Age-Dependent Changes in Soil Respiration and Associated Parameters in Siberian Permafrost Larch Stands Affected by Wildfire

The observed high spatial variation in soil respiration (SR) and associated parameters emphasized the importance of SR heterogeneity at high latitudes and the involvement of many factors in its regulation, especially within fire-affected areas. The problem of estimating CO2 emissions during post-fire recovery in high-latitude ecosystems addresses the mutual influence of wildfires and climate change on the C cycle. Despite its importance, especially in permafrost regions because of their vulnerability, the mutual influence of these factors on CO2 dynamics has rarely been studied. Thus, we aimed to understand the dynamics of soil respiration (SR) in wildfire-affected larch recovery successions. We analyzed 16-year data (1995-2010) on SR and associated soil, biological, and environmental parameters obtained during several field studies in larch stands of different ages (0-276 years) in the Krasnoyarsk region (Russia). We observed a high variation in SR and related parameters among the study sites. SR varied from 1.77 +/- 1.18 (mean +/- SD) mu mol CO2 m(-2) s(-1) in the 0-10-year-old group to 5.18 +/- 2.70 mu mol CO2 m(-2) s(-1) in the 150-276-year-old group. We found a significant increasing trend in SR in the 88-141-year old group during the study period, which was related to the significant decrease in soil water content due to the shortage of precipitation during the growing season. We observed a high spatial variation in SR, which was primarily regulated by biological and environmental factors. Different parameters were the main contributors to SR in each group, an SR was significantly affected by the inter-relationships between the studied parameters. The obtained results can be incorporated into the existing SR databases, which can allow their use in the construction and validation of C transport models as well as in monitoring global fluctuations in the C cycle in response to climate change.