Plant biomass and productivity of Larix gmelinii forest ecosystems in Northeast China: Intra- and inter- species comparison

Wang, W.; Zu, Y.; Wang, H.; Matsuura, Y.; Sasa, K.; Koike, T.

Plant biomass and productivity of Larix gmelinii forest ecosystems in Northeast China: Intra- and inter- species comparison

2005

Databases of plant biomass and productivity of forests were prepared to make inter- and intra- species comparison in this report. Within the species of L, gmelinii, a substantial variation in plant biomass and productivity were observed in this region. The allometric relations (Y=a (D(2)H(b)) of L. gmelinii tree were essentially affected by sites and forest composition. Moreover, net primary production (NPP) of young forest increased more rapidly with biomass than the middle-aged and mature forests. This relationship was also influenced by forest management. Natural L. gmelinii forests in Mts . Daxinganling decreased their NPP when the biomass was higher than 100-110 ton ha(-1) , while NPP still increased when the biomass reached to 168 ton ha(-1) in plantation. In a scale of small region, biomass and productivity were mainly regulated by tree age and site condition. The accompany species may indicate the productivity. However, in a large scale, they were mainly determined by latitude dependent climatic condition. The productivity from shrub layer and grass layers were positively correlated with NPP. Moreover, NPP (including these two layers) decreased more moderately with latitude than only tree productivity did. This finding indicates that shrub and grass layers may contribute more to NPP in the larch forests in high latitude region. Furthermore, root/shoot ratio in biomass exponentially increased with latitude, indicating that biomass allocated more to underground in less productive environment in high latitude region in Siberia. Finally, inter-species comparisons indicate that larch forests in Northeast China are expected to be a carbon sink by their higher NPP.

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