eng Science and Education Publishing Applied Ecology and Environmental Sciences 2328-3920 2018-11-05 6 4 109 117 10.12691/aees-6-4-2 AEES2018642 article Dongsheng Chen 1 Xiaomei Sun 1 Shougong Zhang larch_rif@163.com 1 Research Institute of Forestry, Chinese Academy of Forestry, Key Lab for Forest Tree Breeding and Cultivation of State Forestry Administration, Beijing, 100091, P. R. China This study was performed in 22 unthinned Larix olgensis plantations in northeast . Data were collected on 95 sample trees of different canopy positions and the diameter at breast height (d1.3) ranged from to . The individual tree models for the prediction of vertical distribution of live crown, branch and needle biomass were built. Our study showed that the crown, branch and needle biomass distributions were most in the location of 60% crown length. These results were also parallel to previous crown studies. The cumulative relative biomass of live crown, branch and needle were fitted by the sigmoid shape curve and the fitting results were quite well. Meanwhile, we developed the crown ratio and width models. Tree height was the most important predictor for crown ratio model. A negative competition factor, ccf and bas which reflected the effect of suppression on a tree, reduced the crown ratio estimates. The height-diameter ratio was a significant predictor. The higher the height-diameter ratio, the higher crown ratio is. Diameter at breast height is the strongest predictor in crown width model. The models can be used for the planning of harvesting operations, for the selection of feasible harvesting methods, and for the estimation of nutrient removals of different harvesting practices. http://pubs.sciepub.com/aees/6/4/2/aees-6-4-2.pdf Larix olgensis plantations crown ratio crown width crown biomass