日本森林技術協会の森林・林業分野におけるリモートセンシングの活用事例

抄録

Three Japan Forest Technology Association, case studies that, demonstrate the utility of remote sensing technology for monitoring forest ecosystems, mapping the site index distributions of forest plantations, and monitoring harvested areas are presented. The first case pertains to the application of Unmanned Aerial Vehicle (UAV) imagery in the Ogasawara Islands. This approach was used to assess ecosystem conservation initiatives and to conduct vegetation surveys in regions of the Islands that are otherwise inaccessible. This case’s quantitative assessment of the expansion of the native tree canopy and the effects of the control of invasive alien plants in Takinoura, Anijima was based in a visual interpretation and analysis of time-series orthomosaic images. High-resolution UAV images were used to (i) identify the distribution of rare and exotic plant species on the island’s inaccessible cliffs and landslide areas, and (ii) analyze the relationships between the vegetation distribution and topographic conditions. The second case study presents a methodology for generating site index distribution maps based on the integration of canopy-height values derived from airborne LiDAR with forest planning maps. This approach is shown to facilitates the visualization of disparities in forest productivity across different forest subcompartments. The case provides valuable information for identifying the optimal areas for harvesting and reforestation, as well as for enhancing forest planning. The third case study focuses on the estimation of harvest area in private forests across Japan, leveraging optical satellite imagery. In this method, harvested area maps were stratified, and the presence or absence of a harvested area at randomly allocated sample points in each stratum was visually interpreted. The visual interpretation results were then used to estimate harvest areas based on statistical analyses. To mitigate the effects of interpretation bias and input errors, each sample point was independently interpreted by at least three interpreters.