Factors affecting spatial variation of annual apparent Q₁₀ of soil respiration in two warm temperate forests

PLoS One. 2013 May 22;8(5):e64167. doi: 10.1371/journal.pone.0064167. Print 2013.

Abstract

A range of factors has been identified that affect the temperature sensitivity (Q₁₀ values) of the soil-to-atmosphere CO₂ flux. However, the factors influencing the spatial distribution of Q₁₀ values within warm temperate forests are poorly understood. In this study, we examined the spatial variation of Q₁₀ values and its controlling factors in both a naturally regenerated oak forest (OF) and a pine plantation (PP). Q₁₀ values were determined based on monthly soil respiration (R(S)) measurements at 35 subplots for each stand from Oct. 2008 to Oct. 2009. Large spatial variation of Q₁₀ values was found in both OF and PP, with their respective ranges from 1.7 to 5.12 and from 2.3 to 6.21. In PP, fine root biomass (FR) (R = 0.50, P = 0.002), non-capillary porosity (NCP) (R = 0.37, P = 0.03), and the coefficients of variation of soil temperature at 5 cm depth (CV of T₅) (R = -0.43, P = 0.01) well explained the spatial variance of Q₁₀. In OF, carbon pool lability reflected by light fractionation method (LLFOC ) well explained the spatial variance of Q₁₀ (R = -0.35, P = 0.04). Regardless of forest type, LLFOC and FR correlation with the Q₁₀ values were significant and marginally significant, respectively; suggesting a positive relationship between substrate availability and apparent Q₁₀ values. Parameters related to gas diffusion, such as average soil water content (SWC) and NCP, negatively or positively explained the spatial variance of Q₁₀ values. Additionally, we observed significantly higher apparent Q₁₀ values in PP compared to OF, which might be partly attributed to the difference in soil moisture condition and diffusion ability, rather than different substrate availabilities between forests. Our results suggested that both soil chemical and physical characters contributed to the observed large Q₁₀ value variation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomass
  • Carbon Dioxide / metabolism
  • Climate*
  • Soil*
  • Trees*

Substances

  • Soil
  • Carbon Dioxide

Grants and funding

This study was jointly funded by the Ministry of Finance (numbers 200804001 and 201104006), China’s National Natural Science Foundation (30590383; 31200370), the Ministry of Science and Technology (2011CB403205, 2008DFA32070, 2006BAD03A04), and CFERN & GENE Award Funds on Ecological Paper. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.