Characteristics of vegetation according to the micro-climatic conditions of a lava pit on Jeju Island

Abstract

<p>Jeju Island is a volcanic island created by the eruption of a lot of basaltic lava through plume activity. Lava pits come in many shapes and sizes and have unique environmental conditions. This study aimed to examine the vegetation characteristics of various lava pit microclimates of Geomunoreum lava tube system formed 100-300 thousand years ago, and is one of the largest on Jeju Island. Seven plots on Geomunoreum surveyed using the belt transect method, and air temperature and relative humidity were also collected for each plot. The similarity index of the lower area (plot 3) and outside flattening-out areas (plots 6 and 7) were 14.6% and 17.5%. The lower area has the highest mortality and lowest growth rates, and therefore having a simple structure compared to other areas, with no observed changes in dominant species. At the midpoint areas (plots 2 and 4) the dominant species transitioned from <em>Quercus glauca </em>to <em>Acer palmatum</em> and <em>Camellia japonica</em>. The species composition of the shrub and subtree layers remained almostly unchanged. At the higher areas (plots 1 and 5), changes in species composition were frequently observed in all layers. At the outer flattening-out areas (plots 6 and 7), the lowest mortality and highest growth rates were observed, the variety of competing species were high diverse in the tree layer. The daily average temperature of plot 3 (low) and plots 6 and 7 (flattening-out areas) ranged from 4.1℃ to 13.2℃, and the daily average humidity ranged from 1.2% to 39.3%. The simple vegetation structure of the lower area can be attributed to this low temperature and high humidity. The concluding observation is that on the Geomunoreum lava pit, areas where microclimate conditions remain fairly constant, there is no dramatic change in vegetation compared to the perimeter. These characteristics are not always observed on other lava pits on the island.</p>

A Study on the Drought Occurrence Characteristics in Volcanic Island Regions: The Case of Jeju Island

“…제주지역은 섬이라는 입지적 여건(장마의 이동선상 및 태풍의 길목에 위치하는 등)과 한라산이라는 특수한 지역적 특성으로 인해 기후학적으로 강수량이 많을 수밖에 없는 조건에 해당한다 (Seo et al, 2014;Park and Lee, 2016). 이때 우리나라의 평균적 강우 방향성을 고려해 보면 (Park, 2012)…”

“…가뭄 피해는 종료 시점을 예측하기 어렵기 때문에 농작물 피해 등이 장기간 에 걸쳐 2차, 3차로 나타나기도 한다. 가뭄 대응과 관련하여 가장 큰 문제는 지역단위에서 가뭄 대응 정책이나 대책을 마련하는 것이 쉽지 않다는 것이다 (Park and Lee, 2016).…”