The Effect Of Forest Fire On Carbon Budget In Daxing'an Mountains

The forest fire is one of the most important interference factors of the forest ecosystem in Daxing'an Mountains.The carbonaceous gases given off during the forest fire have influence on the air carbon balance and the global climate change.The estimation of the carbon emission and fixation is of theoretical and practical significance to quantize the effects of forest fire on carbon balance,and provide scientific basis to study the effect on global change of the forest ecosystem in high latitude area.On the basis of the consecutive forest resources inventory data and the forest fire data in Daxing'an Mountains,the carbon budget and the dynamic of the NPP following forest fires during 26 years were studied by the GIS.The results show there were 858 fires including 615 forest fires during the year 1980 to 2005 in Daxing'an Mountains.The areas of the forest fired in forest fire alarm,low-grade fire,medium-grade fire and serious-grade fire are respectively 117.87 hm~2,2 598.96 hm~2,7 950 hm~2 and 1 280 839.30 hm~2.The total biomass loss is 31.94～39.60 Tg in the forest fire during the year 1980 to 2005. There was 56%of the total about larix and 33%of the total about the brich.The total carbon estimation is 13.44～16.58 Tg during this 26years.The estimation of the year 1987 is about 1.97～2.47 Tg,which is 14.7%of the total carbon estimation during the 26 years in Daxing'an Mountains.And the total carbon fixation is 6.83～8.83 Tg,the mean fixation is 5.29～6.84 t/hm~2.Consequently,the carbon balance in the forest fires during 26 years is -7.75～6.61 Tg in Daxing'an Mountains.It indicates that the carbon estimated is more than the carbon fixed in the forest fires during 1980 to 2005.Comparing with the other grads fire,the carbon budget in burned area of mid-grade fire is positive.Thus,the mid-grade fire can promote the carbon fixation of the forest ecosystem and be helpful to enhance the carbon sink function.The result of the dynamic of the NPP following forest fires during the 26 years shows that the NPP of the burned area increases by the year after fire,and increases slowly 20 years post fire.The NPP of burned area is almost equal to,even more than that of unburned area when it was 23～24 years after fire.It suggests that the productivity of the tree in burned area was basically recovered when 23～24 years after fire.