What proportion of the forest of small-scale owners is likely to be harvested: a Whanganui case study

Abstract

National and regional wood supply forecasts indicate that small-scale forests will provide an increasing proportion of New Zealand's harvest volumes over the next decade. However these forecasts are based on physical factors only and do not consider harvest costs. Because of size, location and terrain, some small-scale forests may not he economic to harvest. In a case study, carried out in Whanganui District, the delivered wood cost including harvesting, roading and transportation, was estimated for a sample of 58 small-scale forest blocks. Taken into account were the size, slope, location and roading requirements of each block. Initial analysis, assuming harvesting at age 30 years, found a distribution of costs, with the majority of blocks in the range $53 a tonne to $87 a tonne, with an average of $70 a tonne. However there were five blocks with delivered wood cost exceeding $100 a tonne. The optimum rotation age for these five blocks was found to be at least 49 years at which age costs are $89 a tonne to $107 a tonne. Given that average market prices for logs over the last five years in the region have been $84 a tonne, it is probable that these blocks will only be harvested at old ages and at times of exceptionally high average log prices. This study is based on generic assumptions about silviculture, yields and market destinations. However it indicates that five to 10 per cent of the area of small-scale blocks in the Whanganui District may never be harvested.