The ecological roles of logs in Australian forests and the potential impacts of harvesting intensification on log-using biota

Abstract

A review is presented of the ecological values of logs in Australian eucalypt forests. Logs are a key component of stand structural complexity and have critical functional roles for forest biodiversity including:- (1) providing nesting and sheltering sites for biota, (2) providing foraging substrates for predators like snakes and predatory invertebrates such as velvet worms, (3) providing basking and hibernation sites for reptiles, (4) facilitating animal movement, (5) providing places for key social behaviours, (6) acting as plant germination sites, (7) providing substrates to promote the growth of fungi, (8) providing mesic refugia for organisms during drought and/or fire, and (9) contributing to heterogeneity in the litter layer and patterns of ground cover. Logs also play significant roles in nutrient cycling in forests. The role of logs is often ignored in forestry operations, including those where harvesting intensification will occur through the removal of dead and/or "defective" standing trees and logs under the guise of removing so-called waste or logging "residues". Recently proposed intensive large-scale forestry operations in the Australian native forest estate (e.g., biomass burning power plants and charcoal plants) have the potential to reduce stand structural complexity, alter forest ecosystem function and negatively impact upon log-dependent species in those part of the landscape where harvesting takes place. The risks of such impacts have not been adequately measured in Australia, but they need to be addressed urgently. Prescriptions for the retention and future recruitment of logs must be developed to avert possible losses of biodiversity.