ESTIMATED BIOMASS AND PRODUCTIVITY OF NATURAL VEGETATION ON THE TIBETAN PLATEAU

We developed a methodology for linking together data from forest and grassland inventories and ecological research sites, and provided a comprehensive report about live biomass and net primary productivity (NPP) on the Tibetan Plateau, the “Third Pole” of the earth where little information about plant biomass and production had been available outside China. Results were as follows. (1) The total live biomass of the natural vegetation in the Xizang (Tibet) Autonomous Region and Qinghai Province was estimated as 2.17 Gg dry mass, of which 72.9% was stored in forests where spruce–fir accounted for 65.1%. (2) The total annual NPP of the natural vegetation in these two administrative regions was estimated as 0.57 Gg dry mass, of which grasslands and forests accounted for 69.5% and 18.1%, respectively. (3) The alpine spruce–fir forests of the Tibetan Plateau had the highest maximum live biomass of the spruce–fir forests globally, with values up to 500–1600 Mg DM/ha (including both aboveground and belowground biomass). (4) The QZNPP model generally predicted NPP well for most of the biomes on the plateau, and simulated the various Chinese vegetation divisions. Model results showed a positive reinforcing effect of monsoon climate in China where the warmest season coincides with the wettest season. (5) The live biomass map for 117 counties of Xizang (Tibet) and Qinghai and the potential NPP map for the whole plateau both showed the same decreasing trend from southeast to northwest.