| Chinese fir?Cunninghamia lanceolata?is an important fast growing timber species in China.In this study,27 samples of Chinese fir plantations of different forest ages in the south and west of Anhui province were taken as the research object.By combining the biomass relative growth equation method with the sample plot survey data,the temporal and spatial variation rules of tree layer,litter layer,soil layer and ecosystem carbon storage in Chinese fir plantations were explored.In addition,based on the sample survey data,explore the environmental factors influence on forest ecosystem carbon reserves,so as to evaluate the Chinese fir plantation ecosystem carbon"hui"function and under the background of global climate change,China's regional ecological environment construction and develop regional forest ecosystem carbon"hui"management measures so as to provide basis and reference.The main research results are as follows:?1?The range of biomass and carbon storage in the arboretum of Chinese fir plantation with different age sequences was 46.08?215.40 t·hm-2 and 22.45?108.58 t·hm-2,respectively.With the increase of forest age sequences,the variation trend of biomass and carbon storage in the arboretum of Chinese fir plantation was first increased,then decreased,and then increased,with the maximum above 35 a and the minimum below 15 a,and the difference between them was very significant?P<0.01?.The variation ranges of biomass and carbon storage in litters layer were 7.41?10.32 t·hm-2 and 2.12?2.98 t·hm-2,respectively.With the increase of forest age sequence,the variation trend of first decreasing,then increasing and then decreasing was shown,with the maximum below 15 a and the minimum between 21and 25 a,and the difference between the two was significant?P<0.05?.The variation range of carbon storage in soil layer is 61.70?108.34 t·hm-2.With the increase of forest age,it increases first,then decreases,then rises and then declines.The maximum value is 21?25 a,and the minimum value is below 15 a.The variation range of the carbon reserves in the ecosystem is 125.52?211.17 t·hm-2,which increases first,then decreases and then increases with the growth of the forest age sequence,and the maximum value is above 35 a and the minimum value is below 15 a,showing a very significant difference between the two?P<0.01?.This indicates that the carbon reserves at different levels of Chinese fir plantation vary in different age groups.In general,the carbon reserves in tree layer,soil layer and ecosystem increase with the growth of forest age,while the carbon reserves in litter layer decrease with the growth of forest age.?2?The biomass variation range of leaves,branches,stems and roots in each age stage was 4.85?11.94 t·hm-2,3.13?28.92 t·hm-2,28.81?129.94 t·hm-2 and 9.29?45.30 t·hm-2,and the variation range of carbon reserves was 2.44?6.10 t·hm-2,1.48?14.70 t·hm-2,14.19?64.62t·hm-2 and 4.33?23.17 t·hm-2,respectively.The biomass and carbon storage of leaves,branches,stems and roots in each forest age stage were the smallest under 15a and the largest above 35a,and the difference between them was extremely significant?P<0.01?.At different forest ages,the biomass of dry organs and carbon storage were the largest,followed by roots.This shows that the biomass of each component and the overall carbon reserves increase with the increase of forest age,and the biomass and carbon reserves of each forest age stage are mainly trunks,followed by the root.?3?The variation ranges of aboveground and underground biomass were 36.79?170.10t·hm-2 and 9.29?45.30 t·hm-2 at each age stage,respectively,with the maximum above 35a and the minimum below 15a,and the difference between the two was very significant?P<0.01?,while the difference between other age stages was not significant?P>0.05?.The proportion of aboveground and underground biomass in each forest age stage was79.81?83.35%and 16.65?20.19%,respectively.The ratio of aboveground and underground biomass of Chinese fir plantation was 0.196?0.286,which decreased first and then increased with the growth of forest age.This indicated that the aboveground biomass of Chinese fir plantation of different age sequences was higher than that of the underground part,and the aboveground biomass was higher than that of the underground part.This indicated that the biomass of the upper part of China fir forestland was higher than that of the underground part?4?In addition to 26?30 a,the soil carbon storage in the 0?50 cm soil layer decreases with the increase of soil depth in other forest age stages.The soil carbon storage in the 0?10cm,10?30 cm and 30?50 cm soil layers accounts for 43.85?49.98%,35.71?43.46%and8.20%?14.77%of the whole soil layer respectively,which are mainly in the 0?10 cm soil layer.The soil carbon storage in the 0?50 cm soil layer of the 26?30 a age group increased first and then decreased with the increase of soil depth.The carbon storage in the three soil layers respectively accounted for 42.40%,45.37%and 12.23%of the whole soil layer,with the majority being 10?30 cm.This may be because the litter content in the 26?30 a forest stage affects the soil carbon storage in the 10?30 cm soil layer.?5?With the exception of above 35 a,the carbon reserves of trees,litters and soil in the other age groups accounted for 25.76?36.61%,1.26%?3.42%and 62.76?70.81%of the whole ecosystem,respectively.The proportion of carbon reserves in the whole ecosystem at levels above 35 a was 52.49%,1.05%and 49.16%,respectively.?6?The carbon reserve sequestration of fir forest ecosystem has a significant positive correlation with diameter at breast height and tree height,and is close to significant negative correlation with forest density.The carbon reserve and soil bulk density of fir forest ecosystem have a significant negative correlation,positive correlation with soil organic carbon,and a close positive correlation with soil whole nitrogen.There was no significant correlation between carbon reserve and other factors of Chinese fir plantation ecosystem.Principal component analysis showed that chest diameter,tree height,stand density,soil bulk density,soil organic carbon,and soil total nitrogen were the main controlling factors affecting the carbon storage of the ecosystem,while longitude,latitude,altitude and slope were the key factors affecting the carbon storage of the ecosystem. |
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