RESOURCE MANAGEMENT DIVISION DOF PNG

Resource Management Division of the Department of Forests PNG

The majority of work undertaken by the Department of Forests in the field of resource management had been the surveying and assessment of the resources and the acquisition of suitable areas for development.

Forest Inventory

The usual purpose of a forest area assessment is to determine as precisely as available time and money will permit, the volume of standing trees in a given area. To attain this objective, requires a reliable estimate of the forest area and measurement of all or an unbiased sample of trees within this area.

In PNG there were three types of inventories (reconnaissance, resource inventory and working plan) based on the planned use of the forested area in question. Aerial photographs are an essential part of these activities.

Inventory planning checklist included:

• Purpose of the inventory. • Background information. • Description of the area to be assessed. • Information required from the assessment. • Inventory design. • Measurement procedures • Compilation and calculation procedures • Reporting of results, maintenance, and storage of records.

In more recent years, the emphasis shifted to the preparation of detailed harvesting plans to ensure greater utilisation of the forest resources and to ensure rehabilitation of the regenerative capacity of the forest for the next harvesting cycle.

Resource inventories in PNG were initially undertaken to provide information concerning the size of the resource and its commercial log volume content based on sampling at a very low intensity which rarely exceeded 1% and has often been less than 0.1%. The mean commercial volume over 50 cm girth over buttress and bark (sometimes converted to diameter over buttress and bark) and occasionally the mean volume of trees less than 50 cm girth over buttress and bark was calculated. With the results, suitable correction factors were used to allow for sampling errors etc. Volumes were calculated in forest inventories from a tree volume equation developed by Evan Shield55 in 1965 from work undertaken in his dissertation at the Commonwealth Forestry Institute Oxford from data supplied by the Department of Forests.

55 Shield E H 1965, The application of new sampling methods to previously inaccessible tropical forest areas, with particular reference to Papua New Guinea. Commonwealth Forestry Review vol 55 No 1 March 1976.

47