以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白...以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白桦林)作为哑变量引入到预测模型中,对不同林型的林分碳密度进行预测,为林业研究中碳密度模型的构建以及森林碳汇工作提供思路和方法。结果表明,天然白桦林林分碳密度基础模型决定系数(R^(2))为0.703,均方根误差(RMSE)为8.615 t/hm^(2),赤池信息量(Akaike information criterion,AIC)为841.206,贝叶斯信息量(Bayesian Information Criterion,BIC)为851.071。引入立地条件哑变量后,R^(2)有所增大,最大达到0.818,RMSE均小于等于8.241 t/hm^(2),说明模型具有较好的稳定性,预估参数较为精确。哑变量模型的AIC均小于等于541.431,BIC均小于等于550.320。哑变量模型能够反映不同立地条件下碳密度的变化,在模型的拟合和检验方面都显示适合于研究地区林分碳密度的预测,为天然白桦林碳密度估算提供参考。展开更多
Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutr...Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutrients vary with tree size,organ age,or root order at the individual level remains limited.We determined C,N,and P contents and their stoichiometric ratios(i.e.,nutrient traits)in needles,branches,and fine roots at different organ ages(0-3-year-old needles and branches)and root orders(1st-4th order roots)from 64 Pinus koraiensis of varying size(Diameter at breast height ranged from 0.3 to 100 cm)in northeast China.Soil factors were also measured.The results show that nutrient traits were regulated by tree size,organ age,or root order rather than soil factors.At a whole-plant level,nutrient traits decreased in needles and fine roots but increased in branches with tree size.At the organ level,age or root order had a negative effect on C,N,and P and a positive effect on stoichiometric ratios.Our results demonstrate that nutrient variations are closely related to organ-specific functions and ecophysiological processes at an individual level.It is suggested that the nutrient acquisition strategy by younger trees and organ fractions with higher nutrient content is for survival.Conversely,nutrient storage strategy in older trees and organ fractions are mainly for steady growth.Our results clarified the nutrient utilization strategies during tree and organ ontogeny and suggest that tree size and organ age or root order should be simultaneously considered to understand the complexities of nutrient variations.展开更多
The role of the temperate mixed broadleaf-Korean pine forest(BKF)in global biogeochemical cycles will depend on how the tree species community responds to climate;however,species-specific responses and vulner-abilitie...The role of the temperate mixed broadleaf-Korean pine forest(BKF)in global biogeochemical cycles will depend on how the tree species community responds to climate;however,species-specific responses and vulner-abilities of common trees in BKF to extreme climates are poorly understood.Here we used dendrochronological meth-ods to assess radial growth of seven main tree species(Pinus koraiensis,Picea jezoensis,Abies nephrolepis,Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Ulmus davidiana)in an old-growth BKF in response to climate changes in the Xiaoxing’an Mountains and to improve predictions of changes in the tree species compo-sition.Temperature in most months and winter precipita-tion significantly negatively affected growth of P.jezoensis and A.nephrolepis,but positively impacted growth of P.koraiensis and the broadleaf species,especially F.mandshu-rica and U.davidiana.Precipitation and relative humidity in June significantly positively impacted the growth of most tree species.The positive effect of the temperature during the previous non-growing season(PNG)on growth of F.mandshurica and Q.mongolica strengthened significantly with rapid warming around 1981,while the impact of PNG temperature on the growth of P.jezoensis and A.nephrolepis changed from significantly negative to weakly negative or positive at this time.The negative response of radial growth of P.jezoensis and A.nephrolepis to precipitation during the growing season gradually weakened,and the negative response to PNG precipitation was enhanced.Among the studied species,P.koraiensis was the most resistant to drought,and U.davidiana recovered the best after extreme drought.Ulmus davidiana,P.jezoensis and A.nephrolepis were more resistant to extreme cold than the other species.Climate warming generally exacerbated the opposite growth patterns of conifer(decline)and broadleaf(increase)spe-cies.Deciduous broadleaf tree species in the old-growth BKF probably will gradually become dominant as warming continues.Species-specific growth-climate relationships should be considered in future models of biogeochemical cycles and in forestry management practices.展开更多
文摘以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白桦林)作为哑变量引入到预测模型中,对不同林型的林分碳密度进行预测,为林业研究中碳密度模型的构建以及森林碳汇工作提供思路和方法。结果表明,天然白桦林林分碳密度基础模型决定系数(R^(2))为0.703,均方根误差(RMSE)为8.615 t/hm^(2),赤池信息量(Akaike information criterion,AIC)为841.206,贝叶斯信息量(Bayesian Information Criterion,BIC)为851.071。引入立地条件哑变量后,R^(2)有所增大,最大达到0.818,RMSE均小于等于8.241 t/hm^(2),说明模型具有较好的稳定性,预估参数较为精确。哑变量模型的AIC均小于等于541.431,BIC均小于等于550.320。哑变量模型能够反映不同立地条件下碳密度的变化,在模型的拟合和检验方面都显示适合于研究地区林分碳密度的预测,为天然白桦林碳密度估算提供参考。
基金supported by the National Key R&D Program of China (2022YFD2201100)Natural Science Foundation of Heilongjiang Province of China (TD2023C006)the Fundamental Research Funds for the Central Universities (2572022DS13).
文摘Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutrients vary with tree size,organ age,or root order at the individual level remains limited.We determined C,N,and P contents and their stoichiometric ratios(i.e.,nutrient traits)in needles,branches,and fine roots at different organ ages(0-3-year-old needles and branches)and root orders(1st-4th order roots)from 64 Pinus koraiensis of varying size(Diameter at breast height ranged from 0.3 to 100 cm)in northeast China.Soil factors were also measured.The results show that nutrient traits were regulated by tree size,organ age,or root order rather than soil factors.At a whole-plant level,nutrient traits decreased in needles and fine roots but increased in branches with tree size.At the organ level,age or root order had a negative effect on C,N,and P and a positive effect on stoichiometric ratios.Our results demonstrate that nutrient variations are closely related to organ-specific functions and ecophysiological processes at an individual level.It is suggested that the nutrient acquisition strategy by younger trees and organ fractions with higher nutrient content is for survival.Conversely,nutrient storage strategy in older trees and organ fractions are mainly for steady growth.Our results clarified the nutrient utilization strategies during tree and organ ontogeny and suggest that tree size and organ age or root order should be simultaneously considered to understand the complexities of nutrient variations.
基金supported by the National Natural Science Foundation of China(42107476,41877426)the Hunan Provincial Natural Science Foundation of China(2021JJ41075)+3 种基金the China Postdoctoral Science Foundation(2020M682600)the Science and Technology Innovation Program of Hunan Province(2020RC2058)the Research Foundation of the Bureau of Education in Hunan Province(20B627)China Scholarship Council(CSC,no.202206600004,to DY).
文摘The role of the temperate mixed broadleaf-Korean pine forest(BKF)in global biogeochemical cycles will depend on how the tree species community responds to climate;however,species-specific responses and vulner-abilities of common trees in BKF to extreme climates are poorly understood.Here we used dendrochronological meth-ods to assess radial growth of seven main tree species(Pinus koraiensis,Picea jezoensis,Abies nephrolepis,Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Ulmus davidiana)in an old-growth BKF in response to climate changes in the Xiaoxing’an Mountains and to improve predictions of changes in the tree species compo-sition.Temperature in most months and winter precipita-tion significantly negatively affected growth of P.jezoensis and A.nephrolepis,but positively impacted growth of P.koraiensis and the broadleaf species,especially F.mandshu-rica and U.davidiana.Precipitation and relative humidity in June significantly positively impacted the growth of most tree species.The positive effect of the temperature during the previous non-growing season(PNG)on growth of F.mandshurica and Q.mongolica strengthened significantly with rapid warming around 1981,while the impact of PNG temperature on the growth of P.jezoensis and A.nephrolepis changed from significantly negative to weakly negative or positive at this time.The negative response of radial growth of P.jezoensis and A.nephrolepis to precipitation during the growing season gradually weakened,and the negative response to PNG precipitation was enhanced.Among the studied species,P.koraiensis was the most resistant to drought,and U.davidiana recovered the best after extreme drought.Ulmus davidiana,P.jezoensis and A.nephrolepis were more resistant to extreme cold than the other species.Climate warming generally exacerbated the opposite growth patterns of conifer(decline)and broadleaf(increase)spe-cies.Deciduous broadleaf tree species in the old-growth BKF probably will gradually become dominant as warming continues.Species-specific growth-climate relationships should be considered in future models of biogeochemical cycles and in forestry management practices.
