Research for Ecologically Sustainable Forest Management in Victorian eucalypt forests

Abstract

This paper describes some of the research needed to help forest managers achieve Ecologically Sustainable Forest Management. As a case study, it also presents an overview of some of the research conducted to meet those needs in the state of Victoria, and identifies priorities for further research, monitoring and adaptive management. Vertebrate wildlife (mainly birds and mammals) has been a major focus of this review. The main strategic research questions concern the successional effects of logging, the relative merits and costs of integration or segregation and the appropriate scale for spatial integration. Retrospective research is a valuable tool to address some of the key questions, but longitudinal studies (i.e. over time), are also needed. Successional studies have identified hollow-dependent wildlife species and species that feed from open ground among trees as those that are most sensitive to logging. Thinning and control burning may have potential value as tools to modify regrowth forest structure to benefit the latter group, but this new concept needs field-testing. A general focus on hollow-dependent species may have diverted attention from the needs of other groups. A logical scheme is presented for evaluating costs and benefits of spatial integration or segregation in particular cases. The shape of the response curve is crucial in making these evaluations, but this aspect has received little attention. Segregation often has benefits both for wildlife conservation and wood production, but there are exceptions and socioeconomic reasons for developing more integrated systems. Retaining patches of habitat on selected coupes combines some of the benefits of both approaches, and has been introduced on a trial basis in mixed eucalypt forests and ash forests, with associated monitoring. Effects of spatial scale and pattern have been studied in ash forests but more work of this sort is needed in mixed eucalypt forests and box-ironbark forests. Large owls have been used as umbrella species to select areas for special protection based on extensive field surveys, modelling and field-testing. Further monitoring and detailed research is needed to evaluate and refine the effectiveness of this strategy. This approach forms part of a suite of forest planning processes, which increasingly involve community participation. Associated research is needed to help inform debate and decisions in an adaptive management framework.

Designing old forest for the future: Old trees as habitat for birds in forests of Mountain Ash Eucalyptus regnans

“…Subsequent studies in BoxIronbark forests have shown that more large old trees were flowering at a given time than young trees (Wilson and Bennett, 1999). Previous studies have shown that honeyeaters tend to be more common in old than young forest (Loyn, 1985c(Loyn, , 2004. Provision of cavities has been a focus of several studies in Australia (e.g.…”

“…Forest managers accept the need to maintain old trees at suitable distributions in the landscape, but need information to guide them in making strategic decisions at the scale of individual stands and the broader forest landscape (Loyn, 1985a(Loyn, , 2004Gibbons et al, 2002;Lindenmayer and Franklin, 2002). The issue is a challenge because wood production is greatest at the younger stages of stand development, and deliberate retention of old trees on coupes and old stands in the landscape (and younger trees and stands to replace them over time) are likely to be needed (Loyn, 1985a).…”

“…Current planning processes address some of these issues (DSE, 2007), but more information is required to determine the relative values of strategies to retain old trees at particular densities and patterns in the landscape. The most relevant information concerns the roles of old trees among established regrowth: hence retrospective studies are likely to be more useful than planned experiments for generating the required information within a realistic time-frame (Loyn, 2004).…”

“…Examination of these stands and their use by fauna allowed the relative values of particular densities and spatial patterns of old trees to be assessed, within a 60-year regrowth matrix. In particular, we hoped to distinguish whether birds were related positively or negatively to increasing numbers of old trees, and to determine whether any positive relationships were convex, concave or linear (Loyn, 2004). Convex relationships (perhaps revealing themselves as positive intercepts on the y-axis) would imply that even scatters of old trees among regrowth were more useful to the birds under consideration than clumped distributions of the same number of old trees.…”

“…Lindenmayer and Franklin (2002) discussed systems of aggregated or dispersed retention on logging coupes, along with other strategies for retained systems, while Loyn (1985aLoyn ( , 2004 considered the relative merits of integrating or segregating conservation and production, at a range of spatial scales. All recognise the need for combinations of strategies at different spatial scales.…”