Estimation Of BVOCs Emission From Forests In Shaanxi Province

This study measured six tree species BVOCs emission rate, and collected other tree species reference emission rate.Then converted the volume data of dominant forests to leaf biomass data, used Guenther’s BVOCs emission model to estimated BVOCs emissions in Shaanxi. BVOCs emission inventory from forest was established, and emission source was analyzed.The results provided theoretical reference for choosing environmentally friendly tree species, and for better understanding a series of current environmental problems in Shaanxi.The main results were as follows,1. Cedrus deodara and Pinus tabuliformis had high monoterpene emission rates, Platycladus orientalis, Metasequoia glyptostroboides, Pinus bungeana and Sophora japonica had moderate monoterpene emission rates; and just Cedrus deodara had high OVOCs emission rate.2. BVOCs emissions from forest in different cities was in the order of Hanzhong > Ankang > Yan’an > Baoji > Provincial units > Shangluo > Xianyang > Xi’an > Weinan > Yulin > Tongchuan.3. In 2010, the annual total BVOCs emissions in Shaanxi was estimated to be 1190.78 Gg C, composed of 1019.20 Gg C(85.59%) isoprene, 61.97 Gg C(5.21%) monoterpene, and 109.60 Gg C(9.20%) OVOCs.4. Based on BVOCs standardized emission fluxes of forty-four forest types, seven forest types had high BVOCs emission intensity, seventeen forest types had moderate BVOCs emission intensity, twenty forest types had low BVOCs emission intensity.5. Based on the BVOCs emission characteristics of Shaanxi province, we concluded that, isoprene was the main compound among all the three categories produceted by forest in Shaanxi, with a contribution of 85.59% to total BVOCs emissions. Hanzhong city was the main emission source among the eleven cities of Shaanxi, making up 18.07%; Oak forest was the main emission source among the 44 forest types, accounting for 67.55%. Summer gave the highest emission amount among four seasons, with a percentage of 66.23%, and July produced the highest emission amount among the twleve months, contributing 24.42%. Middle age structure of the trees was the main emission source among the five types, with a contribution of 31.84%.