Abstract:The biomass,productivity of the multi-layer forests for Pinus massoniana and Cinnamomum cassia under different light treatments was studied by the methods of sampling plot harvesting method and allometric dimension analysis in Cenxi City.The results were as follows.(1)Among different treatments,the biomasses of litter layer increased while the shrub and herb layer decreased with the shade density increasing.The stand biomass,productivities and total biomass in multi-layer forests are far more than that in the single-layer pine forest during the management period.(2)The net productions of stand in multi-layer forests were more than that in the single-layer pine forest and the stand structure with 0.5～0.7 shade density of pine those multi-layer forests was helpful to get light resource.Particularly,the multi-layer model with 0.5 shade density in upper layer and 781 trees/hm2 of pine and 5 952 trees/hm2 of cinnamon were considered the desired pattern on economic and ecological benefits that showed the distinct stratification with the highest total biomass (167.64 t/hm2),biomass of tree layer (160.549 t/hm2 ) and net productivity ［9.146 t/(hm2·a)］ were 14.9%,18.5% and 68.7% higher than that the single-layer pine forest respectively.From the results,adjusting light resource affected on the distribution of total biomass significantly and also had major impact on allocation of organ biomass.The multi-layer forest improved the proportion of tree biomass in the total biomass which illustrated its stronger ability to gain environment resources,consequently,to improve forest stability.