Journal of Geographical Sciences ›› 2019, Vol. 29 ›› Issue (7): 1179-1192.doi: 10.1007/s11442-019-1652-8

• Orginal Article • Previous Articles     Next Articles

Moisture content variations in soil and plant of post-fire regenerating forests in central Yunnan Plateau, Southwest China

Lifang CHEN1(), Qun DOU2, Zhiming ZHANG3, Zehao SHEN1,*()   

  1. 1. Institute of Ecology, College of Urban and Environmental Science, the MOE Laboratory of Earth Surface Processes, Peking University, Beijing 100871, China
    2. Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
    3. College of Ecology and Environment, Yunnan University, Kunming 650504, China
  • Received:2018-05-10 Accepted:2019-01-22 Online:2019-07-25 Published:2019-07-25
  • Contact: Zehao SHEN E-mail:chenlf0915@pku.edu.cn;shzh@pku.edu.cn
  • About author:

    Author: Chen Lifang, graduate student of landscape ecology. E-mail: chenlf0915@pku.edu.cn

  • Supported by:
    National Natural Science Foundation of China, No.41371190

Abstract:

Plant moisture content (PMC) is used as an indicator of forest flammability, which is assumed to be affected by climate drought. However, the fire-induced drought stress on PMC and its spatial and temporal variations are unclear. Based on a parallel monitoring experiment from 2014 to 2015, this study compared the PMCs and soil moisture contents (SMC) at five post-fire sites in central Yunnan Plateau, Southwest China. The number of years since last fire (YSF), season, topographic position, plant species and tissue type (leaf and branch) were selected as causal factors of the variations in PMC and SMC. A whole year parallel monitoring and sampling in the post-fire communities of 1, 2, 5, 11 and 30 YSF indicated that drought stress in surface soils was the strongest in spring within the first 5 years after burning, and the SMC was regulated by topography, with 64.6% variation in soil moisture accounted for by YSF (25.7%), slope position (22.1%) and season (10.8%). The temporal variations of PMC and SMC differed at both interannual and seasonal scales, but the patterns were consistent across topographic positions. PMC differed significantly between leaves and branches, and among three growth-forms. The mean PMC was lower in broad-leaved evergreen species and higher in conifer species. Season and soil temperature were the primary determinants of PMC, accounting for 19.1% and 8.3% of variation in PMC, respectively. This indicated phenology-related growth rather than drought stress in soil as the primary driver of seasonal changes in PMC. The significant variations of PMC among growth forms and species revealed that seasonal soil temperature change and dominant species in forest communities are useful indicators of fire risk assessment in this region.

Key words: plant moisture content, soil moisture content, topography, season, soil temperature, year since last fire, drought stress