Application of high-resolution airborne data using individual tree crowns in Japanese conifer plantations

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 a parts per thousand currency sign5.0 m. However, the error for stands with crown diameters a parts per thousand yen6.2 m was 11.6% or less. Therefore, this technique is best suited to pure Japanese conifer plantations without multiple layers or high-density stands.