Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the b...Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the biological attributes of tropical species may affect competitive outcomes under varying resource conditions.We collected and analysed a 10-year dataset of radial growth rates in canopy trees from a network of forest inventory plots located in divergent forest types over an extensive meteorological gradient in Ghana,West Africa.We used nonlinear models to estimate the relative reduction in potential growth(basal area increment)of individual target trees of a given species as a consequence of the combined effects of(1)target tree size,(2)variation in crowding levels by neighbouring trees,(3)the functional attributes of those neighbours(wood density and shade tolerance),and(4)local soil moisture levels.Analyses were conducted separately for the 15 most common species in the inventory network.In opposition to neutral theory,our findings indicate that the strength of interactions among competing species was distinctly asymmetric and dynamic.Wood density was an important characteristic that modified competitive outcomes for most species,particularly under varying levels of resource availability.Specifically,dense wood was an attribute that conferred comparatively stronger competitive ability in moisture-limited conditions.Larger individuals were notably less sensitive to the effects of moisture-dependent competition.Our results suggest that attributes such as wood density may reflect divergent life history strategies that differentiate species’fitness and competitive ability in varying environments.The dynamic nature of competition,influenced by a complex interplay of biological and abiotic factors,implies that more prevalent dry periods,which have been forecast for tropical Africa,may impact the physiognomy and function of future forest communities in the region.展开更多
Studies on the relationship between moisture behavior and gaseous VOCs （Volatile Organic Compounds） removal efficiency of packed tower biofilters are limited. In this research, the nutrient holding capacity, moist...Studies on the relationship between moisture behavior and gaseous VOCs （Volatile Organic Compounds） removal efficiency of packed tower biofilters are limited. In this research, the nutrient holding capacity, moisture evaporation rate and gaseous toluene and MEK （Methyl Ethyl Ketone） removal efficiencies of bioreactors with porous synthetic resin as the packing material were simultaneously observed. The nutrient holding capacity in one of the reactors was higher than those of the other two because its packing layer was frequently supplied with a nutrient solution by soaking. This reactor exhibited the highest toluene removal efficiency. However, excessive biomass growth was observed in this reactor. The reactor with a less frequent supply of nutrient solution by soaking showed a slightly lower toluene removal efficiency, possibly due to lack of nutrients in the packing layer. The reactor that was fed with the nutrient solution by spraying it onto the packing layer （a common method for supplying moisture） had the lowest toluene removal efficiency, mainly because of the uneven distribution of nutrients. Moreover, the moisture evaporation rate in the packing layer during moisture supply and heat balance were determined.展开更多
基金We express our gratitude to the Internal Grant Agency of the Faculty of Forestry and Wood Sciences,Czech University of Life Sciences,Prague(Grant No.IGA A_24_24)the Ministry of Education,Youth and Sports of the Czech Republic(Grant INTER-TRANSFER No.LTT20017)for funding this study.
文摘Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the biological attributes of tropical species may affect competitive outcomes under varying resource conditions.We collected and analysed a 10-year dataset of radial growth rates in canopy trees from a network of forest inventory plots located in divergent forest types over an extensive meteorological gradient in Ghana,West Africa.We used nonlinear models to estimate the relative reduction in potential growth(basal area increment)of individual target trees of a given species as a consequence of the combined effects of(1)target tree size,(2)variation in crowding levels by neighbouring trees,(3)the functional attributes of those neighbours(wood density and shade tolerance),and(4)local soil moisture levels.Analyses were conducted separately for the 15 most common species in the inventory network.In opposition to neutral theory,our findings indicate that the strength of interactions among competing species was distinctly asymmetric and dynamic.Wood density was an important characteristic that modified competitive outcomes for most species,particularly under varying levels of resource availability.Specifically,dense wood was an attribute that conferred comparatively stronger competitive ability in moisture-limited conditions.Larger individuals were notably less sensitive to the effects of moisture-dependent competition.Our results suggest that attributes such as wood density may reflect divergent life history strategies that differentiate species’fitness and competitive ability in varying environments.The dynamic nature of competition,influenced by a complex interplay of biological and abiotic factors,implies that more prevalent dry periods,which have been forecast for tropical Africa,may impact the physiognomy and function of future forest communities in the region.
文摘Studies on the relationship between moisture behavior and gaseous VOCs （Volatile Organic Compounds） removal efficiency of packed tower biofilters are limited. In this research, the nutrient holding capacity, moisture evaporation rate and gaseous toluene and MEK （Methyl Ethyl Ketone） removal efficiencies of bioreactors with porous synthetic resin as the packing material were simultaneously observed. The nutrient holding capacity in one of the reactors was higher than those of the other two because its packing layer was frequently supplied with a nutrient solution by soaking. This reactor exhibited the highest toluene removal efficiency. However, excessive biomass growth was observed in this reactor. The reactor with a less frequent supply of nutrient solution by soaking showed a slightly lower toluene removal efficiency, possibly due to lack of nutrients in the packing layer. The reactor that was fed with the nutrient solution by spraying it onto the packing layer （a common method for supplying moisture） had the lowest toluene removal efficiency, mainly because of the uneven distribution of nutrients. Moreover, the moisture evaporation rate in the packing layer during moisture supply and heat balance were determined.
