Permanent sample plots were set up for researching interspecific relationship of the artificia1 larch stand mixed with natural ash in the slash site in Maoershan Experiment Forestry Farm of Northeast Forestry Universi...Permanent sample plots were set up for researching interspecific relationship of the artificia1 larch stand mixed with natural ash in the slash site in Maoershan Experiment Forestry Farm of Northeast Forestry University. All trees in the plots were taken as objective trees and tree number,DBH, distance between trees and that of crown diameter were measured in range of 1-6m from every objective tree. Then study by Alemdag competition index, variance analysis and quantitation method were made. The result showed that the intraspecific competition was more intensive than the interspecific competition. Especially the competition between larch and ash was least relatively. For these kinds of site, the suitable mixture at 20-30 ages should be 2800 Ind/hm2 in density and 2 larch;1 ash in mixed ratio, which might improve site condition to promote stand produetivity.展开更多
Previous research has shown that competition between plants can have differential effects on leaf stoichiometry and non-structural carbohydrate(NSC)in different environments.However,little attention has been given to ...Previous research has shown that competition between plants can have differential effects on leaf stoichiometry and non-structural carbohydrate(NSC)in different environments.However,little attention has been given to understanding these effects on non-photosynthetic organs,particularly of deciduous tree species.Here we assess the impact of competition on below and aboveground biomass,stoichiometry,nutrient composition and NSC in pure and mixed forests of two Larch species,Larix kaempferi and L.olgensis under nitrogen(N)addition.Nitrogen enrichment did not result in stronger intraspecific competition for both species and L.olgensis benefited from the presence of L.kaempferi under different N levels.Stems kept relatively stable C/N compared to roots and branches in response to competition,while N addition imposed stronger impacts on N/P of different organs rather than competition.In contrast to stable C concentrations,starch and soluble sugar concentrations were more easily impacted by competition and the addition of nitrogen.Competition forced L.kaempferi and L.olgensis to allocate more carbon into storage by increasing their starch concentration and starch/soluble sugar of stems under competition.However,no significant differences in stoichiometry and NSC concentration between intra-and interspecific competition were found.NSC and nutrient pools of L.kaempferi stems,branches and coarse roots consistently declined due to competition regardless of N addition.Coarse and fine roots of L.kaempferi accumulated more N when in competition with L.olgensis than with a conspecific neighbor under N addition.Our results show that NSC was more sensitive to competition relative to stoichiometric traits(N and P)of non-photosynthetic organs.展开更多
Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerni...Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.展开更多
According to field investigation data,the intraspecific competition and interspecific competition of Pinus koraiensis in broad-leaved Korean pine mixed forest in Changbai Mountains were studied by using Hegyi’s compe...According to field investigation data,the intraspecific competition and interspecific competition of Pinus koraiensis in broad-leaved Korean pine mixed forest in Changbai Mountains were studied by using Hegyi’s competition index model for individual tree.The results showed that intraspecific competition intensity of Pinus koraiensis reduced with increase of diameter scale of trees.The order of competition intensity is:Pinus koraiensis-Fraxinus mandshurica>Pinus koraiensis-Quercus mongolica>Pinus koraiensis-Pinus koraiensis>Pinus koraiensis-Tilia amurensis>Pinus koraiensis-Acer mono>Pinus koraiensis-Tilia mandshurica>Pinus koraiensis-Acer mandshurica.The relationship between competition intensity and individual size of objective tree follows closely the equation CI =AD-B.Based on the relationship,competition intensity in the forest is simulated.At the same time,some conclusions and suggestions are proposed.It is proved that Hegyi′s competition model for individual tree can provide quantitative index for study on intraspecific and interspecific relationship in plant population ecology.展开更多
文摘Permanent sample plots were set up for researching interspecific relationship of the artificia1 larch stand mixed with natural ash in the slash site in Maoershan Experiment Forestry Farm of Northeast Forestry University. All trees in the plots were taken as objective trees and tree number,DBH, distance between trees and that of crown diameter were measured in range of 1-6m from every objective tree. Then study by Alemdag competition index, variance analysis and quantitation method were made. The result showed that the intraspecific competition was more intensive than the interspecific competition. Especially the competition between larch and ash was least relatively. For these kinds of site, the suitable mixture at 20-30 ages should be 2800 Ind/hm2 in density and 2 larch;1 ash in mixed ratio, which might improve site condition to promote stand produetivity.
基金supported by Zhejiang Provincial Natural Science Foundation of China(LQ18C030003,LQ18C160004)Starting Research Fund from Hangzhou Normal University(2018QDL006)。
文摘Previous research has shown that competition between plants can have differential effects on leaf stoichiometry and non-structural carbohydrate(NSC)in different environments.However,little attention has been given to understanding these effects on non-photosynthetic organs,particularly of deciduous tree species.Here we assess the impact of competition on below and aboveground biomass,stoichiometry,nutrient composition and NSC in pure and mixed forests of two Larch species,Larix kaempferi and L.olgensis under nitrogen(N)addition.Nitrogen enrichment did not result in stronger intraspecific competition for both species and L.olgensis benefited from the presence of L.kaempferi under different N levels.Stems kept relatively stable C/N compared to roots and branches in response to competition,while N addition imposed stronger impacts on N/P of different organs rather than competition.In contrast to stable C concentrations,starch and soluble sugar concentrations were more easily impacted by competition and the addition of nitrogen.Competition forced L.kaempferi and L.olgensis to allocate more carbon into storage by increasing their starch concentration and starch/soluble sugar of stems under competition.However,no significant differences in stoichiometry and NSC concentration between intra-and interspecific competition were found.NSC and nutrient pools of L.kaempferi stems,branches and coarse roots consistently declined due to competition regardless of N addition.Coarse and fine roots of L.kaempferi accumulated more N when in competition with L.olgensis than with a conspecific neighbor under N addition.Our results show that NSC was more sensitive to competition relative to stoichiometric traits(N and P)of non-photosynthetic organs.
基金This publication is based upon work from COST Action CLIMO(CA15226) supported by COST (European Cooperation in Science and Technology)the UMBRACLIM project (PID2019-111781RB-I00)funded by the Spanish Ministry for Science and Innovation. Teresa Valor was contracted with a grant“Juan de la Cierva-Formaci on”(FJC2018-036673-I). Z.S. received funds from the grant no. APVV-20-0365 and from project TreeAdapt supported by the MPRV SR. Aitor Ameztegui is supported by a Serra-Húnter fellowship by the Generalitat de Catalunya。
文摘Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.
文摘According to field investigation data,the intraspecific competition and interspecific competition of Pinus koraiensis in broad-leaved Korean pine mixed forest in Changbai Mountains were studied by using Hegyi’s competition index model for individual tree.The results showed that intraspecific competition intensity of Pinus koraiensis reduced with increase of diameter scale of trees.The order of competition intensity is:Pinus koraiensis-Fraxinus mandshurica>Pinus koraiensis-Quercus mongolica>Pinus koraiensis-Pinus koraiensis>Pinus koraiensis-Tilia amurensis>Pinus koraiensis-Acer mono>Pinus koraiensis-Tilia mandshurica>Pinus koraiensis-Acer mandshurica.The relationship between competition intensity and individual size of objective tree follows closely the equation CI =AD-B.Based on the relationship,competition intensity in the forest is simulated.At the same time,some conclusions and suggestions are proposed.It is proved that Hegyi′s competition model for individual tree can provide quantitative index for study on intraspecific and interspecific relationship in plant population ecology.
