11institutetext:
Knowledge-based Systems and Document Processing Research Group
Faculty of Computer Science
Otto-von-Guericke-University Magdeburg
11email: katrin.krieger@ovgu.de
We established two permanent plots in the nature reserve to
survey the population of Q. chungii in 2013. One plot is 40 m ×
40 m located near Tangxia village, and the other is 20 m × 30 m located
at Fengshiling. We measured every tree with a DBH (diameter at breast
height) ≥ 2.5 cm within the plots in 2013.
To assess the temporal changes in population structures, we
re-surveyed the population in the two permanent plots in 2023. To obtain
a more complete structure of population, we measured all individuals,
including seedlings with a DBH \(<\ \)2.5 cm, within the
permanent plots. We established four additional 20 m × 20 m plots near
Tangxia village in the nature reserve to measure all individuals ofQ. chungii. Thus, in 2023, we surveyed the population structure
of Q. chungii in a total area of 3800 \(m^{2}\) with
dense distribution of the focal species.
2.3. Population age structure
We used the size structure of Q. chungii to represent its
age structure, as it is difficult to directly measure age from such a
rare and endangered tree species and size structures are commonly used
to infer population age structures of tree species (Harcombe
1987, Wei et al. 2020, Ta et al. 2021, Wu et al. 2021, Zhang et al.
2023). We separated the population into seven age classes based on the
estimated relationship between tree age and size from logged Q.
chungii in this nature reserve (Yang 2005) and previous
studies on the growth (Liu 2005) and population structures