Determining suitable selection cutting intensities based on long-term observations on aboveground forest carbon, growth, and stand structure in Changbai Mountain, Northeast China

Abstract

We studied the effects of different cutting intensities (0%, 5–10%, 15%, and 20% basal area removal) on stand growth, structure, and net carbon storage in spruce–fir (Picea jezoensis (Sieb. et Zucc.) Carr.–Abies nephrolepis (Trautv.) Maxim.) and broadleaf mixed forests on Changbai Mountain (Northeast China) over 19 years. At this site, inventory-based low-intensity selection cutting was used to maintain a continuous forest canopy. After two cutting events, results showed significant differences in growth, structure, and carbon storage among cutting intensities. When increasing cutting intensity, the growth rate of average diameter, basal area, and volume significantly increased, with the highest increment rates found in the plots with 20% basal area removal. Tree diameters for all plots showed a roughly inverse J-shaped distribution before cutting and a left-skewed unimodal distribution after two cuttings. Volume ratio (the relative amount of volume contained in different diameter classes) for small (6–14 cm), medium (14–26 cm), large (26–36 cm), and very large (>38 cm) diameters remained unchanged in the plots with 5 and 10% basal area removal, but the volume ratio of large and very large diameters increased in the plots with 15 and 20% basal area removal, reaching approximately a 1:2:3:4 ratio in the plots with 20% basal area removal after two selection cuttings. Net carbon storage increased when increasing cutting intensity, reaching maximum storage in the plots with 20% basal area removal (cutting intensity and net C storage increase: 0%, 7.21 Mg C ha⁻¹, 5–10%: 11.68 Mg C ha⁻¹, 15%: 21.41 Mg C ha⁻¹, 20%: 26.47 Mg C ha⁻¹). Therefore, our results show the potential of low-intensity selection cutting to meet demands of both timber production and maintenance of forest cover for biodiversity values.

Keywords:

• close-to-nature forestry
• continuous-canopy forestry
• long-term research
• Manchurian mixed forests
• net carbon storage
• selection cutting
• spruce–fir forests
• uneven-aged management

Acknowledgments

The authors declare that they have no conflict of interests. Great thanks are extended to Mr. Yan Gao, Mr. Qixiang Feng, Mr. Dongning Zhao, Mr. Bin Wang and all Jingouling forest farmers for their help in maintaining the permanent subplots and taking part in the field measurement in Wangqing Forestry Bureau, Jilin Province. We would also like to thank all anonymous reviewers.

Funding

This study was funded by the 948 Project of State Forestry Administration [grant number 2013-4-66], Forestry Public Welfare Industry Research Item [grant numbers 200804027 and 201104006] and Key Projects in the National Science and Technology Pillar Program during the Twelfth Five-year Plan Period [grant number 2012BAD22B02-3]. This study also has received the support from the Chinese Academy of Sciences Strategic Project [grant number XDA05060101].

Additional information

Funding

Funding: This study was funded by the 948 Project of State Forestry Administration [grant number 2013-4-66], Forestry Public Welfare Industry Research Item [grant numbers 200804027 and 201104006] and Key Projects in the National Science and Technology Pillar Program during the Twelfth Five-year Plan Period [grant number 2012BAD22B02-3]. This study also has received the support from the Chinese Academy of Sciences Strategic Project [grant number XDA05060101].