Since the Plaza Accord,structural changes in timber ­ roundwood and lumber ­ imports have had significant influences on the sawmill industry in Japan. This study aims to clarify changes in the scales and locations of sawmills in Japan considering the structural changes, focusing on roundwood procurement from 1985 to 2010. Results of this study are as follows: (1)based on statistical data analysis, regional characteristics became remarkable about sawmill scale and kind of roundwood procurement. (2)We classified prefectures which had large-scale sawmills (beyond 300kW) into four types, ①Quantity of Roundwood Procurement (QRP) was increased and Domestic Roundwood Rate (DRR) was high, ②QRP was decreased and DRR was high, ③QRP was decreased and DRR was low, ④QRP was increased and DRR was low. Large scale sawmillʼs procurement share was increased nationwide but this trend only indicated a few big companyʼs operations. Almost sawmills using imported roundwood were decreased and changed in the business characteristics from lumbering to small lot production of many products with additional values, distribution or real estate businesses. Though half of amount of domestic roundwood was procured by small and medium-sized sawmills (within 300 kW), there were big regional differences of the feature in prefectures and scale of sawmills processing domestic roundwood in the production area for ordinary quality roundwood has been expanding remarkably for the 2000’s.

In the Kyoen River Delta, trees including Koyo poplar (Populus euphratica) had been extensively logged for building materials and fuel wood for military use from the 1940s to the 1980s. As a result, Koyo poplar has been designated as an endangered species. Here, we determined the current distribution and recovery trend of Koyo poplar based on Landsat data obtained in 1977, 1990, 2000 and 2010. We also attempted to identify areas suitable for planting. Koryu tamarisk (Tamarix ramosissima) is a pioneer species along rivers and provides a protective habitat for Koyo popular, which later becomes the climax species. A geographic information system (GIS) analysis showed that, as of 2010, human disturbance of the forest had almost ended and vegetation was recovering. Succession to Koyo poplar had started in some areas. A buffering analysis by GIS showed that it would take at least 450 years for Koyo poplar to recover in Koryu tamarisk forests. That means that the recovery would take 10 times as long as the period of disturbance. However,previous studies have shown that mixed planting of Koyo poplar and other tree species improves the growth of Koyo poplar seedlings and that root cutting improves bud blush from roots. The regeneration period for Koyo popular could be shortened by planting Koyo poplar in Koryu tamarisk forests along rivers and by root cutting in Koyo poplar forests that had stopped regenerating.

We investigated profit differences among privately owned sugi (Cryptomeria japonica) plantations with different cross-cutting strategies and management conditions in Sampoku District, Murakami City, Niigata Prefecture, Japan. First,we simulated cross cutting to maximize gross monetary yield for two cross-cutting strategies reflecting demand, and four forest management conditions reflecting the frequency of pruning. Second, we calculated profit, subtracting total cost depending on location. For a cross-cutting strategy in which primarily sizes of cheaper logs were produced and supplied stably, the effect of management conditions on profit was small and the risks were easy to manage. However, a strategy in which expensive large logs were produced in addition to cheaper logs was more profitable for stands of better site classes and management conditions. Therefore, forest owners must understand demand accurately to choose an appropriate cross-cutting strategy and keep future forests in good condition by required pruning.

n this study, we attempted to use a simple method to interpret forestry work road networks from aerial photography images that were acquired by a small, unmanned multicopter, and to construct geographic information system (GIS) data for these locations. Ortho-mosaic images were made from multiple aerial photography images. These images were high resolution (about 3­5 cm per pixel), and the forestry work road network locations were apparent on these images. We used GIS software to draw polylines on places that we were able to interpret as forestry work road network locations in these images. As a result, the GIS data of the forestry work road network locations that we constructed had less than a 1.0% error rate compared with surveying results. The advantages of using a small, unmanned multicopter are that anyone can easily make high-resolution, ortho-mosaic images and, thus,can inexpensively acquire high-precision GIS data for forestry work road networks. We are convinced that using a small, unmanned multicopter is an effective technique for interpreting forestry work road networks. Therefore, we anticipate that these multicopters will contribute to forest management by serving as tools that can collect information, which can be fed back to a GIS, about the day-to-day changes in forests that result from forest management treatments.