Abstract:Taking F. hodginsii of different ages as the research object, comparing the differences in the growth indexes and organ nutrients of F. hodginsii at different stages under the two stand models, and combining the changes in the nutrients of each organ with the growth of the forest age Trend, to clarify the correlation between the growth characteristics of F. hodginsii and nutrient content.The results showed that (1)with the increase of the forest age, the density of the two forest models decreased significantly but the total accumulation gradually increased, and the growth indicators of the different growth periods of F. hodginsii under the mixed model were better than those of pure forests of the same age;(2)The content of carbon (C) and nitrogen (N) elements in the leaves of F. hodginsii under the two forest management models showed an upward trend with the increase of forest age. The phosphorus (P) content was the highest at 15 years of age, and The content of potassium (K) was significantly higher than that of pure forest, and the potassium (K) content reached the peak at 21 years old, while the K content of mixed forest leaves was also lower than that of pure forest. This difference reached significant at 33 years old;(3)The N and K content of branches decreased with the increase of forest age. The content of K in branches of pure forest was higher than that of mixed forest, and the content of N in mixed forest was higher than that of pure forest. There was no significant difference in C content in the branches of the two forests of F. hodginsii, but the P content showed an opposite trend;(4)The trunk C content increased with the growth of the forest, the N content first decreased and then increased, the trunk P content decreased significantly with the increase of the forest age, and the P content of the mixed forest was lower than that of the pure forest, but the difference was not significant. The K content in the trunk of the pure forest was slightly higher than that of the mixed forest in the early growth period, but its content was significantly reduced in the middle and late growth period, and the K content in the mixed forest was significantly increased;(5)The C and N content of roots decreased with the increase of forest age, and the mixed benefit significantly reduced the C content of roots and increased its N content. The content of P and K varies greatly, and the mixing benefits will also promote the content of the two in F. hodginsii.