제주도 곶자왈지역에 자생하는 백서향의 자생지 식생 연구

Abstract

In this study it was investigated the vegetation at the natural growth area of Daphne kiusiana Miq., a rare plant distributed limitedly to the Gotjawal region of Jeju Island. By doing so, the study seeks to provide the basic data for the preservation of the Gotjawal region such as natural habitat restoration. Large-scale habitats of Daphne kiusiana Miq. are reported the Jeoji Gotjawal in Hankyung-Ahndeuk Gotjawal region and Dongbok Gotjawal in Jochon-Hamdeok Gotjawal region. These areas were selected for this study to understand the effect of overwood on Daphne kiusiana Miq, an evergreen shrub, according to vegetation type. Also, Daphne kiusiana Miq. height and width of crown were found the highest in deciduous broad-leaved forest followed by evergreen broad-leaved forest, and black pine forest in order, in terms of vegetation type. Given this finding, it seems that, in the deciduous broad-leaved forest, Daphne kiusiana Miq. forms the top layer. As the number of Daphne kiusiana Miq. individuals changed, the black pine forest showed the largest increase in the number of individuals followed by deciduous broad-leaved forest, and evergreen broad-leaved forest in order. Based on this finding, the black pine forest seems to provide a more favorable germination environment to Daphne kiusiana Miq. Average tree height was investigated in each region. As a result, the Dongbok Gotjawal region showed almost two-times higher growth rate than that of Jeogi Gotjawal. Climate association analysis found almost no difference in the monthly average temperatures between east and west. Precipitation was twice larger on average in the Seongsan region than Gosan region, indicating potential influence on Daphne kiusiana Miq. growth. With respect to the Daphne kiusiana Miq. growth environment according to each regional vegetation type, every growth environmental aspect of Daphne kiusiana Miq. (tree height, width of crown, florescence, fruition) was found to have high values in the black pine forest of Dongbok Gotjawal region and in the deciduous broad-leaved forest of Jeoji Gotjawal region. These conditions seem appropriate for Daphne kiusiana Miq.'s growth. Evergreen broad-leaved forest showed high tree height in Jeoji Gotjawal whereas Dongbok Gotjawal had higher width of crown, florescence and fruition values. Compared with the Dongbok Gotjawal region, Jeoji Gotjawal seems to reach a stable stage where Daphne kiusiana Miq. is gradually bieng eliminated. Therefore, for the long term, Dongbok Gotjawal dominated by the black pine forest is expected to show increased Daphne kiusiana Miq. growth or number of its individuals in the succession process to deciduous broad-leaved forest or evergreen broad-leaved forest. However, natural habitat destruction is also expected because of artificial interference. In this situation, continued monitoring will be necessary to protect the natural habitat.