Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,...Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.展开更多
Subri River Forest Reserve(SR)is the most extensive forest area in Ghana with an accompanying rich floral species.Over the years,logging from both legally prescribed and illegal operations remain the predominant fores...Subri River Forest Reserve(SR)is the most extensive forest area in Ghana with an accompanying rich floral species.Over the years,logging from both legally prescribed and illegal operations remain the predominant forest disturbance in SR.Gap creation following logging is crucial in determining tree species composition and diversity.Hence,the study evaluated the composition and diversity of naturally regenerated tree species in logging gaps of different sizes and,again examined the roles of these tree species in fulfilling the economic and ecological agenda of sustainable forest management after logging in SR.Twelve gaps were randomly selected:4 each were grouped into small size(≤200 m^(2)),medium size(201–300 m^(2)),and large size(≥300 m^(2)).Data were gathered from 1 m^(2) circular area at gap centres and repeatedly inside 1 m width strip along 20 m individual N-S-E-W transects.Species diversity differed significantly between gap sizes.Higher diversity indices were measured in large size gaps.Gap sizes shared similar species.There were significant differences among various height groupings of tree species across all three gap sizes.Pioneers preferred medium to large size gaps,while shadetolerant tree species preferred small size gaps for their abundance.Vulnerable and Lower Risk Near Threatened tree species under Conservation Status and,Premium and Commercial tree species under Utilisation Status preferred small size gaps for their proliferation and conservation.Therefore,we recommend the single tree-based selective logging for ensuring creations of small to medium size(200–300 m^(2))gaps through adjustments to the logging permit process,revision of Allocation Quota Permit,strict adherence to the 40-year polycyclic selection system,along with more dedicated enforcement and monitoring.Changes along these protocols would tremendously facilitate natural regeneration of different suites of timber species resulting in the improvement of the overall biodiversity conservation associated with the forest,more sustainable forest harvests and more income to those who receive permits.展开更多
The limited number of studies on mixed plantations makes it difficult to accurately predict success of mixed-species combination especially with regards to growth, undergrowth diversity and carbon sequestration potent...The limited number of studies on mixed plantations makes it difficult to accurately predict success of mixed-species combination especially with regards to growth, undergrowth diversity and carbon sequestration potentials. This study therefore provides information on the effects of Ceiba pentandra, Terminalia superba, Cedrela odorata and Khaya anthotheca in three different stand combinations on growth, undergrowth diversity and carbon sequestration potential. A 15-year-old coupe of 32 ha of mixed tree species stand combinations was selected for the study. The coupe was stratified based on the species combinations. Nested sub-plots (25 m × 25 m) were randomly laid in different species stand combinations for growth data collection. In each nested sub-plot, 1 m × 1 m plots were also randomly laid for undergrowth diversity study. The results revealed that two species stand combination of Ceiba pentandra and Terminalia superba performed better in terms of growth, carbon sequestration and carbon content as compared to the other species stand combinations. The saplings on the other hand, were more diverse under the three species stand combination plots. Also, the effective number of species, species richness, evenness, and dominance were higher in the four species stand combination plots. Generally, Ceiba pentandra and Terminalia superba are compatible as it produced the highest growth and carbon sequestration potential.展开更多
Thinning is a necessary and complex forestry activity.The complexity increases due to theoretical disagreements,contradictory recommendations,and errors of modern practice,which require confirmation through longtime e...Thinning is a necessary and complex forestry activity.The complexity increases due to theoretical disagreements,contradictory recommendations,and errors of modern practice,which require confirmation through longtime experiments.This article presents a summary of experimental results from plantations established 20–30 years ago and explains concepts of the theory,methods,and regime of thinning in permanent sample plots of pine stands in Gatchinsky forest of the Leningrad region.The research results allow for the clarification of growth patterns and age dynamics of pine stands subject to heavy,low thinning,as well as the results of applying the crown(high)thinning technique and a mixed treatment.A combined thinning and fertilization could improve wood quality and yield compared to conventional methods.Of particular scientific importance is the analysis of change in tree diameter classes during growth and after thinning.The research results allow for optimizing the treatment regime in pine plantations and reducing labor intensity by increasing the intensity of thinning and reducing the number of techniques.展开更多
文摘Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.
基金funded by the Internal Grant Agency of Mendel University in Brno(LDF_VP_2019015)the Framework of Bilateral Mobility Program for Traineeship of Doctoral Students,MENDELU。
文摘Subri River Forest Reserve(SR)is the most extensive forest area in Ghana with an accompanying rich floral species.Over the years,logging from both legally prescribed and illegal operations remain the predominant forest disturbance in SR.Gap creation following logging is crucial in determining tree species composition and diversity.Hence,the study evaluated the composition and diversity of naturally regenerated tree species in logging gaps of different sizes and,again examined the roles of these tree species in fulfilling the economic and ecological agenda of sustainable forest management after logging in SR.Twelve gaps were randomly selected:4 each were grouped into small size(≤200 m^(2)),medium size(201–300 m^(2)),and large size(≥300 m^(2)).Data were gathered from 1 m^(2) circular area at gap centres and repeatedly inside 1 m width strip along 20 m individual N-S-E-W transects.Species diversity differed significantly between gap sizes.Higher diversity indices were measured in large size gaps.Gap sizes shared similar species.There were significant differences among various height groupings of tree species across all three gap sizes.Pioneers preferred medium to large size gaps,while shadetolerant tree species preferred small size gaps for their abundance.Vulnerable and Lower Risk Near Threatened tree species under Conservation Status and,Premium and Commercial tree species under Utilisation Status preferred small size gaps for their proliferation and conservation.Therefore,we recommend the single tree-based selective logging for ensuring creations of small to medium size(200–300 m^(2))gaps through adjustments to the logging permit process,revision of Allocation Quota Permit,strict adherence to the 40-year polycyclic selection system,along with more dedicated enforcement and monitoring.Changes along these protocols would tremendously facilitate natural regeneration of different suites of timber species resulting in the improvement of the overall biodiversity conservation associated with the forest,more sustainable forest harvests and more income to those who receive permits.
文摘The limited number of studies on mixed plantations makes it difficult to accurately predict success of mixed-species combination especially with regards to growth, undergrowth diversity and carbon sequestration potentials. This study therefore provides information on the effects of Ceiba pentandra, Terminalia superba, Cedrela odorata and Khaya anthotheca in three different stand combinations on growth, undergrowth diversity and carbon sequestration potential. A 15-year-old coupe of 32 ha of mixed tree species stand combinations was selected for the study. The coupe was stratified based on the species combinations. Nested sub-plots (25 m × 25 m) were randomly laid in different species stand combinations for growth data collection. In each nested sub-plot, 1 m × 1 m plots were also randomly laid for undergrowth diversity study. The results revealed that two species stand combination of Ceiba pentandra and Terminalia superba performed better in terms of growth, carbon sequestration and carbon content as compared to the other species stand combinations. The saplings on the other hand, were more diverse under the three species stand combination plots. Also, the effective number of species, species richness, evenness, and dominance were higher in the four species stand combination plots. Generally, Ceiba pentandra and Terminalia superba are compatible as it produced the highest growth and carbon sequestration potential.
文摘Thinning is a necessary and complex forestry activity.The complexity increases due to theoretical disagreements,contradictory recommendations,and errors of modern practice,which require confirmation through longtime experiments.This article presents a summary of experimental results from plantations established 20–30 years ago and explains concepts of the theory,methods,and regime of thinning in permanent sample plots of pine stands in Gatchinsky forest of the Leningrad region.The research results allow for the clarification of growth patterns and age dynamics of pine stands subject to heavy,low thinning,as well as the results of applying the crown(high)thinning technique and a mixed treatment.A combined thinning and fertilization could improve wood quality and yield compared to conventional methods.Of particular scientific importance is the analysis of change in tree diameter classes during growth and after thinning.The research results allow for optimizing the treatment regime in pine plantations and reducing labor intensity by increasing the intensity of thinning and reducing the number of techniques.
