Effects Of Understory Removal On Carbon Budget Of Eucalyptus Plantation

In order to reveal the effects of understory removal on carbon budget of Eucalyptus plantation,a 4-years-old Eucalyptus plantation was studied at compartment 67th in Qingshan testing field of China Forest Science Tropical Forestry Experimental Center,Pingxiang City,Guangxi Province,China.We examined the net carbon sequestration increment of tree layer,litter layer and soil layer of the Eucalyptus plantations,the soil respiration rate,the annual carbon emissions of soil respiration through field control test,field observation and laboratory analysis.The main conclusions are as follows:(1)Understory removal significantly reduced the net carbon sequestration of Eucalyptus plantations.But the different components were different.The annual net carbon stocks of the tree layer in(18.47±0.38 t·C/hm2)the understory removal plot was significantly higher than that in the control plot(17.49±0.39 t ·Cyhm2.While the annual net carbon stocks of Litter layer(0.55±0.01 t·C/hm2),soil layer(1.27 ±0.05 t·C/hm2),ecosystem(20.29±0.38 t ·C/hm2)of the understory removal plot was significantly lower than the control plot(litter layer:0.62 ± 0.02 t·C/hm2,soil layer:2.48±0.13 t·C/hm2,ecosystem:22.52±0.41 t·C/hm2).(2)Understory removal has significant influence on soil respiration rate of Eucalyptus plantation.In the two different treatments,the soil respiration rate of Eucalyptus plantation showed very significant monthly dynamic and significant seasonal dynamic characteristics.The peak of soil respiration rate appeared in August and the valley was in January.The soil respiration rate of the understory removal plot was lower than that of the control plot,And show the trend of summer>spring>autumn>winter;The total carbon footprint of soil respiration(8.26±0.03 t·C/hm2)was significantly lower than that of the control plot(8.75 ± 0.15 t·C/hm2).(3)Understory removal significantly affected the net carbon budget of Eucalyptus Plantation.The net carbon budget(12.03±0.38 t·C/hm2)was significantly lower than that in the control plot(13.77±0.42 t·C/hm2),which was significantly lower than that of the control.In the two different treatments,the Eucalyptus plantations showed carbon sinks,but understory removalsignificantly reduced the carbon sink intensity of Eucalyptus plantation.