Estimation of annual soil respiration rate in a larch forest in Central Siberia.

Soil respiration is an important component process of carbon cycle in terrestrial ecosystems. The forested area of the continuous permafrost zone of Central and Northeastern Siberia exceeds that of boreal forests in other regions of the world. However, soil respiration has rarely been studied in Siberia. We conducted soil respiration rate (SR) measurement during the three growing seasons (2005–2007) and in a mid-winter by using a closed-chamber technique in a typical mature Larix gmelinii forest in Central Siberia. We examined micro-scale variations of SR by comparing the three dominant types of forest floor vegetation (lichen and mosses); patches of Cladina stellaris , Pleurozium schreberi , and Aulacomnium palustre . The daily mean SR at each period differed among the types: the values throughout the observation period (mg C/m 2 /h) was the highest in Pleurozium (21–110), followed by Cladina (17–85) and Aulacomnium (9–68). The SR was positively correlated with soil temperature. The lowest SR in the Aulacomnium patch was related to higher soil moisture and lower soil temperature than the other two patches. Estimated annual SR was apparently smaller in the larch forest of Siberia than those reported for any other boreal forests.