Examining the Optimal Bucking Method to Maximize Profits in Commercial Thinning Operations in Nasunogahara Area, Tochigi Prefecture, Japan

Optimal bucking methods were applied to two operational sites of the Nasu-machi Forest Owners’ Co-operative to maximize profits, with and without taking log size into consideration, and to maximize revenues considering a new subsidy system and higher unit prices of smallsized logs. Corresponding optimum extraction rates and small-sized log prices were examined. Extraction rates from stands using the optimal bucking method to maximize profits considering log sizes were similar to the actual values, unlike the estimations obtained using other methods, e.g. without considering log sizes or maximizing revenues. However, the differences in extracted volumes and economic balances among these estimations were small and can be said to be within the error limits traditionally seen for forests and forestry conditions in the stands. The stands were about 50 years old, with an average diameter at breast height (DBH) of about 20 cm. Differences in extraction rates from stems with a DBH exceeding 20 cm were small. However, extraction rates from stems with a DBH less than 20 cm were significantly different. Therefore, the optimal bucking method to maximize profits considering log sizes could help determine the optimal extraction rates of younger stands with smaller DBHs. Possible effects of the new subsidy system and different unit prices for small-sized logs were also discussed. Both the new subsidy system and the unit prices with feed-in tariff contributed to an increase in extracted volumes of small-sized logs.