Leaf functional traits and correlations in three zonal forests in eastern China

To study the adaptation mechanisms of leaf traits to the environment, three typical forests (Shennongjia, Saihanba, Huzhong) along a latitudinal gradient in eastern China were used to analyze variations in leaf thickness, leaf area, specific leaf area, and leaf dry matter content, as well as their relationships between different life forms and attributes. Results showed that, with latitude increasing, leaf thickness decreased at first and then increased; leaf area decreased significantly, with the leaf area of Mt. Shennongjia found to be 2.3 times higher than that of Mt. Saihanba and 5.8 times higher than that of Mt. Huzhong; leaf dry matter content did not change significantly; and specific leaf area increased at first and then decreased. Leaf thickness was significantly negatively correlated with specific leaf area and significantly positively correlated with leaf dry matter content. Specific leaf area was significantly negatively correlated with leaf dry matter content. Forest type explained most of the variation in leaf thickness, leaf area, and specific leaf area, accounting for 75.99%, 80.23%, and 59.96% of the variation, respectively, whereas life form explained most of the variation in leaf dry matter content, explaining 86.79% of the variation. With increasing latitude, the correlation between specific leaf area and leaf dry matter content of different life forms did not change significantly, with the negative correlation remaining unchanged. Our study showed that both forest type and life form played an important role in regulating leaf trait variation. Thus, differences in leaf adaptability to the external environment can lead to differences in forest leaf traits in different climatic zones.