Sustained yield, stand structure, and non-wood options after 110 years of logging in a New South Wales blackbutt forest

Summary

The history of forest management and logging regulation in New South Wales is reviewed from 1839 as a preamble to a case study analysis of three decades of measurement data (1960–1990), from over 300 continuous forest inventory (CFI) plots, located in a north coast blackbutt forest.

The plots are located in 22 865 hectares of blackbutt forest in Kendall Management Area (KMA) on the north coast of NSW, where logging has been continuous for 110 years (1880–1990), timber yields have been recorded for the last 70 years of logging, and stand volume, stocking and tree size distribution have been monitored over the last 30 years of logging. The objectives and progress of management practices, aimed at balancing wood yield against growth, and re-ordering stand stocking and size distribution to a predetermined plan are reviewed. Some future management options, including that of ecologically sustainable development, are canvassed.

Although more than 1 000 000 cubic metres of timber were harvested from the KMA over the period 1960 to 1990, indications are that the standing log volume in 1990 had not changed significantly from that standing in the same area in 1960. Thus, in gross terms, growth has balanced harvest over the whole forest in the recent 30-year period. However, there are indications that the forest was overcut prior to 1960.

In line with timber management objectives, both tree size and tree age distribution have been substantially altered toward the concept of an “ideal” stand structure, which has increased the forest growth rate.

Changing markets and community attitudes suggest that some adjustments to the “ideal” structure are warranted. An increase in the stocking density of the smaller trees to allow for increases in thinning for smallwood products, and an increase in the stocking density of the largest trees (greater than 100 cm dbhob) to provide habitat for arboreal wildlife are recommended.

Notwithstanding the long history of wood production, the option to retain many non-wood values (particularly wildlife), still appears to be open. However, management decisions to realise some of these options will need to be made in the near future, preferably within the next two cutting cycles.