The relationship between net productivity and stand age, site index, stand density of Pinus tabulaeformis in north of Hebei province, China

Forest Energy fixes solar energy by photosynthesis of trees. Based on survey on Pinus tabulaeformis standard plots, the guiding curve model of tree height with stand age was established to calculate site index of each standard plot; the relationship model of plant biomass and tree height, diameter was established to calculate stand biomass; the relationship model between stand biomass and stand age, site index, stand density was established, and the relationship model between stand net productivity and stand age, site index, stand density was derived from it. The paper provided a theoretical basis to improve the level of forest management to fix maximum solar efficiency.