Afforestation plays a critical role in ecosystem restoration and carbon sequestration. However, there continues to be insufficient knowledge about the long-term effects of different tree species on the forest soil in central subtropical China. In this study, five indigenous afforestation tree species commonly used in the region, including Bretschneidera sinensis, Liriodendron chinense, Schima superba, Phoebe bournei, and Cunninghamia lanceolata, were selected to explore their long-term effects on the forest soil. The soil’s physicochemical properties, organic carbon content, enzyme activity, and respiration were investigated. Our results revealed significant differences in the soil physicochemical properties, enzyme activity, organic carbon content, and soil respiration among the different tree species even with the same tree species types. Broad-leaved species, particularly L. chinense and P. bournei, exhibited superior soil physicochemical properties, higher amounts of organic carbon contents, enzyme activity, and soil respiration compared to coniferous species C. lanceolata. Notably, for the two studied evergreen tree species, P. bournei seemed to improve the forest soil quality more than S. superba. Hence, increasing the proportion of broad-leaved tree species may have a beneficial effect on the soil’s physicochemical properties and microecology. Furthermore, considering tree species’ compositions in afforestation will help to optimize soil quality and ecosystem health.

The subtropical region of China possesses abundant broad-leaf tree species resources; however, the anatomical properties and microstructure of the wood are still unclear, which restricts the processing and utilization of wood. In this study, 14 broad-leaf trees and four coniferous trees were selected. Wood anatomical indices and wood microanatomy were used to evaluate the wood properties using a comprehensive index method. The results have shown that Dalbergia assamica exhibited the highest wood basic density among the 14 broad-leaved tree species, accompanied by a significant fiber proportion and vessel lumen diameter but a small vessel proportion and a high number of wood rays. Conversely, Parakmeria lotungensis and Michelia chapensis had relatively low wood basic densities, rendering them less suitable as valuable broad-leaved wood sources. Altingia chinensis, Castanopsis kawakamii, and the remaining 11 tree species exhibited medium-level wood basic densities. The 14 broad-leaved tree species had medium-length fibers. Phoebe bournei, Dalbergia assamica, and Castanopsis kawakamii demonstrated relatively high fiber proportion. Altingia chinensis, Dalbergia assamica, and Castanopsis kawakamii exhibited a large number of wood rays, making their wood more susceptible to cracking, whereas other broad-leaved tree species possessed fewer wood rays. The findings have provided a scientific basis for the exploration of precious broad-leaved tree resources and wood use.

Tsoongiodendron odorum Chun is a large evergreen tree in the Magnoliaceae family and an ancient relict species represented by small wild populations. It has excellent material quality, high ornamental value, and scientific significance. However, due to the complicated natural reproduction and notable habitat destruction, its wild populations must be urgently conserved. We used genotyping-by-sequencing to examine 17 natural populations of T. odorum in China, the species’ primary habitat, to better understand the genetic diversity of this species and use its germplasm resources. T. odorum had a very low level of genetic diversity; its mean values for Ho, He, Pi, and PIC were 0.175, 0.123, 0.160, and 0.053, respectively. With an average within-population Fst of 0.023 and an inter-population gene flow Nm of 10.918, population genetic variation was primarily found within populations, demonstrating minute genetic divergence between populations. The 17 natural populations of T. odorum were divided into two major categories: the Fujian populations in eastern China and the Jiangxi, Guangdong, Hunan, and Guangxi populations in central and western China. Our research contributes to the understanding of T. odorum’s genetic diversity and organization and offers a theoretical framework for the species’ conservation, breeding, and selection.