Short-term effects of thinning on the development and communities of understory vegetation of Chinese fir plantations in Southeastern China

Xuelei Xu; Xinjie Wang; Yang Hu; Ping Wang; Sajjad Saeed; Yujun Sun

doi:10.7717/peerj.8536

Short-term effects of thinning on the development and communities of understory vegetation of Chinese fir plantations in Southeastern China

PeerJ. 2020 Feb 11:8:e8536. doi: 10.7717/peerj.8536. eCollection 2020.

Authors

Xuelei Xu¹, Xinjie Wang¹, Yang Hu¹, Ping Wang², Sajjad Saeed³, Yujun Sun¹

Affiliations

¹ State Forestry Administration Key Laboratory of Forest Resources & Environmental Management, College of Forestry, Beijing Forestry University, Beijing, China.
² College of Grassland Science, Beijing Forestry University, Beijing, China.
³ Department of Forestry & Wildlife Management, University of Haripur, Haripur, Pakistan.

Abstract

Background: High-density conditions are global issues that threaten the sustainable management of plantations throughout the world. Monocultures and untimely management practices have identically resulted in the simplex of community structures, decreases in biodiversity, and long-term productivity losses in plantations China. The most popular measure which is commonly used to address these issues is thinning, which potentially results in increases in the development of understory plants in plantations. However, there is limited information currently available regarding the community composition of understory vegetation and the associated environmental factors, which has limited the sustainable management of China's fir plantation ecosystems.

Method: In the present study, a thinning experiment was implemented which included a control check (CK: no thinning), as well as low intensity thinning (LIT: 20%), moderate intensity thinning (MIT: 33%), and high intensity thinning (HIT: 50%) in Chinese fir plantations located in the Southeastern China. During the investigation process, the understory vegetation examined three years after thinning measures were completed, in order to analyze the impacts of different thinning intensities on the growth and community composition of the understory plants. At the same time, the associated environmental factors in the fir plantations were also investigated.

Results: The species richness, total coverage, and biomass of the understory vegetation were observed to be apparently increased with increasing thinning intensity. In addition, it was found that the thinning measures had prominently influenced the soil nutrients. The community compositions of the understory vegetation were significantly different among the four thinning intensity levels, especially between the CK and the HIT. Furthermore, the development of the understory vegetation was found to be significantly correlated with the soil nutrient contents, and the community compositions of the understory vegetation were prominently driven by the tree densities, slope positions, and soil nutrient contents.

Keywords: Chinese fir plantations; Community composition; Thinning intensities; Understory vegetation diversity; Understory vegetation growth.

Grants and funding

This work was supported by the National Natural Science Foundation of China: Study on crown models for Larix olgensis based on tree growth (No. 31870620), the National Key Research & Development (R&D) Program of China: tending regeneration technique of spruce-fir forest (2017YFC050410101) and the Short-term International Student Program for Postgraduates of Forestry First-Class Discipline (2019XKJS0501). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.