The boreal larch forest of Eurasia is a widespread forest ecosystem and plays an important role in the carbon budget of boreal forests. However, few carbon budgets exist for these forests, and the effects of wildfire, the dominant natural disturbance in this region, on carbon budget are poorly understood. The objective of this study was to quantify the effects of fire on the carbon distribution and net primary production (NPP) for three major Dahurian larch (Larix gmelinii Rupr.) forest ecosystems in Tahe, Daxing'anling, northeastern China: Larix gmelinii-Ledum palustre, Larix gmelinii–grass, and Larix gmelinii–Rhododendron dahurica forests. The experimental design included primary forests (not burned), and lightly and heavily burned forests from the large 1987 wildfire. We measured carbon distribution and aboveground NPP, and estimated fine root production from literature values.

Forest type and fire intensity influenced carbon content and relative distribution. Total ecosystem carbon content for the primary forests was greatest for Larix-ledum forests (251.4 t C ha-1 ) and smallest for Larix-grass forests (123.8 t C ha-1). Larix-ledum forests contained the smallest percentage of the total ecosystem carbon content in the vegetation (13.5%), while Larix-rhododendron contained the largest percentage of the total ecosystem carbon content in the vegetation (62%). High-intensity fire tended to transfer carbon from vegetation to soil. Total NPP did not differ between the lightly burned and unburned stands, and averaged 1.01, 1.58, and 1.29 t C ha-1 yr-1 for Larix-ledum, Larix-grass, and Larix-rhododendron lightly burned stands, respectively. Aboveground net primary production (ANPP) of heavily burned stands was 92 to 95% less than unburned and lightly burned stands. The estimated carbon loss during the 1987 fire showed substantial variability depending on assumed relative distribution of forest types and fire intensity of the burned area; estimates ranged from –13 to +132 t C ha-1, and averaged 4.5 times greater than published estimates for these same forests. This study illustrates the need to distinguish among the different Larix forests for developing general carbon budgets and the need to directly measure carbon losses from wildfire.

Publication
Wang, C.K., S.T. Gower, Y.H. Wang, H.X. Zhao, P. Yan, and B. Bond-Lamberty. 2000. Influence of fire on carbon content and distribution of boreal Larix gmelinii forests in northeastern China. Global Change Biology.