Background： Tropical forests play an important role in the global carbon（C） cycle.However, tropical montane forests have been studied less than tropical lowland forests, and their role in carbon storage is not well...Background： Tropical forests play an important role in the global carbon（C） cycle.However, tropical montane forests have been studied less than tropical lowland forests, and their role in carbon storage is not well understood.Montane forests are highly endangered due to logging, land-use and climate change.Our objective was to analyse how the carbon balance changes during forest succession.Methods： In this study, we used a method to estimate local carbon balances that combined forest inventory data with process-based forest models.We utilised such a forest model to study the carbon balance of a tropical montane forest in South Ecuador, comparing two topographical slope positions（ravines and lower slopes vs upper slopes and ridges）.Results： The simulation results showed that the forest acts as a carbon sink with a maximum net ecosystem exchange（NEE） of 9.3 Mg C？（ha？yr）-1during its early successional stage（0–100 years）.In the late successional stage, the simulated NEE fluctuated around zero and had a variation of 0.77 Mg C？（ha？yr）–1.The simulated variability of the NEE was within the range of the field data.We discovered several forest attributes（e.g., basal area or the relative amount of pioneer trees） that can serve as predictors for NEE for young forest stands（0–100 years） but not for those in the late successional stage（500–1,000 years）.In case of young forest stands these correlations are high, especially between stand basal area and NEE.Conclusion： In this study, we used an Ecuadorian study site as an example of how to successfully link a forest model with forest inventory data, for estimating stem-diameter distributions, biomass and aboveground net primary productivity.To conclude, this study shows that process-based forest models can be used to investigate the carbon balance of tropical montane forests.With this model it is possible to find hidden relationships between forest attributes and forest carbon fluxes.These relationships promote a better 展开更多
Background：Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for for...Background：Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for forest conservation,restoration and sustainable management.Forest development through time is conventionally described as a directional,or ＂linear＂,and predictable sequence of stages from ＂bare ground＂ to old forest representing the ＂climax-state＂.However,this simple view is incompatible with the current knowledge and understanding of intrinsic variability of forest dynamics.Hypothesis：Overly simple conceptual models of forest dynamics easily become transformed into biased mental models of how forests naturally develop and what kind of structures they display.To be able to communicate the essential features and diversity of forest dynamics,comprehensive conceptual models are needed.For this end,Kuuluvainen（2009） suggested a relatively simple conceptual model of forest dynamics,which separates three major modes of forest dynamics,and incorporates state changes and transitions between the forest dynamics modes depending on changes in disturbance regime.Conclusions：Conceptual models of forest dynamics should be comprehensive enough to incorporate both longterm directional change and short-term cyclic forest dynamics,as well as transitions from one dynamics mode to another depending on changes in the driving disturbance regime type.Models that capture such essential features of forest dynamics are indispensable for educational purposes,in setting reference conditions and in developing methods in forest conservation,restoration and ecosystem management.展开更多
基金financial support of the German Research Foundation(DFG,Research Unit 816)for initializing the forest plots and the plot census as well as a first model parameterisationthe Helmholtz Alliance:Remote Sensing and Earth System Dynamics for financing the work on the further parameterisation of the model and analysis of the data
文摘Background： Tropical forests play an important role in the global carbon（C） cycle.However, tropical montane forests have been studied less than tropical lowland forests, and their role in carbon storage is not well understood.Montane forests are highly endangered due to logging, land-use and climate change.Our objective was to analyse how the carbon balance changes during forest succession.Methods： In this study, we used a method to estimate local carbon balances that combined forest inventory data with process-based forest models.We utilised such a forest model to study the carbon balance of a tropical montane forest in South Ecuador, comparing two topographical slope positions（ravines and lower slopes vs upper slopes and ridges）.Results： The simulation results showed that the forest acts as a carbon sink with a maximum net ecosystem exchange（NEE） of 9.3 Mg C？（ha？yr）-1during its early successional stage（0–100 years）.In the late successional stage, the simulated NEE fluctuated around zero and had a variation of 0.77 Mg C？（ha？yr）–1.The simulated variability of the NEE was within the range of the field data.We discovered several forest attributes（e.g., basal area or the relative amount of pioneer trees） that can serve as predictors for NEE for young forest stands（0–100 years） but not for those in the late successional stage（500–1,000 years）.In case of young forest stands these correlations are high, especially between stand basal area and NEE.Conclusion： In this study, we used an Ecuadorian study site as an example of how to successfully link a forest model with forest inventory data, for estimating stem-diameter distributions, biomass and aboveground net primary productivity.To conclude, this study shows that process-based forest models can be used to investigate the carbon balance of tropical montane forests.With this model it is possible to find hidden relationships between forest attributes and forest carbon fluxes.These relationships promote a better
文摘Background：Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for forest conservation,restoration and sustainable management.Forest development through time is conventionally described as a directional,or ＂linear＂,and predictable sequence of stages from ＂bare ground＂ to old forest representing the ＂climax-state＂.However,this simple view is incompatible with the current knowledge and understanding of intrinsic variability of forest dynamics.Hypothesis：Overly simple conceptual models of forest dynamics easily become transformed into biased mental models of how forests naturally develop and what kind of structures they display.To be able to communicate the essential features and diversity of forest dynamics,comprehensive conceptual models are needed.For this end,Kuuluvainen（2009） suggested a relatively simple conceptual model of forest dynamics,which separates three major modes of forest dynamics,and incorporates state changes and transitions between the forest dynamics modes depending on changes in disturbance regime.Conclusions：Conceptual models of forest dynamics should be comprehensive enough to incorporate both longterm directional change and short-term cyclic forest dynamics,as well as transitions from one dynamics mode to another depending on changes in the driving disturbance regime type.Models that capture such essential features of forest dynamics are indispensable for educational purposes,in setting reference conditions and in developing methods in forest conservation,restoration and ecosystem management.
