Abstract: To accelerate the genetic improvement process for Japanese larch (Larix kaempferi), thefuture net worth (FNW) model used for early selection is established in this paper.According to the calculation of residual squares sum and nonlinear regression correlation indices, the squares root tatio of genetic heritability g(x), and the juvenile-mature correlation coefficients r(x) with relative ages can better fit the quadratic function.If g(x)=1and k=0.75, selection should be made at age 6 and 11 respectively for tree height and itsincrement, and to predict the volume at mature stage with the indicators of tree heightand its increment, selection should be made at age 9 to 10.If g(x) and r(x) are quadraticfunctions, and interest rate (IR) is 0.05, the optimum selection ages for tree height andits increment should be 11-12 and 9-10 years respectively, and 5-7 year for the volume, using tree height as predictor.The result shows that the determination of optimumselection ages by applying FNW model is influenced by different rotation ages, interestrates and other economic factors.The efficiency of early selection for Larix haempferi,the influence of basic parameters on FNWmodel and the convergence range of optimumselection ages are also discussed in this paper.

Key words: Larix kaempferi, Heritability, Juvenile-mature correlation, Early selection, Future net worth