Abstract: We studied the dynamic of annual carbon emissions of mortality trees, the carbon storage of ingrowth trees, the net increment of carbon storage, and the change trend of carbon storage along with site quality and stand density for natural larch(Larix gmelinii) forestwith the data of 602 permanent sample plots(PSPs) from forest resources continues inventory of four periods between 1990-2010 in Daxing’an Mountains. The emissions of carbon for all age groups were 0.133 7-0.484 1 t·hm^-2·a, and it increased with the increasing of age group. The carbon storage of ingrowth trees is larger(0.128 2 t·hm^-2·a) in young stand, it is smaller(0.04 t·hm^-2·a) in near-mature stand and there are not significant for other age group. The net increment of carbon storage is inversely proportional with the age group, and they are 1.374 9, 0.982 1, 0.649 9, 0.538 1 and 0.240 7 t·hm^-2·a for young, middle-aged, near-mature, mature, and over-mature stand, respectively. The emissions of carbon for all age group are positive correlated with stand density under same site quality. The carbon storage of ingrowth trees for young, middle-aged and mature stand decrease with increasing of stand density, and it’s not significant for near-mature stand and over-mature stand. The net increment of carbon storage is the maximum with middle stand density for all age groups except young aged stand. Under the same stand density, the emissions of carbon of all age groups(except near-mature stand and mature stand) are inversely proportional with site quality. For all age groups(except mature stand), the better the site quality is, the smaller the carbon storage for ingrowth trees is. Under the similar stand density, the better the site quality is, the greater the net increment of carbon storage is.

Key words: Daxing’an Mountains, natural larch forests, carbon emissions, dynamic change, the increment of carbon storage