used to control compaction damage during forest harvesting in Pinus plantations established on coarse-textured soil types in Queensland is to allow year-round harvesting/extraction operations, and prescribe compaction mitigation measures that, inter alia, prohibit machine operations when compaction risks are determined to be excessive.

In this paper, alternative approaches to controlling harvesting-induced compaction are examined. This is followed by a discussion of two techniques for determining when compaction risk is excessive for ground-based harvesting: (i) predictive models; and (ii) reactive approaches. With the first, predicted compaction damage is compared to a criterion of ‘acceptable’ compaction in order to determine when machinery operations should be suspended and/or to schedule harvesting in compartments where compaction damage is not expected. The ‘reactive’ approach is based upon allowing harvesting/extraction operations to occur until an ‘unacceptable’ compaction condition results, at which time further operations are prohibited until soil strength increases.

Because of pressure for rapid development of guidelines in the early 1990s, the ‘reactive’ approach has been used in Queensland. Rut depth and shearing were selected as easily and reliably measured indices of compaction damage. In addition to describing these developments, the notion of ‘acceptable’ compaction is discussed, and justification given for the ‘level of acceptable compaction’ incorporated into the guidelines.