Forest Vegetation Structures and Successional Trends in Young-il Soil Erosion Control District

摘要

Structural characteristics and successional trends of actual forest vegetation in Youngil soil erosion control district, South Korea, were studied and described by the phytosociological investigations and diameter measurement. And also the incrementalgrowth pattern of the major trees for erosion control analyzed using increment core. Sixty-eight releves were sampled with 100m2 plots. Two main vegetation types (Lespedeza bicolor-Miscanthus sinemis-type and Alnus firma-Styrax japonica-typs) have beendistinguished and typified nine vegetation units. Constancy classes diagram showed that the higher species (^IV) have only 2.6% and that most species occurred were rare and had low abundances. The successional trends of the actual forest vegetation wouldbe mostly changed as Quercus serrata forest. Annual diameter growth was 3.0-3.4 mm in case of conifer (Pinus rigida and Pinus thunbergii), and the broad-leaved trees (Alnus firma, Robinia pseudo-acacia, and Alnus hirsuta) showed 4.3-4.9 mm. The incremental growth patterns showed to be decreased rapidly since twenty to twenty-five years regardless of the species of trees.