Site Classification for Sugi Plantations using GIS

This study aims to evaluate the effects of topographical factors on tree height growth and to classify stands of sugi (Cryptomeria japonica D.DON) into different site classes with Geographic Information System (GIS) analysis. To evaluate these effects, seventy-four plots (10 by 10m) were established in the study area. Calculations for all plots showed that the mean site index for northerly aspects is greater than for westerly and easterly aspects, and the lowest is for southerly aspects. Also, mean site indices are lower the closer the stand locations are to ridges. The lowest mean site indices are those of stands located within 10m of ridges. Next we classified sugi stands into three classes according to slope aspect and location on slope respectively. Integrating the two topographical factors with the growth data, sugi plantations were classified into four site classes: Class I , Class II, Class III and Class IV. GIS technology was used as an efficient means of performing geographical analysis, classifying sugi stands on the basis of topographical factors, and displaying the results.