Amelioration of adverse snig-track soil properties and revegetation as influenced by forest-site characteristics and time since harvesting

Compaction and soil displacement during harvesting were studied on eight harvested areas of various ages covering three forest sites. Under a dry eucalypt forest site, compaction of the most severely disturbed (primary) snig tracks persisted 12 years after harvesting. Increased soil strength also persisted. Regeneration of Eucalyptus sieberi was as good on primary snig tracks as on undisturbed areas, despite topsoil displacement. Under two wet forest sites with very high rainfall there was generally amelioration of compaction within one year of harvesting, when comparing equivalent soil horizons. However, displacement of surface soil from primary snig tracks on wet forest sites resulted in poor conditions for regeneration, and trees generally failed to survive or at best remained stunted. The exposed subsoil had attained little of the characteristics of undisturbed topsoil, and soil strength generally persisted at elevated levels. Understorey species tolerant of poorly aerated soil were the most prominent early colonisers on primary snig tracks on all sites, while other species dominated undisturbed areas. Introduction