Establishment of the Box-Ironbark ecological thinning trial in north central Victoria

An ecological thinning trial was established in 2003 in north-central Victoria as part of the development of an ecological management strategy to support the newly created Box-Ironbark Parks and Reserves System. The objective of the trial was to restore diversity of habitat structure to declining Box-Ironbark forests and woodlands. Three ecological thinning techniques were designed around several principles: reducing total basal-area of trees and retaining levels of patchiness whilst retaining large trees. Thinning treatments were implemented in 30 ha plots at four conservation reserves south of Bendigo, Victoria. A range of ecosystem components were monitored before and after thinning. A woody-debris removal treatment was also set-up at a 1 ha scale within thinning treatments. Prior to thinning, plots were dominated by high numbers of coppice regenerated trees with few of the trees sampled considered large, resulting in low numbers of tree hollows and low loadings of coarse woody debris. It is anticipated that the establishment of the ecological thinning trial (Phase I), is the beginning of long-term monitoring, as effects of thinning on key habitat values may not be apparent for up to 50 years or more. The vision for restoration of Box-Ironbark forests and woodlands is one of a mosaic landscape with a greater diversity of habitat types including open areas and greater numbers of larger, hollow-bearing trees. This paper summarises the experimental design and the techniques adopted in Phase I of this project during 2003-2008.