大山山頂付近のキャラボク自生地の土壌特性

There are several alpine plants grow on the summit of Mt. Daisen stretching over Tottori and Okayama prefectures. Among the alpine plants, Taxus cuspidata var. nana is specified as a national natural monument. The alpine plants are of academic important and consist unique landscape of the summit of Mt. Daisen. However, as the number of mountain trekker increased because of a mountain trekking boom started from１９７０th, degradation of the vegetation and soil on the summit of Mt. Daisen accelerated. Then, in present, a group protecting the summit environment of Mt. Daisen has worked on the rehabilitation and protection collaborating with citizens, local government and so on since １９８６. In order to implement the work efficiently, we need to understand the environmental condition and they have conducted researches on vegetation but on soil. They conducted a soil survey just only one time in１９８６. In the present study, we tried to evaluate the present status of soil properties of the site, where the Taxus cuspidata trees have naturally grown for a long time, comparing with the former survey data. The results of the soil properties showed that Soil fertility was generally very low. Besides, soil pH was strongly acidic and might advance acidification of the soil comparing with the data in１９８６. Total carbon and nitrogen tended to increase comparing with those in１９８６, but available P and exchangeable cations tended to decrease. These results indicated that the plants survive on a fragile soil environment might be degrading.