Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecos...Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecosystem in terms of water and nutrient uptake. In this study the effects of thinning and litter fall removal on fine root production and soil organic carbon content were examined in 20-year-old Masson pine （Pinus resinosa） plantations in Huitong, Hunan Province of China in the growing seasons of 2004 and 2005. The results showed that fine root production was significantly lower in the thinning plots than in the control plots, with a decrease of 58% and 14% in 2004 and 2005 growing seasons, respectively. Litter fall removal significantly increased fine root production by 14% in 2004. Soil temperature （Tsoil） and soil moisture （Msoil） were higher in the thinning plots than those in the controls. Litter fall removal had significant effects on Tsoil and Msoil. Soil organic carbon content was higher in the thinning plots but was lower in the plots with litter fall removal compared with that in the controls. Our results also indicated that annual production of fine roots resulted in small carbon accumulation in the upper layers of the soil, and removal of tree by thinning resulted in a significant increase of carbon storage in Masson pine plantations.展开更多
Senesced-leaf nutrient concentrations vary signifcantly among coexisting plant species refecting different leaf nutrient use strategies.However,interspecifc variation in senesced-leaf nutrients and its driving factors...Senesced-leaf nutrient concentrations vary signifcantly among coexisting plant species refecting different leaf nutrient use strategies.However,interspecifc variation in senesced-leaf nutrients and its driving factors are not well understood.Here,we aimed to determine interspecifc variation and its driving factors in senesced-leaf nutrients.We explored interspecifc variation in carbon(C),nitrogen(N)and phosphorus(P)concentrations in newly fallen leaves of 46 coexisting temperate deciduous woody species across the Maoershan Forest Ecosystem Research Station,Northeast China.The relative importance of 10 biotic factors(i.e.mycorrhiza type,N-fxing type,growth form,shade tolerance,laminar texture,coloring degree,coloring type,peak leaf-coloration date,peak leaf-fall date and end leaf-fall date)was quantifed with the random forest model.N and P concentrations varied 4-and 9-fold among species,respectively.The high mean N(15.38 mg·g^(−1))and P(1.24 mg·g^(−1))concentrations suggested a weak N and P limitation in the studied forest.Functional groups had only signifcant effects on specifc nutrients and their ratios.P concentration and N:P were negatively correlated with peak and end leaf-fall dates for the ectomycorrhiza species group.Brighter-colored leaves(red>brown>yellow>yellow-green>green)tended to have lower N and P concentrations and higher C:N and C:P than darker-colored leaves.The random forest model showed that autumn coloration and leaf-fall phenology contributed 80%to the total explanation of nutrient variability among species.The results increase our understanding of the variability in senesced-leaf nutrients as a strategy of woody plant nutrition in temperate forests.展开更多
基金Supported by the "948" Grant of the National Forestry Administration of China (No.2007-4-19)the Special Grantof Chinese Forestry Public Benefits (Nos.200804030 and 2007-4-15)the Provincial Fund for Distinguished Young Scholars of Hunan, China (No.07JJ1004)
文摘Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecosystem in terms of water and nutrient uptake. In this study the effects of thinning and litter fall removal on fine root production and soil organic carbon content were examined in 20-year-old Masson pine （Pinus resinosa） plantations in Huitong, Hunan Province of China in the growing seasons of 2004 and 2005. The results showed that fine root production was significantly lower in the thinning plots than in the control plots, with a decrease of 58% and 14% in 2004 and 2005 growing seasons, respectively. Litter fall removal significantly increased fine root production by 14% in 2004. Soil temperature （Tsoil） and soil moisture （Msoil） were higher in the thinning plots than those in the controls. Litter fall removal had significant effects on Tsoil and Msoil. Soil organic carbon content was higher in the thinning plots but was lower in the plots with litter fall removal compared with that in the controls. Our results also indicated that annual production of fine roots resulted in small carbon accumulation in the upper layers of the soil, and removal of tree by thinning resulted in a significant increase of carbon storage in Masson pine plantations.
基金funded by the National Natural Science Foundation of China(32171765)the Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R09)。
文摘Senesced-leaf nutrient concentrations vary signifcantly among coexisting plant species refecting different leaf nutrient use strategies.However,interspecifc variation in senesced-leaf nutrients and its driving factors are not well understood.Here,we aimed to determine interspecifc variation and its driving factors in senesced-leaf nutrients.We explored interspecifc variation in carbon(C),nitrogen(N)and phosphorus(P)concentrations in newly fallen leaves of 46 coexisting temperate deciduous woody species across the Maoershan Forest Ecosystem Research Station,Northeast China.The relative importance of 10 biotic factors(i.e.mycorrhiza type,N-fxing type,growth form,shade tolerance,laminar texture,coloring degree,coloring type,peak leaf-coloration date,peak leaf-fall date and end leaf-fall date)was quantifed with the random forest model.N and P concentrations varied 4-and 9-fold among species,respectively.The high mean N(15.38 mg·g^(−1))and P(1.24 mg·g^(−1))concentrations suggested a weak N and P limitation in the studied forest.Functional groups had only signifcant effects on specifc nutrients and their ratios.P concentration and N:P were negatively correlated with peak and end leaf-fall dates for the ectomycorrhiza species group.Brighter-colored leaves(red>brown>yellow>yellow-green>green)tended to have lower N and P concentrations and higher C:N and C:P than darker-colored leaves.The random forest model showed that autumn coloration and leaf-fall phenology contributed 80%to the total explanation of nutrient variability among species.The results increase our understanding of the variability in senesced-leaf nutrients as a strategy of woody plant nutrition in temperate forests.
