Topography of a large-scale research plot established within a tropical rain forest at Lambir, Sarawak
Topography of a large-scale research plot established within a tropical rain forest at Lambir, Sarawak
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作者：
T. Yamakura
最近在马来西亚东部沙捞越的Lambir山建立了一个52公顷的大型研究地块，用于对热带雨林进行长期生态研究。1990年11月开始了包括地形测量在内的地块划界工作，一直持续到1992年3月。采用带自动测距仪的电子测距仪，在陡峭复杂的斜坡上建立了可靠的精度。将500 m × 1040 m的样地划分为1300个20 m × 20 m的样方，再划分为20,800个5 m × 5 m的亚样方。按照传统的陆地测量方法，用测速仪仔细测量了各个地标底部的罗盘方向和天顶角。由此获得的地形数据被转换成每个地标的高度值。最低点和最高点之间的海拔高度差约为100米。150米利用这些高度数据绘制了地形图。此外，一个几何平面，覆盖1,300个样方的数字确定计算地形变量的详细统计，如海拔，方向，角度和凸度的斜坡。这些变量的统计数据和它们在样地内的分布图表明了样地的陡峭、起伏和复杂的坡度地形。这些地形特征似乎导致了植物栖息地的破碎化，并可能与丰富的Lambir雨林植物群紧密结合。
A large-scale research plot 52 ha in area was recently established at the Lambir Hills for a long-term ecological research of tropical rain forest in Sarawak, East Malaysia. The work for plot demarcation including a topography survey was initiated in November 1990 and continued till March 1992. Electronic tacheometers with automatic distance meters were adopted to built the plot with reliable accuracy on steep and complex slopes. The plot with an area of 500 m × 1040 m was divided into 1300 quadrats of 20 m × 20 m and further divided into 20,800 subquadrats of 5 m × 5 m, by setting landmarks at all the comers of quadrats and subquadrats. The compass directions and zenith angles to elevation at the base of respective landmarks were carefully surveyed with tacheometers by following conventional land survey methods. The topographical data thus obtained were transformed into altitude values at each landmark. The altitude difference between the lowest and highest points in the plot was ca. 150 m. A topography map was drawn by using these altitude data. Furthermore, a geometrical plane covering each of 1,300 quadrats was numerically determined to calculate the detailed statistics of topographic variables, such as the altitude, direction, angle, and convexity of slopes. The statistics of these variables and their distribution maps within the plot suggested the steep, undulating, and complex slope-topography of the plot. These topographic features seemed to result in the fragmentation of plant habitats and might be strongly combined with a rich flora of the Lambir rain forest.