| In this paper, the whole forest area of Three Gorges Reservoir Area as study area,combining with field survey 109 sample plots, stem analysis data of 95 trees for 7 treespecies or forest types was acquired, and biomass growth model of major trees wasestablished. Basing on the Three Gorges Reservoir Area forest inventory data in 1999, aGIS system of vegetation Distribution of Three Gorges Reservoir Area was established,and the statistic models between the annual mean temperature/precipitation and latitude,longitude and altitude were established for Three Gorges Reservoir Area, by applying thedata from 17 meteorological observation stations.Then the distribution patterns ofbiomass and productivity of Three Gorges Reservoir Area major forest types wereanalyzed. The main results showed:1. In Biomass of all vegetative organs of different tree species, the proportion of stem isthe biggest, and other vegetative organs could vary with the trees. With the increment ofbiomass of individual tree, proportion of vegetative organs does not increase or reduceevidently. The trend of proportion of branch and proportion of stem were contrary, whilethe trend of proportion of branch and proportion of leaf were the same. Proportion of roothas little effect on other vegetative organs. The Biomass of different layer within stand isin the order as: tree＞litter＞shrub and herb. For shrubbery, the order was shrub and herb＞litter.2. In the Yangtze Three Gorges Reservoir Area, the LAI of various forest types fromhigh to low is: bamboo forests(34.15)＞evergreen broad-leaved forests(9.02)＞deciduousbroad-leaved forests(4.48)＞Chinese-fir plantation(4.09)＞coniferous-deciduous mixedforests (4.05)＞temperate pine forests(3.78)＞coniferous mixed forests(3.47)＞Cupressusfunebris forests(3.20)＞Pinus massoniana forests(2.20).The results showed that there is agood linear relationship between Leaf Areas and biomass within arboreal forest.3. The total forested area in Three Gorges Reservoir Area (shrubbery and economicforests) is 2.69×106hm2, which makes up 50.37％of the total area of Three GorgesReservoir Area. Among those, arboreal forest makes up 33.25％, and the totallive-biomass and the total productivity were 117.40×106t and 17.68×106 t·a-1, respectively.The indices make up 1.10％and 5.31％of that of Chinese forests, respectively. The ordersin the total biomass of various vegetation types are as following: Pinus massonianaforests(35.27％)＞deciduous broad-leaved forests(14.18％)＞shrubbery(12.95％)＞coniferous-deciduous mixed forests (10.43％)＞coniferous mixed forests(9.57％)＞evergreen broad-leaved forests(4.99％)＞economic forests(3.99％)＞Cupressus funebris forests(3.56％)＞Chinese-fir plantation(2.51％)＞temperate pine forests(1.50％)＞bambooforests(1.08％); The orders in the total productivity of various vegetation types are asfollowing: Pinus massoniana forests(30.65％)＞shrubbery(25.86％)＞deciduousbroad-leaved forests(10.92％)＞coniferous mixed forests(8.24％)＞coniferous-deciduousmixed forests (7.57％)＞economic forests(4.08％)＞evergreen broad-leavedforests(3.52％)＞Cupressus funebris forests(2.91％)＞Chinese-firplantation(2.57％)＞bamboo forests(1.88％)＞temperate pine forests(1.79％). The averagebiomass of evergreen broad-leaved forests is the highest, which reach 85.6t·hm-2, andshrubbery is the lowest, which reach only 18.68 t·hm-2; The NPP of bamboo forests is thehighest, which is up to 10.10 t·a-1·hm-2, and the least one is Cupressus funebris forests,which is only 4.21 t·a-1·hm-2.4. As a whole, in Three Gorges Reservoir Area, the spatial patterns of biomass andproductivities of vegetations is high in the west and low in the east, high in the north andlow in the south. The area where biomass is Relatively high can be divided into 4 regions:north Xingshan and Wuxi, where is joined to Shennongjia; moping area of Zi gui-Lvcongpo area of Badong- South Wushan; North wu long-south fu ling-south Fengdu-southShizhu; The area of Si mianshan, where is in south Jiangjin. The biomass of Badong,Wuxi, Yiling, Fengjie, Xingshan, Shizhu, Fuling and Zigui account for 60.66％of theReservoir Area total, Among which Xingshan, Badong, Yiling are ranked at the top three,and all of them have biomass over 9.06×106t. The bottom ten account for only 11.5％ofthe Reservoir Area total; The productivities of Badong, Wuxi, Yiling, Fengjie, Xingshan,Shizhu, Yuyang and Zigui account for 59.09％of the Reservoir Area total. Dadong,Wuxi, Yiling are ranked at the top three, all of them have productivities over 1.00×106t·a-1. The last ten account for only 12.06％of the Reservoir Area total.5. With the increase of the altitude, the biomass and productivities of vegetationsincreases at first, and reduces afterwards, and there is little vegetation over 2700m. Thetotal amount was mainly distributed in 300-1500m, and the value reached 81.51×106t,which make up 83.58％of that of Three Gorges Reservoir Area. The highest amount ofaverage biomass was observed in the 1500m～1800m (59.05 t·hm-2), and the lowest valuewas found in 2400m～2700m (33.33 t·hm-2). The total productivity of stand was alsofound in 300m～1500m, which is 10.38×106t·a-1, accounting for 83.83％of the ReservoirArea total. In 900m～1200m, the amount of stand NPP is 7.07 t·a-1·hm-2, which is thehighest, and the lowest amount was found in 2400m～2700m, which is 5.62 t·a-1·hm-2.6. Applying the GIS, the distribution map of biomass and NPP of the major vegetationtypes was drawn in the Three Gorges Reservoir Area, and the scaling from individual to community, then to region was preliminarily achieved, which provided the availablemethod and technology for the mapping of vegetation productivity of larger region. Wecan conclude through comparative productivity distribution map that the distributionpattern of biomass and productivity of vegetation showed a similar pattern with that ofaltitude and Rainfall. At last, the main factors affecting the growth and spatial distributionof vegetation are altitude and Rainfall in Three Gorges Reservoir Area can be judgedpreliminarily by above conclusion.
|
PDF Full Text Request