The current IFOAs specify that logging can only occur under specified silvicultural practices including Australian Group Selection, Single Tree Selection, Thinning and Alternate Coupe Logging. These silvicultural practices focus on the process for undertaking harvesting operations rather than ensuring that improved environmental and sustainable forestry outcomes are delivered. The IFOA remake proposes a new multi-scale landscape approach to threatened species management and will set harvesting intensity limits on basal area removal and harvest return times. Under the trial, the requirement for specific silvicultural treatments was removed and a range of harvesting intensity thresholds was applied.
The setting of thresholds for harvest basal area retention is an important factor in ensuring that the new IFOA conditions will achieve the dual purposes of ensuring that harvested areas are adequately regenerated and that important ecological and habitat features of forests are retained and protected. For some forest types, such as those dominated by species including blackbutt, higher levels of sites disturbance and access to sun light are required to achieve adequate regeneration for timber production purposes.
The harvesting intensity thresholds applied during the trial will be assessed in combination with multi-scale landscape threatened species protections to ensure that forest structural diversity, mature forest elements, and landscape connectivity are maintained during timber harvesting operations. The harvesting intensity thresholds will also be assessed to ensure that they provide adequate settings for regeneration for timber purposes.
The trial established three zones that specified thresholds for harvesting intensity depending on past logging history, the regeneration needs of the forest and the structural diversity of the forest. It included:
- lower intensity harvesting practices in the existing non-regrowth forest zone, and
- establishing two thresholds for harvesting intensity within the existing regrowth zone:
- higher intensity harvesting in blackbutt dominated areas
- lower intensity harvesting in all other areas.
Higher intensity (higher basal area removal) harvesting was applied in blackbutt dominated forests in a limited number of trial sites. A range of retained basal area thresholds, rather than 'removal' thresholds, were also tested during the trial, which may have delivered more intensive harvesting practices in a small subset of the trial sites.
Notably the conditions trialled were designed to ensure that intensive harvesting would be balanced by the implementation of the new multi-scale landscape approach, which includes improvements to the retention of hollow-bearing and recruitment trees, feed trees, wildlife habitat clumps (unlogged habitat patches) and a range of threatened species and habitat protection measures.
The trial did not permit clear-felling operations and was limited to the five harvest areas (or compartments) in the Lower North East Region that will be approved by the EPA.