Objective This paper analyzes the effects of genetic and climate changes on wood microfibril angle of Larix kaempferi and establishes predictive models of wood microfibril angle, it can be used to predict the quality of harvested wood at the end, intending to improve the breeding efficiency of genetic materials and promote targeted cultivation of target species.

Method 20 clones of Larix kaempferi were selected as the research objects. The microfibril angle of 12 consecutive annual rings of the forest aged from 4 to 15 years was measured by wood core sampling, the relationship between microfibril angle and tree age and ring width was analyzed. A basic prediction model for microfibril angle was established, and the correlation between microfibril angle and climate variables was analyzed, a mixed effect model was used to establish a prediction model for microfibril angle of Larix kaempferi, which includes genetic effects and climate variables.

Result The microfibril angle decreased with the increase of tree age, while increased with the increase of width of annual ring, the change of microfibril angle was obviously different among varied clones. The basic model containing tree age and ring width had an R² of 0.43 and RMSE of 4.391. After adding average annual precipitation and winter average precipitation, the model had an R² of 0.54 and RMSE of 4.039. The prediction model of microfibril angle with genetic effects, average annual precipitation, and winter average precipitation was established using a mixed model, with R² of 0.81 and RMSE of 3.061.

Conclusion An increase in average annual precipitation and winter average precipitation will increase the microfibril angle of Larix kaempferi, and two climate variables explain 11% of the microfibril angle variation. Genetic effects have a greater impact on microfibril angle of Larix kaempferi, accounting for 27% of microfibril angle variation. Moreover, the microfibril angles of different clones exhibite different responses to climate changes. Clone I6-7-075, I8-4-30 and J28-6 are more passivity towards climate change, making them more ecologically adaptable and suitable for further application in suitable areas of Larix kaempferi.