小流域治理20年后千烟洲生物量的变化

小流域治理前,千烟洲植被以草丛为主,间有小部份灌丛,生物量极低。自1982年实行小流域治理至今,千烟洲生物量有了极大提高,植被覆盖率也显著增加,林地面积从1982年底的0.4%提高到1999年底的93.3%。乔木层每公顷胸高断面积为27.63m2,其中马尾松、湿地松、杉木、板栗及枫香这5种人工树种共占84.3%,这表明全站植物生物量主要由人工林决定。天然次生林中,格药柃单位面积胸高断面积最大。用相关生物量模型计算全试验区4个优势种地上部分生物量之和为32035t。其中湿地松生物量最大为25990t,占81.1%,枫香最小为874t。

Change of Biomass in Qianyanzhou After 20 Years of Small Watershed Treatment

Small watershed treatment has been implemented in Qianyanzhou(QYZ) Jiangxi Province since 1982. As a result, structure of plant communities and species diversity showed significant changes, especially biomass. Before 1982, the vegetation was dominated by herbs dotted with a few species of shrubs, but without any arbors, and the biomass was therefore extremely low. Current situation is thoroughly different, the forest cover increased to 93.3% by the of 1999 from 0.4% in 1982. In addition, the total basal area reached 27.63 m~2/hm~2 in 2003,of which, 84.3% was taken up by planted tree species, Pinus massoniana, P. elliottii,Cunninghamia lanceolata, Castanea mollissima and Liquidambar formosana. This reveals the results of small watershed management. The basal area of Eurya muricata reached 1.11m~2/hm~2,which was larger than that of other natural_regeneration species. Several biomass models of tree populations were used to calculate the above_ground biomass of all species except for Castanea mollissima. The results showed that the biomass of P. elliottii ranked the highest 25 990 t followed by P. massoniana and Cunninghamia lanceolata 3 961 t, 1 210 t respectively.And L. formosana, 874 t, was the lowest.