Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (6): 642-655.DOI: 10.17521/cjpe.2021.0454

• Research Articles • Previous Articles     Next Articles

Responses of tree growth to harvesting intensity among forest strata and growth stages in a broadleaved Korean pine forest

WEI Long-Xin, GENG Yan(), CUI Ke-Da, QIAO Xue-Tao, YUE Qing-Min, FAN Chun-Yu, ZHANG Chun-Yu, ZHAO Xiu-Hai   

  1. Research Center of Forest Management Engineering of State Forestry and Grassland Administration, Beijing Forestry University, Beijing 100083, China
  • Received:2021-12-06 Accepted:2022-02-24 Online:2022-06-20 Published:2022-03-15
  • Contact: GENG Yan
  • Supported by:
    National Natural Science Foundation of China(32171521);National Natural Science Foundation of China(32001312)


Aims Harvesting is an important way to adjust stand structure. Trees in different forest strata have different responses to harvesting intensity. Traditionally, qualitative or simple quantitative methods (e.g., with equal distance of tree height) were used to identify the vertical layers of the forest, and the impact of harvesting on each layer were analyzed subsequently. However, these methods of specification ignore the differences in tree growth between different tree species and different developmental stages within the same layer.

Methods Four permanent plots were established in a broadleaved Korean pine forest in Jiaohe, Jilin Province, ranging in harvesting intensities from low (17.3% of basal area removed), medium (34.7%) to high (51.9%), together with an unharvested control plot. Tree growth rates were documented 2, 4 and 7 years after harvesting. According to the position of an individual tree in the forest layer, as well as its development stages, we aggregated all individuals into three cohorts: mature canopy trees (I), immature canopy trees (II), and understory species of any size (III). Tree diameter growth of each cohort were compared during different recovery periods.

Important findings The average relative growth rate (RGR) of diameter at breast height (DBH) for cohort II (0.033 cm·cm-1·a-1) was significantly higher than that of cohort I (0.016 cm·cm-1·a-1) and II (0.018 cm·cm-1·a-1). Overall, harvesting promoted the DBH growth of most canopy dominant tress (I and II). In particular, RGR of cohort II increased progressively with increasing harvesting intensity, while only the greatest harvesting intensity showed a significant positive effect on RGR of cohort I. In contrast, rare species showed weak responses to harvesting treatment. It should be noted that there was a response lag of tree growth to harvesting: no detectable difference in RGR was found between control and harvested plots within the first two years after harvesting, whereas the positive effect of harvesting on RGR began to appear 2-4 years after harvesting and continued during the subsequent monitoring period. The RGR of each cohort decreased with the increase of initial DBH. Moreover, the slopes of initial DBH-RGR relationship increased with harvesting intensity, suggesting that smaller trees benefited more from reduced competition. Our results may provide scientific basis for a more accurate monitoring of the post-harvesting forest dynamics, and would be helpful to future sustainable management of temperate mixed forests.

Key words: broadleaved Korean pine forest, harvesting intensity, relative growth rate, forest strata, tree size, recovery period