Dendroecological reconstruction of the disturbance dynamics and human legacy in an old-growth hardwood forest in Korea

Abstract

The rapidly maturing forests of Korea are now in need of new management objectives to meet the increasing national demands for various ecosystem services. To properly tackle these new challenges, it is critical that we understand the historical disturbance regime that shaped the current forest structure and composition. In this study, we investigated the disturbance history of an old-growth hardwood forest on Jumbong Mountain, Korea, a designated UNESCO biosphere reserve. We used dendroecological analysis to reconstruct disturbance events of various intensities, collected historical records and interviewed long-time residents to evaluate influences from historical human activities. The results suggest that a shift in the disturbance regime occurred during the early 1900s. Prior to the 1900s, most disturbances (67%) were minor to moderate in intensity, which enabled the occasional establishment and growth release of the shade-tolerant Acer pseudo-sieboldianum and Carpinus cordata. Starting from the 1910s, widespread and intensive disturbance events dramatically increased, and continued until the 1960s, represented by strong pulse of establishment (e.g., 60% of all establishments between the 1930s and 1950s) across all major species regardless of their shade tolerance. Increased disturbances during this period coincided with similar increase in slash-and-burn farming activities, triggered by the collapse of the peasant class during the Japanese colonial era. Since the 1970s, disturbance was practically non-existent because of the successful slash-and-burn farming regulation and fire suppression policy. Results suggest that the current composition and structure of the study stand and other mature natural hardwood forests in Korea, especially those characterized by the dominance of Quercus mongolica, strongly reflect the history of both natural disturbance regimes and human legacy, and will likely continue to last into the future.