Planning methods for sustainable management of timber stocks in Papua New Guinea's forests

• Papua New Guinea Forest Research Institute, Papua New Guinea
• Southern Cross University, Australia
• Queensland Forest Research Institute, Australia
• Australian National University, Australia

Papua New Guinea has over 28 million hectares of tropical forests. These forests play an important role in the conservation of tropical biodiversity and in the livelihood and development of rural and forest dwelling communities. Up to 40% of PNG forests are considered exploitable for timber production with current technology.
There has been a rapid growth of forest harvesting and log export since the 1980s and this has led to major policy reforms in PNG. However, plans on how to use forest resources remain rudimentary and the implementation of policy reforms has been difficult. Consequently, there has been over-cutting of forests, depletion of resources, a heavy environmental impact, and a long-term impact on the future of forest-dependent communities.
For policy and regulatory reforms to be effective, these need to be underpinned by improved planning systems that will integrate national and regional conservation, customary owners, forest companies and small-scale users of forests.

The goal of this project was to assist PNG to better manage its native forest resources through the introduction of improved technology and through the enhancement of its scientific, technical and management capacity. The project used technology, planning experience, and management techniques developed for Australian native forests and adapted them to areas that are typical of PNG forests.
Much of the methodology developed in this project could also be applied to the calculation of carbon stocks.

Australian and PNG Forest Authority (FA) staff assessed areas that had been harvested for timber in a study region in PNG, then analysed and reviewed the forest-inventory methods that were used and train staff in improved inventory techniques.
The team sampled trees from the 10 most important timber species in the area, developed new equations to calculate timber volume for these species, and trained staff on how to develop new volume equations for species. They incorporated species recruitment and species mortality functions from a north Queensland forest growth model, and the equations derived from the 10 important timber species, into the PINFORM forest growth model. This model was then integrated into current planning systems in PNG.
The team also collected data from sample plots in areas that had not been logged -conventionally logged or subjected to small-scale logging. They used these data to calibrate models and assess the impacts of alternative management options.
Australian and PNG forest planners and researchers determined whether forest-management planning systems used in Australia could be used in PNG. They also conducted workshops in PNG to provide training and consultation on how to develop and apply planning systems, and two PNG FA staff received additional training in Australia.

This project resulted in increased capacity and knowledge within the PNG government for forest planning and inventory, and improved systems to analyse alternative options for timber harvesting. Key outputs included:
A major review of forest area assessment, inventory and planning systems used in PNG.
Re-measurement of 32 large permanent sample plots in cut-over native forests across PNG. Data from these plots have been used to assess the response of forests to harvesting and to develop new functions for a forest growth model. This information is being used to inform policy decisions on the future use of forests in PNG. The data management system for PSPs was revised and updated.
Growth model analysis, which suggests that the 35-year cutting cycle in place in PNG is probably too short to allow for commercially viable future harvests if all trees greater than 50 cm DBH are cut. Longer cutting cycles, higher diameter limits for species that can reach larger sizes, leaving a proportion of current commercial trees for future harvest and reducing harvest impact will provide for more economically and ecologically sustainable timber harvesting.
An analysis that compared timber volumes assessed in forest inventory with actual harvest volumesto determine the cause of differences between these. This kind of analysis is now being applied more widely, to develop estimates of timber resources that more closely reflect industry harvest performance and more realistic estimates of future yield and annual allowable cut.
A revised strategic forest inventory method that will result in cheaper and more accurate inventories of future project areas.
A simple system to integrate existing forest area, inventory and growth information. This system produces more reliable estimates of future timber yield under different harvesting scenarios for incorporation into forest planning and project documents.
More capable and trained staff in the PNG Forest Authority, Forest Research Institute and the Department of Environment and Conservation, who are able to undertake improved analysis of forest inventory information and forest management options.