2.4. Temporal change in population structures
We selected the age classes 3–7 (DBH \(\geq\) 2.5 cm) with available data both in 2013 and 2023 to compare the temporal changes in population numbers in each age class. We also compared the overall difference in basal areas, abundances, and frequencies by aggregating data from these age classes. Frequency was calculated as the proportion of 10 m × 10 m plots with Q. chungii presence.