Soil disturbance and post-logging forest recovery on bulldozer paths in Sabah, Malaysia.

摘要

The extent of soil disturbance associated with bulldozer yarding and the regrowth of woody vegetation on bulldozer paths (skid trails) was examined in selectively logged dipterocarp forest in Sabah. In an area logged in 1993, using conventional (i.e. uncontrolled) harvesting methods, about 17% of the area was covered by roads and skid trails. In contrast, in a 450-ha experimental area where reduced-impact logging guidelines were implemented, 6% of the area was similarly disturbed. Skid trails in the reduced-impact logging areas were less severely disturbed than those in conventional logging areas; the proportion of skid trails with subsoil disturbance was less than half that in conventional logging areas. Four years after logging, woody plant recovery on skid trails was greater in areas logged by reduced-impact than by conventional methods. Skid trails where topsoil had been bladed off had less woody vegetation than skid trails with intact topsoil. In a chronosequence of logging areas (3, 6, and18 years after logging), species richness and stem densities of woody plants (>1 m tall, <5 cm dbh - diameter at breast height) were lower on skid trail tracks than on skid trail edges or in adjacent forest. Both richness and density increased with timesince logging, but even 18 years after logging, abandoned skid trails were impoverished in small woody stems compared with adjacent forest. The study shows that minimizing soil and stand disturbance during logging appears to allow a more rapid recovery of vegetation on bulldozed soils, but the long-term fate of trees growing on compacted soils remains uncertain.