The Influence Of Thinning Intensity On Soil Carbon Storage In Typical Forest Stands In Changbai Mountain

This paper based on shaw stand,poplar-birch stand and larch-birch stand which are located in Changbai Mountain,exploring litter decomposition and accumulation,seasonal soil respiration rate and soil carbon storage density under different thinning treatment of Young age and Middle age forest.Get the following conclusions through the analysis of the data processing.The First:Influence on litter under different thinning treatmentThe impact of different thinning treatment on litter decomposition and accumulation with different age and forest type is discriminatory.The influence on litter carbon content rate and C/N rate under thinning treatment is not significant,carbon content and C/N rate are remain at a steady state.Meantime,the difference of carbon content rate of not decomposition layer and decomposition layer is also not significant;after 150 days litter decomposition experiment,all forest stand's litter weight loss rate are descending along with time goes by,litter carbon release weight all over 30%of the initial carbon weight at the end of this experiment.The order of litter standing crop of Young age shaw stand is T0(11.50 t·hm^-2)>T1(9.27 t-hm^-2)>T2(7.12 t·hm^-2),The order of litter standing crop of Middle age shaw stand is T0(11.13 t·hm^-2)>T1(10.97 t·hm^-2)>T2(10.63 t·hm^-2),The order of litter standing crop of Young age poplar-birch stand is T0(10.25 t·hm^-2)>T2(7.95t·hm^-2)>T1(5.15t·hm^-2).The order of litter standing crop of Middle age poplar-birch stand is T1(7.98t-hm^-2)>T2(5.38 t·hm^-2)>T0(5.3lt·hm^-2),The order of litter standing crop of Young age larch-birch stand is T1(10.78t·hm^-2)>T0(9.09 t·hm^-2)>T2(8.03t·hm^-2),The order of litter standing crop of Middle age larch-birch stand is T0?14.10 t-hm"2?>T2(7.54 t·hm^-2)>T1(7.27 t·hm^-2).The second:The effect of thinning treatment on soil respiration rateSoil respiration rate has obvious seasonal differences and different thinning intensity also has diverse impact on soil respiration rate of each forest type.Young age and Middle age shaw stand's soil respiration rate is increasing along with thinning treatment grows.Young age and Middle age poplar-birch stand's soil respiration rate decreases with the increase of thinning intensity.Young age and Middle age larch-birch stand's soil respiration rate has a downward trend along with thinning intensity increasing.We get the regression coefficient?R2?between each stand's soil temperature at different depth and soil respiration rate through using an exponential model.The R2 of Young age shaw stand is 0.4723-0.6158,Middle age shaw stand is 0.6079-0.7503,Young age poplar-birch stand is 0.2682-0.6662,Middle age poplar-birch stand is 0.6079-0.7705,Young age larch-birch stand is 0.0671-0.263,Middle age larch-birch stand is 0.031 9-0.7749.we also get each stand's Q10 value by the exponential equation and find that except poplar-birch stand,Young age stand's Q10 is higher than Middle age for other two type of stands at different thinning treatment.We calculate the mean growing season soil respiration rate(?moICO2m^-2·s-1)of each forest stands under different thinning treatment,Young age shaw stand is T2?2.71?>T1?2.40?>T0?1.95?,Middle age shaw stand is T2?2.57?=T1?2.57?>T0?2.08?,Young age poplar-birch stand isT0?2.34?>T1?1.98?>T2?1.82?,Middle age poplar-birch stand is T0?2.26?>T1?2.05?>T2?1.58?,Young age larch-birch stand is T1?1.96?>T0?1.81?>T2?1.39?,Middle age Larch-birch stand is T0?2.00?>T1?1.83?>T2?1.73?.The third:The effect of thinning treatment on soil carbon storage densityThinning treatment has no significant impact on soil carbon content rate,each soil layer's carbon content rate doesn't show significant regular with the thinning treatment is changing,and they all remain at a stable state relatively.On the other hand,soil carbon storage density shows significant change rules under different thinning treatment intensity and the carbon storage density of all the stands show following:Young age shaw stand is T0(110.80 t·hm^-2)>T1(73.58 t·hm^-2)>T2(53.37 t·hm^-2),Middle age shaw stand is T0(217.47t·hm^-2)>T1(163.53t·hm^-2)>T2(153.04t·hm^-2);Young age poplar-birch stand is T1(105.3t·hm^-2)>T0(97.56t·hm^-2)>T2(96.97t·hm^-2),Middle age poplar-birch stand is T1(138.28t·hm^-2)>T0(115.48 t·hm^-2)>T2(98.50t·hm^-2);Young age larch-birch stand is T0(84.68t·hm^-2)>T1(75.28 t·hm^-2)>T2(73.23t·hm^-2),Middle age larch-birch stand is T0(110.43t·hm^-2)>T1(88.07t·hm^-2)>T2(86.12 t·hm^-2).Middle age stand's carbon storage density is higher than Young age stand under each thinning treatments.On the whole,the sorting of three forest stands' carbon storage density is poplar-birch stand>shaw stand>larch-birch stand.The fourth:Suitable thinning treatment intensity for three forest stand typesSuitable thinning intensity for Young age and Middle age shaw stand is high strength and should keep stand's density at 800 plants per hectare and 500 plants per hectare.Young age and Middle age poplar-birch stands should take conventional thinning treatment and keep stand's density at 1800 plants per hectare and 2200 plants per hectare.Young age larch-birch stand should use conventional thinning treatment and keep stand's density at 2000 plants per hectare.Middle age larch-birch stands should keep present stand's density which is 1000 plants per hectare could reach the goal to maintain forest stand be a "carbon sink".