Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6537262 | Agricultural and Forest Meteorology | 2015 | 10 Pages |
Abstract
Understanding soil respiration (Rs) response to thinning is an important component of our understanding of belowground carbon (C) dynamics and evaluating effects of forest management on C cycling. Therefore, we partitioned Rs into heterotrophic respiration (Rh) and autotrophic respiration (Ra) using trenched plots in a 20 year-old Pinus tabulaeformis plantation, subjected to varying thinning intensities, in Shanxi Province, China. Soil respiration was measured using an infrared gas exchange analyzer in untrenched and trenched plots. Rates of soil respiration were measured twice a month from May to October in 2011 and 2012, while soil temperature and moisture were obtained using temperature and moisture probes and data loggers. Rs was measured in untrenched plots and Rh in trenched plots. Mean Rs and Rh values were significantly greater in stands subjected to heavy thinning (HT) (Rs = 2.79 μmol CO2 mâ2 sâ1, Rh = 2.24 μmol CO2 mâ2 sâ1) than in the control (CK) (Rs = 2.29 μmol CO2 mâ2 sâ1, Rh = 1.81 μmol CO2 mâ2 sâ1) and low thinned stand (LT) (Rs = 2.48 μmol CO2 mâ2 sâ1, Rh = 1.80 μmol CO2 mâ2 sâ1). The mean Ra was greater in the thinned stands (Ra = 0.69, 0.58, 0.55 μmol CO2 mâ2 sâ1 in LT, moderate thinned stand (MT) and HT) than CK (Ra = 0.48 μmol CO2 mâ2 sâ1), possibly the result of increased productivity and root growth in thinned stands. The relative proportion of Rh to Rs averaged 71.6-79.7% over the four thinned stands. Temperature sensitivity (Q10) values of Rh ranged from 2.16 to 2.75 in the various thinning intensities, with the highest Q10 value in the control stand. Temperature sensitivity of Ra was also affected by thinning ranging from 1.34 to 1.84. The model with the best fitted temperature and moisture factors explained 66.7-77.3% of the variation in Rh and 30.2-46.4% in Ra among the four thinned stands during two growing seasons.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Atmospheric Science
Authors
Xiaoqin Cheng, Fengfeng Kang, Hairong Han, Hongwen Liu, Yanlei Zhang,