Changes In Carbon Storage,plant Diversity And Community Structure Of Forests In Daxing'an Mts Under Different Fire Rehabilitation Years

Forest fire is an important factor controlling forest ecosystem successions in the Daxing'an Mountains,Northeastern China,while long-term temporal dynamics in plant diversity and species abundance are still very limited to date,for modeling forest ecological services variations.This study selected 48-paired plots at Huzhong,Nanwenghe,Shuanghe,Tuqiang,Tahe,Jagedaqi and Mangui,using the neighbor un-fired site as control(the similar terrain).The effects of burning time(1-5 years,5-10 years,10-20 years,20-30 years,30-40 years,40-50 years)on forest carbon,biodiversity index and community structure index(a total of 33 factors)were studied by using fire and ratio and difference change of the same land to the same area.We found that:(1)In terms of forest carbon:the effects of fire on the carbon storage of forest vegetation on the forest are:arbor layer>shrub layer>herb layer,and the arbor layer and shrub layer reach the control level after recovery for 30-40 years.The total carbon content showed a linear upward trend with the increase of the age of fire(p<0.05),and reached the control level after 30 years of fire.The flammability and drought resistance of trees reached the control level in 20-30 years.(2)In terms of plant diversity and dominant species:Tree and shrub diversity index decreased first and then increased.It is the lowest in the fire for about 10 years and the maximum in the next 30 years,which is equivalent to the control.The Herb Simpson diversity index showed a linear decline with recovery time.The relative abundance of key species of arbor is more complicated.It has not reached the control level after 50 years of recovery,while shrubs and herbs recover faster,and key species have similar control in 30 years.After 40-50 years of recovery,the plant composition has a tendency to dry out,showing an increasing trend of Quercus mongolica Fisch.ex Ledeb.,Corylus heterophylla Fisch.and Carex callitrichos V.Krecz.(3)In terms of community structure,tree height,branch height and DBH increased linearly with the increase of fire age(p<0.05).The fire level is reached in the fire for 30-40 years.Herbaceous grass height and grass cover decreased with increasing fire age.(4)In terms of the coupling relationship between forest carbon,diversity and community structure and natural geographical factors:PCA ranking results of natural geographical factors and soil indicators,biochar indicators,plant diversity and community structure indicators show that the fire recovery period contributes to it maximum.Studying the changes of forest carbon,biodiversity and community structure in the Daxing'an Mts under the long-term restorative fire age is helpful to understand the long-term effects of forest fire on the post-combustion recovery of the Daxing'an Mts,and provide theoretical basis and scientific evaluation for the scientific management of the Daxing'an Mts forest ecosystem.