Material, sample site and micro-environmental
A 20-hectare plot was selected in an evergreen broad-leaved forest
located in DHS National Nature Reserve (112°30ʹ 39″–112° 33ʹ 41″ E, 23°
09ʹ 21″–23° 11ʹ 30″ N). This forest is characterised by a south
subtropical monsoon climate. This choice plot was divided into 500 20×20
m smaller plots and one C. chinensis individual in each small
plot was selected randomly. We collected 308 individuals in recovering
stands and 73 individuals in native stands (Fig. 1a-b). From each
individual, 3–5 new completely spread leaves were collected and mixed
to extract DNA using the CTAB method. For individual variables, we
recorded diameter at breast height (DBH) and 14 environmental variables
including soil water content (SWC), soil bulk density (BD), soil pH
values, soil organic matter (SOM), available potassium (AK), available
phosphorus (AP), available nitrogen (AN), total nitrogen (TN), total
phosphorus (TP), total potassium (TK), altitude, aspect, slope, and
convexity as described by Chen et al . (2016). C. chinensisis a wind-pollinated plant, and seeds are dispersed by animals (Peng &
Xu, 2005). The general information about the soil and topography of the
two stands is given (Fig. 1c).