Quercus L.has significant societal,ecological and economic benefits in the Northern Hemisphere.However,species identification among oaks is notoriously difficult.China harbours highly diverse oaks,of which the diversi...Quercus L.has significant societal,ecological and economic benefits in the Northern Hemisphere.However,species identification among oaks is notoriously difficult.China harbours highly diverse oaks,of which the diversity of white oaks is the most extensive;however,to date,the evolution of chloroplast(cp)genomes in white oaks in China has not been comprehensively studied.Thus,we sequenced the complete cp genomes(161,254 bp,161,229 bp and 161,254 bp in size)of three white oak species(Quercus serrata Thunb.var.brevipetiolata A.DC.Nakai,Quercus wutaishansea Mary and Quercus mongolica Fischer ex Ledebour,respectively).Six white oak species(Quercus aliena Blume,Quercus dentata Thunb.,Quercus aliena Blume var.acutiserrata Maximowicz ex Wenzig,Q.serrata var.brevipetiolata,Q.wutaishanica and Q.mongolica)and five other Fagaceae species(Quercus rubra L.,Quercus variabilis Bl.,Quercus aquifolioid.es Rehd.et Wils.,Fagus engleriana Seem.and Castanea henryi Skan Rehd.et Wils.)were retrieved for comparative analyses.We detected11 highly divergent regions(psbA,matK/rps16,rps16,trnSGCU/trnG-GCC,trnR-UCU/atpA,trnT-GGU/psbD,ndhJ,ndhJ/ndhK,accD,ndhF and ycfl)through comparative analyses and these regions might be used as molecular markers.Theωratio of the rps12,rpoC2 and ycf1 genes was greater than 1 in several comparison groups between white oaks and the petA gene was subjected to significant positive selection between the comparison of six white oaks and Q.variabilis.Phylogenetic analyses revealed that six white oaks were grouped with Q.rubra,forming a single clade.展开更多
Robert Penn Warren(1905-1989) is one of twentieth-century America's most distinguished men of letters.Honored with three Pulitzer Prizes,Warren is the only writer who has been a Pulitzer Prize winner in two differ...Robert Penn Warren(1905-1989) is one of twentieth-century America's most distinguished men of letters.Honored with three Pulitzer Prizes,Warren is the only writer who has been a Pulitzer Prize winner in two different genres-poetry and fiction.In 1986,Warren was crowned as the first American Poet Laureate.Though he is a Renaissance man of letters in many genres,the central thrust of Warren's literary career lies in the field of poetry.Love and knowledge are the two themes which penetrate his sixty years' poetic career.Based on textual analysis,applying the method of close reading,the present study intends to explore the sound patterning,metaphor,tension and the technical devices which reinforce the theme of love and knowledge in the poem of the Bearded Oaks.展开更多
This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their mat...This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers.Based on a preliminary study of leaf morphological traits,the individuals separated into six groups.The studied halfsib oak families were also compared for allelic diversity,including group variations;genotypic structure;genetic diversity;and the degree of genetic subdivision and diff erentiation.The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species.Genotypic analysis of the half-sibling off spring showed the asymmetric nature of interspecifi c hybridization processes of pedunculate and sessile oaks in mixed stands.展开更多
There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation...There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation. The close relationship between the flora of Ussuli—Amur region and Japan is discussed. Analyses of heat and energy balance, and biomass of mongolian oak forests arc provided. Many measurements indicate that, in a nonclosed stand, the wood production of a stand is positively correlated with leaf area index (LAI).展开更多
Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermen...Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermented in two types of fermenters(stainless steel tank and rotated oak barrel)and aged in six types of oak barrels(three geographic origins×two toasting degrees)for different time(0,3,6 and 9 months,respectively).Results showed that 30 volatiles were associated with barrels and increased during oak aging.The fermenters could influence the intensities of the toast,leathery,smoky,fruity,floral and caramel aromas.The concentration of whisky lactone,eugenol,cis-isoeugenol,and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels.The concentrations of guaiacol,syringol,trans-isoeugenol,furfural alcohol,vanilla,cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones.The compounds originating from the barrels could be used to distinguish the types of different barrels,but the other general grape-derived and fermentation-derived volatiles could not.The fermenters,oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged‘Merlot’dry red wines,but the influence of the geographic origin was not obvious.展开更多
Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near futur...Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near future is high,yet knowledge of its predicted effects is limited.Our study utilized the biomod2 R package to develop habi-tat suitability ensemble models based on bioclimatic and topographic environmental variables and the known loca-tions of current distribution of Q.arkansana.We predicted suitable habitats across three climate change scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5)for 2050,2070,and 2090.Our findings reveal that the current suitable habitat for Q.arkansana is approximately 127,881 km^(2) across seven states(Texas,Arkansas,Alabama,Louisiana,Mississippi,Georgia,and Florida);approximately 9.5%is encompassed within state and federally managed protected areas.Our models predict that all current suitable habitats will disap-pear by 2050 due to climate change,resulting in a northward shift into new regions such as Tennessee and Kentucky.The large extent of suitable habitat outside protected areas sug-gests that a species-specific action plan incorporating pro-tected areas and other areas may be crucial for its conserva-tion.Moreover,protection of Q.arkansana habitat against climate change may require locally and regionally focused conservation policies,adaptive management strategies,and educational outreach among local people.展开更多
Background:The Iberian Peninsula comprises one of the largest boundaries between Mediterranean and Eurosiberian vegetation,known as sub-Mediterranean zone.This ecotone hosts many unique plant species and communities a...Background:The Iberian Peninsula comprises one of the largest boundaries between Mediterranean and Eurosiberian vegetation,known as sub-Mediterranean zone.This ecotone hosts many unique plant species and communities and constitutes the low-latitude(warm)margin of numerous central European species which co-occur with Mediterranean vegetation.Two of the main species found in this region are the Eurosiberian European beech(Fagus sylvatica L.)and the Mediterranean Pyrenean oak(Quercus pyrenaica Willd.).It remains unclear how the different physiological and adaptive strategies of these two species reflect their niche partitioning within a subMediterranean community and to what extent phenotypic variation(intraspecific variability)is driving niche partitioning across Eurosiberian and Mediterranean species.Methods:We quantified functional niche partitioning,based on the n-dimensional hypervolume to nine traits related to resource acquisition strategies(leaf,stem and root)plus relative growth rate as an additional wholeplant trait,and the environmental niche similarity between Pyrenean oak and European beech.Further,we analyzed the degree of phenotypic variation of both target species and its relationship with relative growth rates(RGR)and environmental conditions.Plant recruitment was measured for both target species as a proxy for the average fitness.Results:Species’functional space was highly segregated(13.09%overlap),mainly due to differences in niche breadth(59.7%)rather than niche replacement(25.6%),and beech showed higher trait variability,i.e.,had larger functional space.However,both species shared the environmental space,i.e.,environmental niches were overlapped.Most plant traits were not related to abiotic variables or RGR,neither did RGR to plant traits.Conclusions:Both target species share similar environmental space,however,show notably different functional resource-use strategies,promoting a high complementarity that contributes to maintaining a high functionality in sub-Mediterranean ecosystems.Therefore,we propose that conservation efforts be oriented to preserve both species in these habitats to maximize ecosystem functionality and resilience.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
Ice storms,as important sources of frequent and injurious disturbances,drive forest dynamics in the Northern Hemisphere.However,stand-level differential vulnerability to ice storms and the associated factors that pred...Ice storms,as important sources of frequent and injurious disturbances,drive forest dynamics in the Northern Hemisphere.However,stand-level differential vulnerability to ice storms and the associated factors that predispose forest stands remain unclear.This is particularly concerning in the subtropics where the frequency of ice storms is predicted to increase with global warming.Here we assessed how the impact on three forest stands(early and late secondary-growth forests,and old-growth forests)differed after an extreme ice storm during 20–21 March 2022,and identified the abiotic and biotic factors that determine the damage intensity in the Shennongjia World Natural Heritage Site,a biodiversity conservation hotspot in central China.We found a stand-specific‘middomain effect’where the late secondary-growth forest sustained the most severe damage,the early secondarygrowth forest sustained the least,and the old-growth forest suffered an intermediate amount.‘Crown broken’was the most severe damage type across all three forest stands,although the proportion of‘branch broken’was also high in the old-growth forest.Topography played a significant role in determining the vulnerability of the early secondary-growth forest to severe ice storms whereas the forest structure and composition were important factors in explaining the damage rates in the old-growth forest,although they differed among the damage categories.In contrast,topography,forest structure and composition generally explain the intensity of damage in the late secondary-growth forests.Our results highlight that,in subtropical forests,the intensity of damage caused by severe ice storms and related determining factors are stand-level dependent.We also suggest exploring potential management strategies(e.g.,slow-growing hardwood species that can resist storms should be the main species for reforestation in early secondary-growth forests)to mitigate the risk of future severe ice storms,as well as other wind-related climatic extremes.展开更多
We analyzed national forest inventory data collected from circa 2000–2018 across 37 states in the eastern United States to better understand the influence of forest health related canopy disturbances on the regenerat...We analyzed national forest inventory data collected from circa 2000–2018 across 37 states in the eastern United States to better understand the influence of forest health related canopy disturbances on the regeneration and recruitment dynamics of upland oaks(Quercus).We found low levels of oak recruitment across all disturbance types examined but limited evidence of any direct effects from the type of disturbance on the population of regenerating oaks.The general lack of differences in oak regeneration response between forest health disturbances and disturbances caused by harvested or non-disturbed plots does not indicate that the effects of forest health disturbances were benign,however.Instead,low level of oak recruitment across all disturbance types highlights the pervasiveness of the trend of shifting composition in once oak-dominated forests where oak is absent or sparse in the regeneration layer.Our results show that oak recruitment was higher when oak was present as advance reproduction prior to disturbance from any cause examined.Collectively,these results lead us to conclude that the widespread inadequacy of oak advance reproduction in mature oak-dominated forests is the prevailing threat to oak forest health and sustainability.We suggest the status of advance reproduction be treated as a co-morbidity when weighing the risk and potential outcomes from other threats to upland oak forests in the eastern United States.展开更多
The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor und...The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor underpinning the low vitality of West-European forests.Selecting tree species with soil ameliorative traits is proposed as an avenue to counteract soil acidification and improve overall forest vitality.Here we evaluate the impact of black cherry(Prunus serotina Ehrh.),a known rich litter species,on the vitality of neighboring pedunculate oak(Quercus robur L.)in ten mixed forests on sand in Germany,Belgium and the Netherlands.We found that black cherry admixture increases foliar N and P to a surplus whereas it causes deficiencies in foliar Mg,thereby resulting in an overall negative effect on oak foliar nutrient concentrations.Contrary,defoliation of oak leaves by herbivory decreases with the proximity of black cherry.Using structural equation modelling(SEM),we tested the hypothesized‘improved soil health’pathway.Our analyses showed that black cherry admixture leads to lower accumulation in the humus layer,resulting in higher soil base saturation which has a positive effect on foliar Ca yet a negative effect on total chlorophyll.Moreover,the SEM illustrated that herbivory of oak leaves decreases when black cherry is admixed,both via dilution and improved soil health.Indirect effects of black cherry on oak vitality via“improved soil health”in our SEM are however small in comparison to direct relations.Hence,our study showed that the combined positive and negative impacts of black cherry on oak vitality are limited,which tempers the potential benefits of using the rich litter species to counteract oak decline via improved soil health–yet,the concern of black cherry as an invasive alien species negatively affecting the vitality of mature pedunculate oak trees may also be exaggerated.展开更多
There are two well-known types of tree pruning, crown raising and crown reduction. In Japan, the former has been rarely used, whereas the latter has been widely used. However, it remains unclear which type is more eff...There are two well-known types of tree pruning, crown raising and crown reduction. In Japan, the former has been rarely used, whereas the latter has been widely used. However, it remains unclear which type is more effective to maintain tree vigor and health. Bamboo-leaf oak (Quercus myrsinifolia) trees were experimentally planted and pruned with the two pruning types compared with the no-pruning type. In the crown raising, the lower part of each tree was pruned, and its dominant leader was maintained from the aspect of structural pruning, whereas in the crown reduction, the upper part of each tree was pruned, and the tree height was reduced. The oak trees were observed and recorded in terms of leaf area, leaf weight, branch weight, and tree shape for about one year. The morphological data were statistically analyzed in terms of their allometric relationships. The crown raising type shared the same allometric patterns with the no-pruning types, but the crown reduction type did not. The trees of the crown reduction type were more likely to suffer from pests and disease. The allometric differences between the two pruning types may be considered the result of a decline in whole-tree vigor and health in crown reduction. The crown raising seemed more likely to control tree vigor and health than the crown reduction. The present results would help arborists determine which method to use for pruning.展开更多
Cork oak in Maamora forest is experiencing the dieback phenomenon. The evaluation of the latter in this forest has gained the importance over time and with the solicitation of managers to objectify its phytosanitary s...Cork oak in Maamora forest is experiencing the dieback phenomenon. The evaluation of the latter in this forest has gained the importance over time and with the solicitation of managers to objectify its phytosanitary situation. Aiming at prioritizing management actions, remote sensing seems to be an effective tool to inquire about stands’ health conditions and their evolution. To this end, this study aims at mapping and validating health status of cork oak stands in Maamora. Sentinel 2 images in 2015 and 2020 were processed to calculate the differential normalized difference water index (NDWI), revealing vegetation moisture variation caused by drought. A statistical method based on thresholds was used to map cork oak dieback stands, those with no changes and those recovered. Results have shown that 54.63% of cork oak in Maamora forest have not changed in terms of phytosanitary situation between 2015 and 2020, 31.10% of oak stands are afflicted by a slight decline and 12.97% by a severe decline. Areas with slight or strong recovery remain minimal and represent 1.04% and 0.25% respectively. Ground data indicated that the map generated displayed a good distinction between stands severely and slightly declined with a global accuracy of 66.66%. Therefore, further research elaborating an advanced vegetation index reflecting the various factors of dieback would be of much importance.展开更多
Afforestation has been observed as a green trend in urban areas. The incorporation of trees in urban infrastructure is highly recommended to act as a solution to outlined environmental problems such as global warming....Afforestation has been observed as a green trend in urban areas. The incorporation of trees in urban infrastructure is highly recommended to act as a solution to outlined environmental problems such as global warming. However, it has been precipitously introduced in cities, towns, and metropolitans. The introduction of the green practice was so abrupt that it became devoid to meeting the essential needs for tree growth, thus, failing to bring out the desired effects. Inappropriately selecting and planting trees in urban spaces has resulted in stressed trees that are deficient at reaching up to the calculated goals and in the long run end up being problematic. The main objective of this study is to evaluate the implications of planting southern live oak (Quercus virginiana) trees in the wrong urban space so as to aid in recommending sustainable green solutions for the urban community. By studying southern live oaks planted in Howell Community Park and three randomly selected areas in Southern University Baton Rouge Campus, this study analyzes how the selection of these tree species in the urban spaces influenced their growth and general well-being. These urban spaces were randomly drafted based on accessibility and availability of several southern live oaks. Planting approaches in the four study areas were explored and the general health condition of the trees was determined using the tree appraisal method presented by the i-tree model: my tree. ArcGIS collector was used to collect the GPS coordinates of the trees and ArcMap was used to generate the maps of the study areas. ArcMap software geolocated the coordinates of the southern live oaks in all the four-study areas. The software was used to generate shapefiles of the four study areas and their location in East Baton Rouge. The analysis of the results proved that none of the southern live oaks had an excellent health condition and most of the trees experienced different issues due to planting them in the wrong urban spaces.展开更多
采用激光粒度分析法测定超细 OAK 木炭及竹炭粉粒度,探讨了分散剂种类、分散时间、搅拌速度、超声时间等因素对超细 OAK 木炭及竹炭粉粒度的影响。结果表明:以六偏磷酸钠为分散剂时分散效果最佳,其用量为0.06g/(100mlOAK 木炭及竹炭粉乳...采用激光粒度分析法测定超细 OAK 木炭及竹炭粉粒度,探讨了分散剂种类、分散时间、搅拌速度、超声时间等因素对超细 OAK 木炭及竹炭粉粒度的影响。结果表明:以六偏磷酸钠为分散剂时分散效果最佳,其用量为0.06g/(100mlOAK 木炭及竹炭粉乳液);在测定时选择循环搅拌泵速为2200~2400r/min 较好;超声时间为200s 左右时,可达到最佳分散效果。展开更多
Pre- and post-defoliation radial growth rates were used to examine the effects of silvicultural thinning and two consecutive years of gypsy moth (Lymantria dispar L.) defoliation on Quercus spp. wood volume production...Pre- and post-defoliation radial growth rates were used to examine the effects of silvicultural thinning and two consecutive years of gypsy moth (Lymantria dispar L.) defoliation on Quercus spp. wood volume production. In the first phase of the study, tree rings from 65 dissected stems, were used to develop polynomial models to estimate annual cumulative volume (m3) increment for the entire merchantable stem, as a function of dbh (tree diameter at 1.37 m above the ground). In Phase II of the study, 81 additional trees were sampled using only increment cores. Cumulative diameter increments from the cores were used in the polynomial models to compare tree volume growth changes during and after defoliation among the thinning treatments. Even though there was no significant difference in estimated volume lost during defoliation among treatments, post-defoliation growth was enhanced by thinning. Total volume reduction from defoliation ranged from 28,049 (±17,462) cm3 to 25,993 (±16,251) cm3 per tree. The stand receiving the thinning treatment with the lowest residual stocking produced significantly more volume (P = 0.002) after defoliation than the other treatments.展开更多
基金the Fundamental Research Funds for the Central Non-Profit Research Institution of CAF(CAFYBB2018ZB001)the National Natural Science Foundation of China(42071065)。
文摘Quercus L.has significant societal,ecological and economic benefits in the Northern Hemisphere.However,species identification among oaks is notoriously difficult.China harbours highly diverse oaks,of which the diversity of white oaks is the most extensive;however,to date,the evolution of chloroplast(cp)genomes in white oaks in China has not been comprehensively studied.Thus,we sequenced the complete cp genomes(161,254 bp,161,229 bp and 161,254 bp in size)of three white oak species(Quercus serrata Thunb.var.brevipetiolata A.DC.Nakai,Quercus wutaishansea Mary and Quercus mongolica Fischer ex Ledebour,respectively).Six white oak species(Quercus aliena Blume,Quercus dentata Thunb.,Quercus aliena Blume var.acutiserrata Maximowicz ex Wenzig,Q.serrata var.brevipetiolata,Q.wutaishanica and Q.mongolica)and five other Fagaceae species(Quercus rubra L.,Quercus variabilis Bl.,Quercus aquifolioid.es Rehd.et Wils.,Fagus engleriana Seem.and Castanea henryi Skan Rehd.et Wils.)were retrieved for comparative analyses.We detected11 highly divergent regions(psbA,matK/rps16,rps16,trnSGCU/trnG-GCC,trnR-UCU/atpA,trnT-GGU/psbD,ndhJ,ndhJ/ndhK,accD,ndhF and ycfl)through comparative analyses and these regions might be used as molecular markers.Theωratio of the rps12,rpoC2 and ycf1 genes was greater than 1 in several comparison groups between white oaks and the petA gene was subjected to significant positive selection between the comparison of six white oaks and Q.variabilis.Phylogenetic analyses revealed that six white oaks were grouped with Q.rubra,forming a single clade.
文摘Robert Penn Warren(1905-1989) is one of twentieth-century America's most distinguished men of letters.Honored with three Pulitzer Prizes,Warren is the only writer who has been a Pulitzer Prize winner in two different genres-poetry and fiction.In 1986,Warren was crowned as the first American Poet Laureate.Though he is a Renaissance man of letters in many genres,the central thrust of Warren's literary career lies in the field of poetry.Love and knowledge are the two themes which penetrate his sixty years' poetic career.Based on textual analysis,applying the method of close reading,the present study intends to explore the sound patterning,metaphor,tension and the technical devices which reinforce the theme of love and knowledge in the poem of the Bearded Oaks.
基金partly supported by the long-term research programme Sustainable Forestry and Global Changes implemented by the Lithuanian Research Centre for Agriculture and Forestry
文摘This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers.Based on a preliminary study of leaf morphological traits,the individuals separated into six groups.The studied halfsib oak families were also compared for allelic diversity,including group variations;genotypic structure;genetic diversity;and the degree of genetic subdivision and diff erentiation.The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species.Genotypic analysis of the half-sibling off spring showed the asymmetric nature of interspecifi c hybridization processes of pedunculate and sessile oaks in mixed stands.
文摘There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation. The close relationship between the flora of Ussuli—Amur region and Japan is discussed. Analyses of heat and energy balance, and biomass of mongolian oak forests arc provided. Many measurements indicate that, in a nonclosed stand, the wood production of a stand is positively correlated with leaf area index (LAI).
基金the financial support received from The Key Project of R&D Program of Ningxia Hui Autonomous Region,China(2022BBF01003)China Agriculture Research System of MOF and MARA(CARS-29).
文摘Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermented in two types of fermenters(stainless steel tank and rotated oak barrel)and aged in six types of oak barrels(three geographic origins×two toasting degrees)for different time(0,3,6 and 9 months,respectively).Results showed that 30 volatiles were associated with barrels and increased during oak aging.The fermenters could influence the intensities of the toast,leathery,smoky,fruity,floral and caramel aromas.The concentration of whisky lactone,eugenol,cis-isoeugenol,and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels.The concentrations of guaiacol,syringol,trans-isoeugenol,furfural alcohol,vanilla,cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones.The compounds originating from the barrels could be used to distinguish the types of different barrels,but the other general grape-derived and fermentation-derived volatiles could not.The fermenters,oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged‘Merlot’dry red wines,but the influence of the geographic origin was not obvious.
基金The work was partially supported by research project funding from the Undergraduate Research Grant,Arkansas Tech University.
文摘Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near future is high,yet knowledge of its predicted effects is limited.Our study utilized the biomod2 R package to develop habi-tat suitability ensemble models based on bioclimatic and topographic environmental variables and the known loca-tions of current distribution of Q.arkansana.We predicted suitable habitats across three climate change scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5)for 2050,2070,and 2090.Our findings reveal that the current suitable habitat for Q.arkansana is approximately 127,881 km^(2) across seven states(Texas,Arkansas,Alabama,Louisiana,Mississippi,Georgia,and Florida);approximately 9.5%is encompassed within state and federally managed protected areas.Our models predict that all current suitable habitats will disap-pear by 2050 due to climate change,resulting in a northward shift into new regions such as Tennessee and Kentucky.The large extent of suitable habitat outside protected areas sug-gests that a species-specific action plan incorporating pro-tected areas and other areas may be crucial for its conserva-tion.Moreover,protection of Q.arkansana habitat against climate change may require locally and regionally focused conservation policies,adaptive management strategies,and educational outreach among local people.
基金financially supported by the German Research Foundation(Deutsche Forschungsgemeinschaft)being part of the project“the Functional Frontier among Mediterranean and Eurosiberian Plant Communities”(ECOFUMER,441909701)+2 种基金Enrique G.de la Riva and Salvador Arenas-Castro are supported by María Zambrano fellowships funded by the Spanish Ministry of Universities and European Union-Next Generation PlanIv an Prieto acknowledges funding from the Fundaci on S eneca(project 20654/JLI/18)co-funded by European Union ERDF funds。
文摘Background:The Iberian Peninsula comprises one of the largest boundaries between Mediterranean and Eurosiberian vegetation,known as sub-Mediterranean zone.This ecotone hosts many unique plant species and communities and constitutes the low-latitude(warm)margin of numerous central European species which co-occur with Mediterranean vegetation.Two of the main species found in this region are the Eurosiberian European beech(Fagus sylvatica L.)and the Mediterranean Pyrenean oak(Quercus pyrenaica Willd.).It remains unclear how the different physiological and adaptive strategies of these two species reflect their niche partitioning within a subMediterranean community and to what extent phenotypic variation(intraspecific variability)is driving niche partitioning across Eurosiberian and Mediterranean species.Methods:We quantified functional niche partitioning,based on the n-dimensional hypervolume to nine traits related to resource acquisition strategies(leaf,stem and root)plus relative growth rate as an additional wholeplant trait,and the environmental niche similarity between Pyrenean oak and European beech.Further,we analyzed the degree of phenotypic variation of both target species and its relationship with relative growth rates(RGR)and environmental conditions.Plant recruitment was measured for both target species as a proxy for the average fitness.Results:Species’functional space was highly segregated(13.09%overlap),mainly due to differences in niche breadth(59.7%)rather than niche replacement(25.6%),and beech showed higher trait variability,i.e.,had larger functional space.However,both species shared the environmental space,i.e.,environmental niches were overlapped.Most plant traits were not related to abiotic variables or RGR,neither did RGR to plant traits.Conclusions:Both target species share similar environmental space,however,show notably different functional resource-use strategies,promoting a high complementarity that contributes to maintaining a high functionality in sub-Mediterranean ecosystems.Therefore,we propose that conservation efforts be oriented to preserve both species in these habitats to maximize ecosystem functionality and resilience.
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.
基金supported by the National Natural Science Foundation of China(Nos.32201545,31971541).
文摘Ice storms,as important sources of frequent and injurious disturbances,drive forest dynamics in the Northern Hemisphere.However,stand-level differential vulnerability to ice storms and the associated factors that predispose forest stands remain unclear.This is particularly concerning in the subtropics where the frequency of ice storms is predicted to increase with global warming.Here we assessed how the impact on three forest stands(early and late secondary-growth forests,and old-growth forests)differed after an extreme ice storm during 20–21 March 2022,and identified the abiotic and biotic factors that determine the damage intensity in the Shennongjia World Natural Heritage Site,a biodiversity conservation hotspot in central China.We found a stand-specific‘middomain effect’where the late secondary-growth forest sustained the most severe damage,the early secondarygrowth forest sustained the least,and the old-growth forest suffered an intermediate amount.‘Crown broken’was the most severe damage type across all three forest stands,although the proportion of‘branch broken’was also high in the old-growth forest.Topography played a significant role in determining the vulnerability of the early secondary-growth forest to severe ice storms whereas the forest structure and composition were important factors in explaining the damage rates in the old-growth forest,although they differed among the damage categories.In contrast,topography,forest structure and composition generally explain the intensity of damage in the late secondary-growth forests.Our results highlight that,in subtropical forests,the intensity of damage caused by severe ice storms and related determining factors are stand-level dependent.We also suggest exploring potential management strategies(e.g.,slow-growing hardwood species that can resist storms should be the main species for reforestation in early secondary-growth forests)to mitigate the risk of future severe ice storms,as well as other wind-related climatic extremes.
基金This project falls under Task Agreement 18-JV-11242311-084 with the USDA Forest ServiceNorthern Research Station,within master joint venture agreement 18-JV-11242311-093 under the Great Rivers Cooperative Ecosystems Studies Unit.
文摘We analyzed national forest inventory data collected from circa 2000–2018 across 37 states in the eastern United States to better understand the influence of forest health related canopy disturbances on the regeneration and recruitment dynamics of upland oaks(Quercus).We found low levels of oak recruitment across all disturbance types examined but limited evidence of any direct effects from the type of disturbance on the population of regenerating oaks.The general lack of differences in oak regeneration response between forest health disturbances and disturbances caused by harvested or non-disturbed plots does not indicate that the effects of forest health disturbances were benign,however.Instead,low level of oak recruitment across all disturbance types highlights the pervasiveness of the trend of shifting composition in once oak-dominated forests where oak is absent or sparse in the regeneration layer.Our results show that oak recruitment was higher when oak was present as advance reproduction prior to disturbance from any cause examined.Collectively,these results lead us to conclude that the widespread inadequacy of oak advance reproduction in mature oak-dominated forests is the prevailing threat to oak forest health and sustainability.We suggest the status of advance reproduction be treated as a co-morbidity when weighing the risk and potential outcomes from other threats to upland oak forests in the eastern United States.
基金E.D. held a SB-doctoral fellowship of the Research Foundation Flanders (FWO, 1S43617N) at the time of data collection
文摘The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor underpinning the low vitality of West-European forests.Selecting tree species with soil ameliorative traits is proposed as an avenue to counteract soil acidification and improve overall forest vitality.Here we evaluate the impact of black cherry(Prunus serotina Ehrh.),a known rich litter species,on the vitality of neighboring pedunculate oak(Quercus robur L.)in ten mixed forests on sand in Germany,Belgium and the Netherlands.We found that black cherry admixture increases foliar N and P to a surplus whereas it causes deficiencies in foliar Mg,thereby resulting in an overall negative effect on oak foliar nutrient concentrations.Contrary,defoliation of oak leaves by herbivory decreases with the proximity of black cherry.Using structural equation modelling(SEM),we tested the hypothesized‘improved soil health’pathway.Our analyses showed that black cherry admixture leads to lower accumulation in the humus layer,resulting in higher soil base saturation which has a positive effect on foliar Ca yet a negative effect on total chlorophyll.Moreover,the SEM illustrated that herbivory of oak leaves decreases when black cherry is admixed,both via dilution and improved soil health.Indirect effects of black cherry on oak vitality via“improved soil health”in our SEM are however small in comparison to direct relations.Hence,our study showed that the combined positive and negative impacts of black cherry on oak vitality are limited,which tempers the potential benefits of using the rich litter species to counteract oak decline via improved soil health–yet,the concern of black cherry as an invasive alien species negatively affecting the vitality of mature pedunculate oak trees may also be exaggerated.
文摘There are two well-known types of tree pruning, crown raising and crown reduction. In Japan, the former has been rarely used, whereas the latter has been widely used. However, it remains unclear which type is more effective to maintain tree vigor and health. Bamboo-leaf oak (Quercus myrsinifolia) trees were experimentally planted and pruned with the two pruning types compared with the no-pruning type. In the crown raising, the lower part of each tree was pruned, and its dominant leader was maintained from the aspect of structural pruning, whereas in the crown reduction, the upper part of each tree was pruned, and the tree height was reduced. The oak trees were observed and recorded in terms of leaf area, leaf weight, branch weight, and tree shape for about one year. The morphological data were statistically analyzed in terms of their allometric relationships. The crown raising type shared the same allometric patterns with the no-pruning types, but the crown reduction type did not. The trees of the crown reduction type were more likely to suffer from pests and disease. The allometric differences between the two pruning types may be considered the result of a decline in whole-tree vigor and health in crown reduction. The crown raising seemed more likely to control tree vigor and health than the crown reduction. The present results would help arborists determine which method to use for pruning.
文摘Cork oak in Maamora forest is experiencing the dieback phenomenon. The evaluation of the latter in this forest has gained the importance over time and with the solicitation of managers to objectify its phytosanitary situation. Aiming at prioritizing management actions, remote sensing seems to be an effective tool to inquire about stands’ health conditions and their evolution. To this end, this study aims at mapping and validating health status of cork oak stands in Maamora. Sentinel 2 images in 2015 and 2020 were processed to calculate the differential normalized difference water index (NDWI), revealing vegetation moisture variation caused by drought. A statistical method based on thresholds was used to map cork oak dieback stands, those with no changes and those recovered. Results have shown that 54.63% of cork oak in Maamora forest have not changed in terms of phytosanitary situation between 2015 and 2020, 31.10% of oak stands are afflicted by a slight decline and 12.97% by a severe decline. Areas with slight or strong recovery remain minimal and represent 1.04% and 0.25% respectively. Ground data indicated that the map generated displayed a good distinction between stands severely and slightly declined with a global accuracy of 66.66%. Therefore, further research elaborating an advanced vegetation index reflecting the various factors of dieback would be of much importance.
文摘Afforestation has been observed as a green trend in urban areas. The incorporation of trees in urban infrastructure is highly recommended to act as a solution to outlined environmental problems such as global warming. However, it has been precipitously introduced in cities, towns, and metropolitans. The introduction of the green practice was so abrupt that it became devoid to meeting the essential needs for tree growth, thus, failing to bring out the desired effects. Inappropriately selecting and planting trees in urban spaces has resulted in stressed trees that are deficient at reaching up to the calculated goals and in the long run end up being problematic. The main objective of this study is to evaluate the implications of planting southern live oak (Quercus virginiana) trees in the wrong urban space so as to aid in recommending sustainable green solutions for the urban community. By studying southern live oaks planted in Howell Community Park and three randomly selected areas in Southern University Baton Rouge Campus, this study analyzes how the selection of these tree species in the urban spaces influenced their growth and general well-being. These urban spaces were randomly drafted based on accessibility and availability of several southern live oaks. Planting approaches in the four study areas were explored and the general health condition of the trees was determined using the tree appraisal method presented by the i-tree model: my tree. ArcGIS collector was used to collect the GPS coordinates of the trees and ArcMap was used to generate the maps of the study areas. ArcMap software geolocated the coordinates of the southern live oaks in all the four-study areas. The software was used to generate shapefiles of the four study areas and their location in East Baton Rouge. The analysis of the results proved that none of the southern live oaks had an excellent health condition and most of the trees experienced different issues due to planting them in the wrong urban spaces.
文摘采用激光粒度分析法测定超细 OAK 木炭及竹炭粉粒度,探讨了分散剂种类、分散时间、搅拌速度、超声时间等因素对超细 OAK 木炭及竹炭粉粒度的影响。结果表明:以六偏磷酸钠为分散剂时分散效果最佳,其用量为0.06g/(100mlOAK 木炭及竹炭粉乳液);在测定时选择循环搅拌泵速为2200~2400r/min 较好;超声时间为200s 左右时,可达到最佳分散效果。
文摘Pre- and post-defoliation radial growth rates were used to examine the effects of silvicultural thinning and two consecutive years of gypsy moth (Lymantria dispar L.) defoliation on Quercus spp. wood volume production. In the first phase of the study, tree rings from 65 dissected stems, were used to develop polynomial models to estimate annual cumulative volume (m3) increment for the entire merchantable stem, as a function of dbh (tree diameter at 1.37 m above the ground). In Phase II of the study, 81 additional trees were sampled using only increment cores. Cumulative diameter increments from the cores were used in the polynomial models to compare tree volume growth changes during and after defoliation among the thinning treatments. Even though there was no significant difference in estimated volume lost during defoliation among treatments, post-defoliation growth was enhanced by thinning. Total volume reduction from defoliation ranged from 28,049 (±17,462) cm3 to 25,993 (±16,251) cm3 per tree. The stand receiving the thinning treatment with the lowest residual stocking produced significantly more volume (P = 0.002) after defoliation than the other treatments.