Abstract:

【Objective】 The stand net primary productivity (NPP) of the major forest types in Jiangxi Province was estimated based on the National Forest Inventory (NFI) data of 2011 and 2016 to provide a basis for the scientific management of forest resources. 【Method】 Based on the NFI data on Jiangxi Province in 2011 and 2016, at the sample tree level, individual tree biomass, and its growth and dry caustic consumption was calculated using a biomass regression individual tree model, then details were accumulated to the plot level and enlarged to the overall level of arbor layer. Then, the biomass at the shrub and herb layers were estimated based on the biomass at the arbor layer. Finally, the NPP of different forest types was calculated by combining the data estimated at the arbor, shrub and herb layers. 【Result】 Based on the model of individual tree-level biomass, with a comprehensive consideration of the effect of the arbor, shrub and herb layers, the NPP of the major forest types in Jiangxi Province was estimated from the NFI-repositioned sample tree level. The highest NPP was for mixed broad-leaved forest, followed by mixed coniferous and broad-leaved forest and then coniferous and single broad-leaved forest. The results showed that the average stand NPP in Jiangxi Province was 7.28 t/(hm²·a) during the interval, with mixed broad-leaved forest having the maximum NPP [11.26 t/(hm²·a)],mixed coniferous and broad-leaved forest having the second NPP[7.63 t/(hm²·a)],but coniferous and single broad-leaved forest lower than the average NPP. 【Conclusion】 This study explored a NPP estimation schema in the framework of national standards and provides a reference for more accurate and objective calculation of NPP based on major forest types in a large range of area by adopting unified standards nationwide.

Key words: national forest inventory, biomass, net primary productivity (NPP), modelling method, forest litters, mortality, Jiangxi Province