Abstract: A radar coherent scattering model for forest canopies based on fractal-generated trees and forest dynamics models is established.In order to obtain the position of scatterers,the fidelity of forest structure is simulated by two models: forest dynamics and fractal-generated trees model.Forest dynamics model,ZELIG,can get stand structural composition in some ages.A fractal-generated trees model,L-system,can simulate a 3D tree.Every scatterers are obtained by linking up ZELIG with L-system.Radar coherent scattering model simulates the information of radar backscattering by output of ZELIG and L-system.The prediction results of coherent model is validated by the JERS-1 SAR and Envisat ASAR data from the pure birch of Changqing test site in Daxing'anling.