Abstract: To search the effects of different fertilization prescriptions on woody traits of Betula platyphylla, we chose four group B.platyphylla, fertilized by nitrogen, potash, phosphatate and total nutrient elements fertilizer, respectively, for three years’ treatment. We observed the differences between four groups of B.platyphylla in terms of growth characteristics, the content of lignin and cellulose, wood density, microfibril angle, and fiber morphology changes. Two groups fertilized by nitrogen and total nutrient elements fertilizer had significant changes compared to the control group. Diameter at breast height of two groups were 1.6 and 1.9 times more than that of the control group, respectively; crown width were 1.4 times and 1.5 times more than that in the control group, respectively; cellulose contents increased by 8.7% and 14.3% than that in the control group, respectively. In cross-sectional unit area, the number of catheters increased, the diameters of catheters decreased, length and width of fibers decreased significantly. However, lignin contents and aspect ratio of those two groups did not change significantly. In contract, the wood density of the group fertilized by phosphatate fertilizer had increase by 5% than that of the control group, and microfibril angle of the phosphatate fertilized group decreased by 5.4% than that of the control group. The results are that increasing nitrogen fertilizer reasonably can improve the paper performance of birch and the increasing phosphate fertilizer reasonably can improve the mechanical strength of birch.

Key words: Betula platyphylla, fertilization, cellulose, conduits, fiber morphology