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Abstract
We investigated conifer plantation management in Japan using high-resolution airborne data based on an individual tree crown (ITC) approach. This study is the first to apply this technique to Japanese forests. We found that forest resources can be measured at the level of a single tree. We also produced a tree-crown map for a test site with Chamaecyparis obtusa, Pinus densiflora, Larix kaempferi, Cryptomeria japonica, other conifers, and broadleaved trees, with a classification accuracy of 78%. Forest-stand polygons with tree-cover types were generated from this map, a tree-density map, and a crown-occupied-area map. Forest information for the stand polygons was extracted automatically and compared with detailed field-survey data. The error between our ITC estimates and the field-survey data ranged from 0.3 to 30.2%, depending on tree crown size, density, and other factors. Errors were highest for high-density stands with mixed compositions and tree crown diameters ≤5.0 m. However, the error for stands with crown diameters ≥6.2 m was 11.6% or less. Therefore, this technique is best suited to pure Japanese conifer plantations without multiple layers or high-density stands.
Acknowledgments
We thank D. Hill, S. L. Grey, R. D. Sharma, H. J. Barcley, and the members of the Digital Remote Sensing team, Pacific Forestry Centre (Canadian Forest Service) for useful suggestions during image analysis. We also thank the members of the forest measurements and planning laboratory, Shinshu University, for allowing us to conduct the field investigation. This study was supported by a grant–in-aid for Scientific Research from the Japan Society for the Promotion of Science (no.18580141). UCD data were offered free of charge by PASCO Corporation for this research.
