한라산 구상나무림의 식생 구조와 동태

Abstract

To document the ecological characteristics found on Mt. Halla, we examined the distribution area and geological features of Abies koreana forests. During the study, the vegetation was classified, and its structure, climatic features, and dynamics were investigated. The total distribution area of A. koreana forests on Mt. Halla was 803.6ha. These forests were distributed from 1,300, 1,400, 1,500, and 1,500m to the peak along the east, west, south, and north slopes, respectively. The area of A. koreana forests at 1,500 ‒ 1,700m along the east slope was 556.0ha (approximately 69.2% of the total area), which was the highest proportion of A. koreana forests along the mountainside. Inaddition, 70% of the A. koreana forests were distributed on slopes of less than 20° inclination. A cluster analysis indicated that A. koreana forests on Mt. Halla were characterized by three vegetation types: TypeⅠ-1, Type Ⅰ-2, and Type Ⅱ. Type Ⅰ-1 and Type I-2 vegetation (high importance value of A. koreana) exhibited a stable vegetation structure, whereas Type Ⅱ vegetation (low importance value of A. koreana) had an unstable vegetation structure. A correlation analysis between the number of seedlings and vegetation conditions (i.e., the number of A. koreana individuals, the crown coverage of A. koreana forests, and coverage of Sasa quelpaertensis) indicated that despite various correlative differences under similar vegetative conditions across several regions of Mt. Halla, the number of A. koreana seedlings was consistently dependent on the coverage of S. quelpaertensis and canopy gaps. For example, in the Bangaoreum region, the number of A. koreana seedlings was correlated with the coverage of S. quelpaertensis. Furthermore, the vegetation structure was the most unstable in this region due to a poor supply of A. koreana individuals in each vegetative layer. In contrast, in the Jindallebat region, the number of seedlings was low because of the high canopy coverage of S. quelpaertensis. However, the vegetation structure was very stable due to a consistent supply of A. koreana individuals in each vegetative layer. The analysis of the vegetation structure with altitude indicated that species diversity and the importance value of A. koreana and Sorbus commixta decreased with an increase in altitude, whereas the importance value of Taxus cuspidata and Prunus maximowiczii increased with altitude. In contrast, the species diversity and importance value of the other species in the lower layer increased with a decrease in altitude. Our results highlight that a long-term ecological study is necessary to monitor current and future changes in the A. koreana forests on Mt. Halla and to establish countermeasures that can minimize such changes.