Executive Summary
This research assesses aspects of the ecological sustainability of commercial private native forestry (PNF). It does so in the context of the National Vegetation Management Framework (NVMF) in Victoria, and specifically in the case study area of East Gippsland. The work was completed in 2006.

The concepts examined here are further explored in a recent RIRDC report by Peacock (2008) on assessing the sustainability of private native forestry using biodiversity surrogates and metrics.

Who is the report targeted at?
The research presented in this report principally targets government agencies and others with an interest in approaches to assessing the ecological sustainability of PNF. It has particular relevance to Victoria and implementation of the NVMF. Some elements have relevance to landholders wishing to consider biodiversity in their management regimes; however, communication of these findings would need to be appropriately tailored and extended.

Background
The National Vegetation Management Framework (NVMF) was introduced in Victoria in 2002 with the primary goal of ‘a reversal, across the entire landscape of the long-term decline in the extent and quality of native vegetation leading to a Net Gain’ (DSE 2002). PNF fits within this broader landscape and land use context. This project, however, examines stand level indicators of sustainability and therefore cannot and does not provide a definitive statement on the overall ecological sustainability of PNF.

Aims/Objectives
The purpose of this research is to assess aspects of the ecological sustainability of commercial PNF in Victoria through the analysis of various ecological indicators. The main focus of the sustainability assessment was biodiversity.

The project comprises one part of a broader suite of projects designed to examine sustainability of PNF in Australia. The overarching project aims to:

• ensure the sub-projects have some agreed methodology for analysing ecological sustainability; and
• consolidate the sub-project findings into overall conclusions.

Methods used
The principal approach used in this research to assess the effects of commercial PNF operations on vegetation quality in Victoria was the ‘habitat hectare’ methodology. This method is outlined in the NVMF. Other indicators of sustainability were also used. The research focuses on PNF in East Gippsland as a case study.

The habitat hectare score thresholds were assessed against other sustainability criteria, which have been used in previous forest sustainability studies carried out in Victoria. The assessment determined some aspects of biodiversity sustainability of PNF using the benchmarks within the NVMF and additional sustainability indicators within the East Gippsland study area. In addition the project provided a comparison of forestry operations and other management options; for example, fire and grazing on vegetation quality using the habitat hectare scoring system.

The broader context of the influence of PNF in the landscape were not fully assessed, beyond what is required for the habitat hectare score. Other landscape studies previously carried out in Victoria indicate the importance of a mix of stand types and conditions for maximising biodiversity habitat. It is critical that this issue is kept in mind when considering the results of the project. The results provide a snapshot on the forest estate where the main variable is timber harvesting and generally ignores other landuses.

In addition to the sustainability assessments, funding was provided to complete three 1:25,000 scale maps using a comprehensive forest mapping code, which is complementary to the public forest estate mapping code. This report outlines the specifications of the code and the progress on mapping the PNF resource in Victoria.

Results/Key findings
The following provides a summary of the results from the East Gippsland PNF case study:

• All regenerated sites are estimated to have exceeded 50% of pre-harvest habitat hectares score at ten years.
• As expected following the removal of trees, harvesting had a significant impact on Large Tree and Canopy Cover component scores of the habitat hectare for the regenerating plots.

The mature tree component would increase as the forest grew to mature stand.

• Grazed sites had a significant impact on Lack of Weeds and Understorey components of the habitat hectare, while Fire had a positive effect on those components.
• Habitat hectare scores from PNF were consistent with the estimates for mature State forest.

Regenerated PNF received lower scores for Large Trees and Canopy Cover components of the habitat hectare than mature State forest, except where other component scores were similar to mature State forest. There was no comparison of regenerated PNF with similarly aged regenerating State forest.

• Thinning resulted in lower total habitat hectare scores in mature State forest, but wildfire and minor harvesting disturbances had little effect.
• Although the habitat hectare approach does not measure tree hollows, the Large Tree component provided a positive correlation with hollow-bearing trees.
• Habitat hectare scores show some sensitivity to levels of eucalypt regeneration but cannot assess adequacy of regeneration for future commercial timber production.
• The Fallen Log benchmark (at least for EVC16) would appear to be very low. This is supported by results from Statewide Forest Resource Inventory (SFRI) plots.
• Weeds (introduced plants) were not a major problem, forming very low proportions of the cover in regrowth (1.0%) or mature forest (0.44%).
• Profiles of abundance were similar in regrowth and mature forest for many plant species.
• Likewise for many fauna species, with some exceptions mentioned below.
• Arboreal mammals were twice as common in mature forest than regrowth. (But note that this difference is less than the difference in hollow-bearing trees, suggesting that other variables may limit the density of arboreal mammals in mature forest.)
• Hollow-nesting birds were about 60% more common in mature forest than regrowth. The difference was more marked for small hollow-nesters (100%) than large hollow-nesters (25%).
• Birds (total, all species except swifts) were about 50% more common in mature forest than regrowth.
• Potoroos were only detected in mature forest in this study, whereas bandicoots were found patchily in both regrowth and mature forest.
• Some relationships were evident between particular fauna species and habitat variables, such as Sugar Gliders and wattles, several species and hollow-bearing trees.

Implications for relevant stakeholders
The implications of the research findings to government agencies and others with an interest in approaches to assessing the ecological sustainability of PNF include:

• The biodiversity sustainability of PNF should be viewed in the context of the broader landscape and not just on a case-by-case basis.
• Recovery of habitat values following harvesting of the PNF resource available in East Gippsland can meet the NVMF requirements of reaching 50% of the original habitat hectare score within 10 years.
• The habitat hectare measure can provide an indication of the vegetation quality but is not sensitive enough to depict variations in stand structure between regenerating forests and mature forests or provide information on harvestable volumes.
• Diversity of vegetation species was similar between regenerating and mature PNF. Some fauna species were more closely associated with mature forest than regenerated forest. Bird abundance particularly was higher in mature forest. However, the majority of species occurred in both mature and regrowth areas.
• Similar results were achieved between PNF and State forest sites using the habitat hectare process and the other sustainability indicators.
• PNF mapping is required to incorporate the PNF resource into regional assessments of the forest estate, including yield scheduling and biodiversity enhancements. This mapping should also improve Ecological Vegetation Class (EVC) mapping in areas where there may be demand for PNF.

Recommendations
1. Communication and extension services are needed to provide information to landholders wishing to consider biodiversity in their management regimes and timber harvesting. The report highlights some significant findings for landholders to consider.
2. Further consideration should be given to the results of this investigation in relation to the assessment process, habitat recovery benchmarks and ongoing permit conditions applied to PNF operations.
3. Mapping should be completed across the PNF resource to ensure the resource is considered in the broader regional context. Such mapping could incorporate EVCs to improve the accuracy and definition of EVC mapping in areas suitable for PNF.
4. Further research could involve:

• Tracking changes in habitat hectares scores over time.
• Testing scores from a variety of sources/assessors (government agency, consultant, nonprofessional).
• Assessing logging coupes pre- and post- harvest.
• Assessing known low-value/low-habitat value area (such as, grazed paddock) and known high-value areas.
• Modelling of potential areas of PNF that may be available for harvesting in relation to the requirements of the planning system that include the Code of Practice and the NVMF.