To study the effect of thinning intensity on the carbon sequestration by natural mixed coniferous and broad-leaf forests in Xiaoxing’an Mountains,China,we established six 100 m×100 m experimental plots in Dongfa...To study the effect of thinning intensity on the carbon sequestration by natural mixed coniferous and broad-leaf forests in Xiaoxing’an Mountains,China,we established six 100 m×100 m experimental plots in Dongfanghong For-est that varied in thinning intensity:plot A(10%),B(15%),C(20%),D(25%),E(30%),F(35%),and the control sample area(0%).A principal component analysis was performed using 50 different variables,including species diversity,soil fertility,litter characteristics,canopy structure param-eters,and seedling regeneration parameters.The effects of thinning intensity on carbon sequestration were strongest in plot E(0.75),followed by D(0.63),F(0.50),C(0.48),B(0.22),A(0.11),and the control(0.06).The composite score of plot E was the highest,indicating that the carbon sequestration effect was strongest at a thinning intensity of 30%.These findings provide useful insights that could aid the management of natural mixed coniferous and broadleaf forests in Xiaoxing’an Mountains,China.This information has implications for future studies of these forests,and the methods used could aid future ecological assessments of the natural forests in Xiaoxing’an Mountains,China.展开更多
Background:Metabolic scaling theory(MST)is still in debate because observed allometric exponents often deviate from MST predictions,and can change significantly depending on environment,phylogeny,and disturbance.We as...Background:Metabolic scaling theory(MST)is still in debate because observed allometric exponents often deviate from MST predictions,and can change significantly depending on environment,phylogeny,and disturbance.We assembled published scaling exponents from literatures for three allometric relationships linked to biomass allocation:leaf biomassdiameter(LD),stem biomassdiameter(SD),and root biomassdiameter(RD).We used data from natural forests and plantations across China to test the following hypotheses:1)the allometric relationships of trees support the predictions of MST on a broad scale;2)the observed deviations from MST predictions are caused by climate,biotic factors,and/or phylogeny;3)abiotic and biotic factors influence allometric relationships in plantations and natural forests differently,and different allometric relationships(i.e.LD,SD,and RD)are affected differently.We related these scaling exponents to geographic climate gradient,successional stage,stand density,leaf form and phenology,and phylogeny.We used mixedeffect models to examine the major factors affecting tree allometries.Results:In natural forests,SD and RD scaling exponents were consistent with MST predictions in primary forests,but were significantly lower in secondary forests.Both SD and RD scaling exponents in plantations had a medium value that fell between those of the secondary and primary forests,despite plantations being similar in species characteristics and age to secondary forests.The SD and RD exponents were significantly affected by factors that are not yet considered in MST,including winter coldness which explained 2.76%–3.24%of variations,successional stage(7.91%–8.20%of variations),density(a surrogate for competition,5.86%–8.54%of variations),and especially phylogeny(45.86%–56.64%of variations explained).However,the LD scaling exponents conformed to MST predictions in primary,secondary,and plantation forests,and was not strongly explained by most factors.Conclusion:MST is only applicable to primary(steadystate)forests,and climate,biotic factors and phylogeny are causes of the observed deviations of allometric relationships from MST predictions.Forest management practices in plantations have a strong influence on tree allometries.LD allometry is more strongly controlled by biophysical constraints than SD and RD allometries,however,the mechanisms behind this difference still need further examinations.展开更多
基金funded by National Key Research and development project(2022YFD2201001)Project for Applied TechnologyResearch and Development in Heilongjiang Province(GA19C006).
文摘To study the effect of thinning intensity on the carbon sequestration by natural mixed coniferous and broad-leaf forests in Xiaoxing’an Mountains,China,we established six 100 m×100 m experimental plots in Dongfanghong For-est that varied in thinning intensity:plot A(10%),B(15%),C(20%),D(25%),E(30%),F(35%),and the control sample area(0%).A principal component analysis was performed using 50 different variables,including species diversity,soil fertility,litter characteristics,canopy structure param-eters,and seedling regeneration parameters.The effects of thinning intensity on carbon sequestration were strongest in plot E(0.75),followed by D(0.63),F(0.50),C(0.48),B(0.22),A(0.11),and the control(0.06).The composite score of plot E was the highest,indicating that the carbon sequestration effect was strongest at a thinning intensity of 30%.These findings provide useful insights that could aid the management of natural mixed coniferous and broadleaf forests in Xiaoxing’an Mountains,China.This information has implications for future studies of these forests,and the methods used could aid future ecological assessments of the natural forests in Xiaoxing’an Mountains,China.
基金the Fundamental Research Funds for the Central Universities(BLX201802)National Natural Science Foundation of China(31870430)the National Key Research and Development Program of China(#2017YFC0503901).
文摘Background:Metabolic scaling theory(MST)is still in debate because observed allometric exponents often deviate from MST predictions,and can change significantly depending on environment,phylogeny,and disturbance.We assembled published scaling exponents from literatures for three allometric relationships linked to biomass allocation:leaf biomassdiameter(LD),stem biomassdiameter(SD),and root biomassdiameter(RD).We used data from natural forests and plantations across China to test the following hypotheses:1)the allometric relationships of trees support the predictions of MST on a broad scale;2)the observed deviations from MST predictions are caused by climate,biotic factors,and/or phylogeny;3)abiotic and biotic factors influence allometric relationships in plantations and natural forests differently,and different allometric relationships(i.e.LD,SD,and RD)are affected differently.We related these scaling exponents to geographic climate gradient,successional stage,stand density,leaf form and phenology,and phylogeny.We used mixedeffect models to examine the major factors affecting tree allometries.Results:In natural forests,SD and RD scaling exponents were consistent with MST predictions in primary forests,but were significantly lower in secondary forests.Both SD and RD scaling exponents in plantations had a medium value that fell between those of the secondary and primary forests,despite plantations being similar in species characteristics and age to secondary forests.The SD and RD exponents were significantly affected by factors that are not yet considered in MST,including winter coldness which explained 2.76%–3.24%of variations,successional stage(7.91%–8.20%of variations),density(a surrogate for competition,5.86%–8.54%of variations),and especially phylogeny(45.86%–56.64%of variations explained).However,the LD scaling exponents conformed to MST predictions in primary,secondary,and plantation forests,and was not strongly explained by most factors.Conclusion:MST is only applicable to primary(steadystate)forests,and climate,biotic factors and phylogeny are causes of the observed deviations of allometric relationships from MST predictions.Forest management practices in plantations have a strong influence on tree allometries.LD allometry is more strongly controlled by biophysical constraints than SD and RD allometries,however,the mechanisms behind this difference still need further examinations.
