Individual tree health plays a vital role in maintaining a forest's ecological functions,including resources for waterfowl and other wildlife.Seasonal flooding due to altered hydrology is a major stressor on indiv...Individual tree health plays a vital role in maintaining a forest's ecological functions,including resources for waterfowl and other wildlife.Seasonal flooding due to altered hydrology is a major stressor on individual tree health in Greentree reservoirs(GTR),impounded bottomland hardwood forests especially less water tolerant species like red oaks(Quercus spp.).We evaluated the health of individual red oak species(n=6,432)in 662 plots across elevation gradients in 12 GTRs within the lower Mississippi Alluvial Valley using two tree health assessment approaches.The first approach assigns tree conditions(i.e.,stressed,moderate,low)based on overall qualitative tree attributes,while the second approach ranks stress,assigning numerical value based on the severity of four distinct qualitative tree attributes(i.e.,tip dieback,epicormics branch,bark condition,basal swell).The result indicated that the highest mean stress rank and the highest proportion of stressed tree conditions were red oak species,nuttall oak(Q.texana;18.59,0.44),willow oak(Q.phellos;18.66,0.38)and cherrybark oak(Q.pagoda;18.90,0.37).Red oak stress is positively correlated to elevation across the landscape(τ=0.10,p<0.001),but is negatively correlated to relative elevation,topographical changes,within each GTR(τ=-0.11,p<0.001).Additionally,the two health assessments are significantly associated(χ^(2)=313.78,df=2,p<0.001)and had a 13.1%misclassification rate.By utilizing the stress rank method for better classification of tree conditions to understand the adverse effect of prolonged flooding on the health of desirable red oak and other native tree species,management practices can be adjusted to improve tree health in GTRs,benefiting both wildlife and economic value.展开更多
Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpou...Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.展开更多
基金Five Oaks Ag Research&Education Center(DS18849)the University of Arkansas Division of Agriculture(PR02276)funding was provided by the U.S.Department of Agriculture,the National Institute of Food and Agriculture,and the McIntire-Stennis Capacity Grant(2729 YR21-25 and ARK02594).
文摘Individual tree health plays a vital role in maintaining a forest's ecological functions,including resources for waterfowl and other wildlife.Seasonal flooding due to altered hydrology is a major stressor on individual tree health in Greentree reservoirs(GTR),impounded bottomland hardwood forests especially less water tolerant species like red oaks(Quercus spp.).We evaluated the health of individual red oak species(n=6,432)in 662 plots across elevation gradients in 12 GTRs within the lower Mississippi Alluvial Valley using two tree health assessment approaches.The first approach assigns tree conditions(i.e.,stressed,moderate,low)based on overall qualitative tree attributes,while the second approach ranks stress,assigning numerical value based on the severity of four distinct qualitative tree attributes(i.e.,tip dieback,epicormics branch,bark condition,basal swell).The result indicated that the highest mean stress rank and the highest proportion of stressed tree conditions were red oak species,nuttall oak(Q.texana;18.59,0.44),willow oak(Q.phellos;18.66,0.38)and cherrybark oak(Q.pagoda;18.90,0.37).Red oak stress is positively correlated to elevation across the landscape(τ=0.10,p<0.001),but is negatively correlated to relative elevation,topographical changes,within each GTR(τ=-0.11,p<0.001).Additionally,the two health assessments are significantly associated(χ^(2)=313.78,df=2,p<0.001)and had a 13.1%misclassification rate.By utilizing the stress rank method for better classification of tree conditions to understand the adverse effect of prolonged flooding on the health of desirable red oak and other native tree species,management practices can be adjusted to improve tree health in GTRs,benefiting both wildlife and economic value.
基金Financial and logistic support for this research was provided by Five Oaks Ag Research&Education Center(DS18849)University of Arkansas Division of Agriculture(PR02276)University of Arkansas at Monticello.Funding support was provided by U.S.Department of Agriculture,National Institute of Food and Agriculture,McIntire-Stennis Capacity Grant(2729 YR21-25 and ARK02594).
文摘Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.
