Young-Moon Chun

A chamber system with automatic opening and closing for continuously measuring soil respiration based on an open-flow dynamic method

We developed an automatic opening and closing chamber system (AOCC) based on an open-flow dynamic method (open-flow AOCC). The AOCC can be used during all four seasons, even at the surface of relatively deep snow. We compared the open-flow AOCC with two closed dynamic methods [the AOCC configured as a closed dynamic system (closed dynamic AOCC) and the LI-6400 system] under field conditions. The closed dynamic-AOCC and LI-6400 measurements were about 15.4% and 5.2% lower, respectively, than the values obtained with the open-flow AOCC. There was a significant difference in soil respiration rate between the open-flow AOCC and the closed dynamic AOCC system. In contrast, no significant difference in soil respiration rate was detected between the open-flow AOCC and the LI-6400 system. In the field, the open-flow AOCC permitted continuous long-term measurements under a range of temperature conditions and did a good job of reflecting the marked daily and seasonal variations in soil respiration as a function of soil temperature.

Vegetation trajectories of Korean red pine (Pinus densiflora Sieb. et Zucc.) forests at Mt. Seorak, Korea

The vegetation dynamics of Korean red pine (Pinus densiflora) forests were investigated at Mt. Seorak, Korea. Our Detrended Correspondence Analysis (DCA) classified the forests into four types: ridge top, upper slope, lower slope/hill, and streamside. The ridge top forests were likely to sustain themselves, as suggested by the large proportion of seedlings and saplings (89% at <25 years old) and the relatively high density ofP. densiflora (2388 stems ha-1). Periodic disturbances, such as flash floods, made the streamside inhospitable to late-successional species. Such conditions may have provided a favorable environment for the recruitment ofP. densiflora seedlings through increased solar radiation and decreased competition with other species. On the upper slopes, the dominance ofQuercus seedlings and saplings (63% at >25 years old, and a density of 3263 stems ha-1) suggests a transition from pine to oak forest. Extensive human interventions appeared to arrest the natural succession from pine to oak forests on the lower slope/hill, while encouraging invasions by forest-edge and introduced species (e.g.,Rosa multiflora andRobinia pseudoacacia).

Progressive Succession and Potential Natural Vegetation on the Forest Vegetation in and surrounding Daegu, Korea

대구 인접지역 삼림 식생에 대한 진행 천이의 메카니즘과 잠재자연식생을 추정하였다. DCA에 의한 요인 분석에서는 해발고도 및 습도구배에 따라 각 군락의 특성이 결정되는 것으로 나타났으며, 토양의 수분 함량과 유기물 함량 및 전질 소량은 군락이 발달함에 따라 높아지는 것으로 나타났다. 종관 연관분석에서는 2개의 종집단으로 크게 구분되었으며, 이들 두 집단의 유형을 결정하는 요인은 기온 및 토양의 수분 요인으로 판단되었다. 특히, 두 종집단은 천이의 진행에 따라 종조성이 달라지는 군락의 발달단계를 보여주는 것으로 보이며, 생활형조성도 이를 뒷받침하였다. 입지요인 및 종조성에 따라 소나무군락, 굴참나무군락, 상수리나무군락 및 떡갈나무군락은 졸참나무군락이나 신갈나무군락으로 각각 천이가 진행될 것으로 예측되었다. 본 조사지역의 잠재자연식생은 종조성, 토양환경 및 지형요인에 의하여 산지 중·상부의 신갈나무군락, 계곡부의 고로쇠나무-까치박달군락, 산지 중·하부는 졸참나무군락의 3개 유형으로 구분되었다. 그리고 신갈나무군락과 고로쇠나무-까치박달군락은 현존 식생이면서 잠재 자연 식생이며, 소나무군락은 현재의 종조성 및 해발 영역을 토대로 신갈나무군락과 졸참나무군락으로 각각 발달할 것으로 예측되었다.

Structure and Dynamics of Korean Red Pine Stands Established as Riparian Vegetation at the Tsang Stream in Mt. Seorak National Park, Eastern Korea

The structure and dynamics of Korean red pine stands established in the riparian zone were studied in the Tsang stream in Mt. Seorak National Park, in east-central Korea. Pine stands were classified into four successional stages, the initial, establishing, competitive, and stabilizing stages, based on the age distribution of a dominant tree, Pinus densiflora, the vegetation stratification, and the microtopography of the riverine environment. The stages usually corresponded to disturbance frequencies, depending on the horizontal and vertical distances from the watercourse. Stands of the initial and establishing stages lacked tree or subtree layers, or both. As stands progressed through the developmental stages, soil particle size became finer and moisture retention capacity was improved. The stand ordination reflected the developmental stage, and the species ordination differentiated species specializing in relatively dry and wet habitats. The results of the analysis of vegetation dynamics provided ecological information which will be useful for understanding the developmental processes of vegetation established in riparian zones. Species diversity indices usually increased across developmental stages, following the typical pattern for successional processes. We discuss the importance and necessity of riparian vegetation in Korea, where most riparian forests have disappeared due to excessive human land use.