Radial Growth-Climate Relationship Varies with Spatial Distribution of Schima superba Stands in Southeast China's Subtropical Forests

To understand the impact of climate change on the tree radial growth in Southeast China's subtropical evergreen broadleaved forest, comparative research on the radial growth-climate associations of Schima superba was conducted. This dominant evergreen broadleaved tree species was examined at both its southern and northern distribution margins through dendroclimatology. The results showed that the radial growth of S. superba stands at a high elevation in the southern margin and stands in the northern margin were positively correlated with springtime temperatures, mostly in April (e.g., mean temperature: r = 0.630, p < 0.05) and May (e.g., maximum temperature: r = 0.335, p < 0.05), respectively. Meanwhile, the temperature in the late rainy season had a significant negative effect on the radial growth of S. superba stands in the southern margin, including high-elevation stands (e.g., the mean temperature in previous and current September: r = -0.437 and -0.383, p < 0.05) and low-elevation stands (e.g., the mean temperature in previous August and October: r = -0.577 and -0.348, p < 0.05). It was shown that temperature was the key climatic factor affecting the radial growth of S. superba, and the response of radial growth to temperature had obvious spatial differences. The findings indicate that the radial growth of S. superba stands in warm growth environments will be negatively impacted by future climate warming. On the contrary, the radial growth of S. superba stands growing in relatively cold growth environments may benefit from warmer spring. The results enhance the understanding of tree growth responses to climate change in the subtropical forests of China.