Structural characteristics and population dynamics of deciduous forest on high terrain of Mae Moh sulfur dioxide polluted project area, Changwat Lampang
1996
Waranyu Ratchareon
Structural characteristics and population dynamics of deciduous forest on high terrain of Mae Moh sulfur dioxide polluted project area, Lampang was investigated during March 1993-August 1994 by setting the eleven sample plots of 40*40 square m (1600 square m) at Jae Hom (PC) and Mae Moh (PW1-PW5 and PR1-PR5) which were followed by the contour line of SO2 concentrations (0, 100, 200, 300, 500 and 1,000 micro g/cubic m). Trees, which DBH exceeds 4.5 cm, contained in each plot were mapped, species recorded and the DBH, heigt and heigt to the first main living branch (Hb) were measured. Tree density in the eleven plots were varied between 100-1288 trees per hectar. Three dominant species; Tectona grandis Linn. f., Pterocarpus macrocarpus Kurz and Xylia xylocarpa Taub. were found mostly in all sample plots. The distribution of DBH and H were nearly in L and bell-shaped, respectively. The forest characterized by 2-3 layers in each plot. The crown covers were not continuous. All plots, except PW5, had lower species increasing rate, diversity index, the richness index and the evenness index than the control plot. The spatial arrangement of both total individuals and the three dominant species showed varied distribution patterns, which were uniform, random, clumped and non-distribution. The population dynamics were not different in the 11 plots, 4 plots gained, 3 plots lost and the other 4 plots were dynamics equilibrium. All plots presented had similar patterns of tree mortality rates but differed in species death and recruitment. According to the statistical data from filed observation, structural characteristics and population dynamics were unlikely affected by sulfur dioxide concentrations within the studied period in the proposed area.
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