Microbial biomass and enzymatic responses to temperate oak and larch forest thinning: Influential factors for the site-specific changes

Seongjun Kim; Guanlin Li; Seung Hyun Han; Choonsig Kim; Sang-Tae Lee; Yowhan Son

doi:10.1016/j.scitotenv.2018.10.153

Microbial biomass and enzymatic responses to temperate oak and larch forest thinning: Influential factors for the site-specific changes

Sci Total Environ. 2019 Feb 15;651(Pt 2):2068-2079. doi: 10.1016/j.scitotenv.2018.10.153. Epub 2018 Oct 11.

Authors

Seongjun Kim¹, Guanlin Li², Seung Hyun Han³, Choonsig Kim⁴, Sang-Tae Lee⁵, Yowhan Son⁶

Affiliations

¹ Department of Environmental Science and Ecological Engineering, Graduate School, Korea University, Seoul 02841, South Korea; Institute of Life Science and Natural Resources, Korea University, Seoul 02841, South Korea.
² Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
³ Department of Environmental Science and Ecological Engineering, Graduate School, Korea University, Seoul 02841, South Korea.
⁴ Department of Forest Resources, Gyeongnam National University of Science and Technology, Jinju 52725, South Korea.
⁵ Forest Technology and Management Research Center, National Institute of Forest Science, Pocheon 11186, South Korea.
⁶ Department of Environmental Science and Ecological Engineering, Graduate School, Korea University, Seoul 02841, South Korea. Electronic address: yson@korea.ac.kr.

PMID: 30321728
DOI: 10.1016/j.scitotenv.2018.10.153

Abstract

Microbial biomass and enzyme activity are essential for ecosystem function in managed forests; however, uncertainty remains because microbial biomass and enzymatic responses to thinning highly differ with case studies. This study addressed the drivers for the site-specific responses of microbial biomass and enzyme activity to thinning. Study sites included two oak and three larch forests; each had un-thinned control, intermediate thinning (15-23% basal area reduction), and heavy thinning treatments (30-44% basal area reduction). Soil properties (temperature, water content, pH, total and inorganic nitrogen, and total carbon/nitrogen ratio), microbial biomass, enzyme (β-glucosidase, N-acetylglucosaminidase, leucyl aminopeptidase, acid phosphatase, and phenol oxidase) activity, and soil carbon storage were determined 6 years after thinning. Compared to the control, microbial biomass carbon and nitrogen were higher under the intermediate and the heavy thinning by 13.9 and 24.4% and 11.5 and 29.9% at one oak forests, respectively, and higher under the intermediate thinning by 53.7 and 70.7% at one larch forests. There were the post-thinning changes in leucyl aminopeptidase activity by -46.9% and by 150.0-210.0% at an oak and larch forest, respectively, acid phosphatase activity by 60.0% at one oak forest, and phenol oxidase activity by 355.0% at one oak forest. The effect sizes of thinning for soil properties explained 94% and 77% of variance of the effect sizes for microbial biomass and enzyme activity. Especially, the effect sizes for soil water content, NH₄⁺, total carbon/nitrogen ratio, and temperature were the most influential. Furthermore, the effect size for soil carbon storage was parabolically related to the effect size for microbial biomass carbon (R² = 0.66). These findings highlight that inconsistent thinning effects on soil properties varied microbial biomass and enzymatic responses to thinning, which differentiated the change in soil carbon storage across sites. Future studies should consider such inconsistencies when examining the effects of forest management.

Keywords: Enzyme activity; Forest management; Response ratio; Soil carbon storage; Thinning intensity.

MeSH terms

Forestry*
Forests*
Larix / growth & development
Microbiota*
Quercus / growth & development
Republic of Korea
Soil / chemistry*
Soil Microbiology*

Substances

Soil