The modulus of elasticity of hybrid larch predicted by density, rings per centimeter, and age

摘要

A total of 492 specimens from eighteen trees representing fast-growth larch (Larix eurolepis [L. marschlinsii]) were studied. The mean values of the modulus of elasticity (MOE), density, age, and rings per centimeter were determined for each. Mathematical models were developed to predict the MOE from the other parameters. Linear models were first presented showing the dependence of MOE on each of the three parameters, density, age, and rings per centimeter. A multivariate linear regression model was then developed for MOE as a function of all three parameters. The correlation coefficient of this model was 0.66, an improvement over each of the models for which each parameter was taken individually. A prediction of MOE by visual means alone, i.e., using only age and rings per centimeter in a linear model, is also presented. The correlation coefficient of this model was 0.58, which is superior to any of the parameters taken individually. In order to develop a model useful for extrapolation beyond the range of test data, a nonlinear model is presented. The parameters of this nonlinear model can easily be interpreted in terms of (1) the maximum attainable stiffness, (2) the ring age for maximum MOE growth rate vs. age, and (3) the shape parameter ofthe model. It was found that the nonlinear model matched the data well and incorporated the realistic conditions of zero MOE at zero ring age and a limit on the maximum attainable MOE.