阔叶红松林林木与林分生长对采伐干扰的响应

提升森林质量、修复生态功能是东北阔叶红松林生态修复的核心,而阐明林木与林分生长对采伐干扰的响应机理是其中的关键。森林对采伐干扰的响应会受到空间尺度、时间尺度以及干扰程度等因素的综合影响。以往的研究侧重于比较不同采伐处理下林木生长的相对大小,而忽视了不同恢复时间下,林木和林分生长随干扰程度的变化。以吉林蛟河阔叶红松林采伐样地为对象,基于连续四次样地调查数据(2011、2013、2015、2018年),分别探讨了林木和林分生长在不同恢复阶段对不同程度采伐干扰的响应,并通过构建分段模型确定采伐干扰阈值。结果显示:林木和林分生长对采伐干扰的响应并不一致,采伐促进了林木生长,并且林木生长量随采伐强度的升高而升高;采伐降低了林分生产力,林分生产力随采伐强度的升高而降低。林木和林分生长对采伐干扰的响应存在时滞效应:林木和林分生长在采伐后两年内并无显著变化,而在采伐三年后才发生明显变化。此外,分段模型的结果显示:当保留木断面积为21.6 m²/hm²时,林分生产力最高,表明通过密度调整使阔叶红松林胸高断面积维持在21.6 m²/hm²附近,可使林分处于较高的生产力水平、促进森林恢复。研究结果能够为制定科学的阔叶红松林生态修复策略提供技术支撑。

Responses of tree growth and stand productivity to harvesting disturbance in Korean pine-broadleaved forests

Restoring forest quality and ecosystem functions is one of the core goals of sustainable forest management. Elucidating the response mechanism of tree and stand growth to harvesting disturbance can provide important guidance. Previous studies preferred to compare the dissimilarity of tree or stand growth under different harvesting treatments, but ignored the differential response of trees to disturbance intensity under different recovery times. This study was conducted in the Korean pine-broadleaved forests in Jiaohe, Jilin province. Based on the observational data collected in 2011, 2013, 2015, and 2018, we compared the effects of different harvesting intensities and recovery times on tree growth and stand productivity. We evaluated the harvesting threshold of forest productivity using linear and segmental models. The results showed that forest harvesting had significant effects on trees growth and stand productivity. Harvesting promoted tree growth, but reduced stand productivity. Specifically, within two years after harvesting, there was no significant difference in tree and stand growth, while three years after harvesting, tree growth increased significantly, indicating a time lag effect of forest harvesting. In addition, the results based on the segmental models showed that stand productivity was the highest when the remaining basal area was 21.6 m²/hm². Therefore, from the perspective of sustainable management, 21.6 m²/hm² was the most favorable stand density for forest restoration. The results provide technical guidance for the management and restoration of Korean pine-broadleaved forests.