| ice storm damage and early recovery in an old-growth forest. | we quantified the damage caused by a major ice storm to individual trees in two 1-ha permanent plots located at mont st. hilaire in southwestern québec, canada. the storm, which occurred in january 1998, is the worst on record in eastern north america; glaze ice on the order of 80-100 mm accumulated at our study site. all but 3% of the trees (dbh > or = 10 cm) lost at least some crown branches, and 35% lost more than half their crown. damage to trees increased in the order: tsuga canadensis, bet ... | 2001 | 11339708 |
| hypersensitivity to common tree pollens in new york city patients. | testing for tree pollen hypersensitivity typically requires the use of several tree pollens. identifying patterns of cross-sensitivity to tree pollens could reduce the number of trees used for testing. the goal of this study was to relate reported tree pollen levels to hypersensitivity patterns. three hundred seventy-one allergy patients were tested serologically for hypersensitivity toward prevalent tree pollens in the surrounding new york area over the years 1993-2000. specific tree pollens th ... | 2002 | 12221895 |
| does canopy position affect wood specific gravity in temperate forest trees? | the radial increases in wood specific gravity known in many tree species have been interpreted as providing mechanical support in response to the stresses associated with wind loading. this interpretation leads to the hypothesis that individuals reaching the canopy should (1) be more likely to have radial increases in specific gravity and (2) exhibit greater increases than individuals in the subcanopy. wood specific gravity was determined for three species of forest trees (acer rubrum, fagus gra ... | 2003 | 12646497 |
| survival and development of lymantria monacha (lepidoptera: lymantriidae) on north american and introduced eurasian tree species. | lymantria monacha (l.) (lepidoptera: lymantriidae), the nun moth, is a eurasian pest of conifers that has potential for accidental introduction into north america. to project the potential host range of this insect if introduced into north america, survival and development of l. monacha on 26 north american and eight introduced eurasian tree species were examined. seven conifer species (abies concolor, picea abies, p. glauca, p. pungens, pinus sylvestris with male cones, p. menziesii variety gla ... | 2003 | 12650343 |
| sensitivity of red oak (quercus rubra l.) and american beech (fagus grandifolia ehrh.) seedlings to sodium salts in solution culture. | sodium salt sensitivity of red oak (quercus rubra l.) and american beech (fagus grandifolia ehrh.) was evaluated in solution culture. both species showed symptoms of salt injury when grown in the presence of less than 10 mm na. in red oak, leaf symptoms first appeared at a sodium concentration of 6.0 mm and leaf weight was significantly reduced at 7.5 mm na. leaf, stem and root dry weights of american beech were significantly reduced in the presence of 4.0 mm sodium. in both species, browning of ... | 1988 | 14972826 |
| effects of aqueous extracts from leaves and leaf litter on the abundance and diversity of soil gymnamoebae in laboratory microcosm cultures. | the distribution and abundance of microbiota in soil and litter may be significantly affected by the quality and quantity of localized patches of leaf organic matter. this study examined the relative effects of aqueous extracts of shed autumn leaves from american beech (fagus grandifolia), sugar maple (acer saccharum), red oak (quercus rubra), and white oak (quercus alba) on the density and diversity of gymnamoebae in laboratory cultures. overall, the beech leaf extract produced the most growth ... | 2005 | 16014018 |
| a requirement for sucrose in xylem sap flow from dormant maple trees. | the response of excised stem segments of several tree species to freezing and thawing cycles was studied. all species studied (thuja occidentalis, fagus grandifolia, and betula papyrifera) except maple (acer spp.) exuded sap while freezing and absorbed on thawing. maple stems absorbed sap while freezing and exuded sap during the thaw only when sucrose was present in the vessel solution. increased concentration of sucrose in the vessel sap led to increased exudation. in the absence of sucrose, ma ... | 1987 | 16665468 |
| photosynthetic responses to understory shade and elevated carbon dioxide concentration in four northern hardwood tree species. | seedling responses to elevated atmospheric co(2) concentration ([co(2)]) and solar irradiance were measured over two growing seasons in shade-tolerant acer saccharum marsh. and fagus grandifolia j.f. ehrh. and shade-intolerant prunus serotina, a j.f. ehrh. and betula papyrifera marsh. seedlings were exposed to a factorial combination of [co2] (ambient and elevated (658 micromol mol-1)) and understory shade (deep and moderate) in open-top chambers placed in a forest understory. the elevated [co(2 ... | 2006 | 17169898 |
| forest vegetation monitoring and foliar chemistry of red spruce and red maple at acadia national park in maine. | the usda forest service forest health monitoring (fhm) program indicators, including forest mensuration, crown condition classification, and damage and mortality indicators were used in the cadillac brook and hadlock brook watershed forests at acadia national park (anp) along coastal maine. cadillac brook watershed burned in a wildfire in 1947. hadlock brook watershed, undisturbed for several centuries, serves as the reference site. these two small watersheds have been gauged and monitored at an ... | 2007 | 17180435 |
| plant and soil natural abundance delta (15)n: indicators of relative rates of nitrogen cycling in temperate forest ecosystems. | watersheds within the catskill mountains, new york, receive among the highest rates of nitrogen (n) deposition in the northeastern united states and are beginning to show signs of n saturation. despite similar amounts of n deposition across watersheds within the catskill mountains, rates of soil n cycling and n retention vary significantly among stands of different tree species. we examined the potential use of delta (15)n of plants and soils as an indicator of relative forest soil n cycling rat ... | 2007 | 17479293 |
| agricultural legacies in forest environments: tree communities, soil properties, and light availability. | temperate deciduous forests across much of europe and eastern north america reflect legacies of past land use, particularly in the diversity and composition of plant communities. intense disturbances, such as clearing forests for agriculture, may cause persistent environmental changes that continue to shape vegetation patterns as landscapes recover. we assessed the long-term consequences of agriculture for environmental conditions in central new york forests, including tree community structure a ... | 2007 | 17489252 |
| natural and manipulated populations of the treehole mosquito, ochlerotatus triseriatus, at its northernmost range limit in southern ontario, canada. | ochlerotatus triseriatus, the eastern treehole mosquito, reaches its northernmost range limit in the extreme southeast of canada. as a known vector of west nile and la crosse encephalitis viruses and a potential vector of eastern equine encephalitis, its population biology is of interest. in southern ontario, high larval densities occur in urban woodlots within sugar maple and american beech treehole communities comprising rotifers, nematode worms, mites, other dipterans, and scirtid beetles. tr ... | 2007 | 18260525 |
| sim4cc: a cross-species spliced alignment program. | advances in sequencing technologies have accelerated the sequencing of new genomes, far outpacing the generation of gene and protein resources needed to annotate them. direct comparison and alignment of existing cdna sequences from a related species is an effective and readily available means to determine genes in the new genomes. current spliced alignment programs are inadequate for comparing sequences between different species, owing to their low sensitivity and splice junction accuracy. a new ... | 2009 | 19429899 |
| two lactarius species associated with a relict fagus grandifolia var. mexicana population in a mexican montane cloud forest. | ectomycorrhizal (em) fleshy fungi are being monitored in a population of fagus grandifolia var. mexicana persisting in a montane cloud forest refuge on a volcano in a subtropical region of central veracruz (eastern mexico). the population of fagus studied represents one of the 10 recognized forest fragments still housing this tree genus in mexico. this is the first attempt to document em fungi associated with this tree species in mexico. we present evidence of the ectomycorrhizal symbiosis for l ... | 2010 | 20120238 |
| permanent genetic resources added to molecular ecology resources database 1 may 2009-31 july 2009. | this article documents the addition of 512 microsatellite marker loci and nine pairs of single nucleotide polymorphism (snp) sequencing primers to the molecular ecology resources database. loci were developed for the following species: alcippe morrisonia morrisonia, bashania fangiana, bashania fargesii, chaetodon vagabundus, colletes floralis, coluber constrictor flaviventris, coptotermes gestroi, crotophaga major, cyprinella lutrensis, danaus plexippus, fagus grandifolia, falco tinnunculus, fle ... | 2009 | 21564933 |
| utilizing pigment-producing fungi to add commercial value to american beech (fagus grandifolia). | american beech (fagus grandifolia) is an abundant, underutilized tree in certain areas of north america, and methods to increase its market value are of considerable interest. this research utilized pigment-producing fungi to induce color in american beech to potentially establish its use as a decorative wood. wood samples were inoculated with trametes versicolor, xylaria polymorpha, inonotus hispidus, and arthrographis cuboidea to induce fungal pigmentation. black pigmentation (t. versicolor, x ... | 2011 | 21931972 |
| incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape. | there are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. in this paper, we present a framework for revising the potential distribution of tree species native to the western ecoregion of nova scotia, canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (psd). the ps ... | 2017 | 28207782 |
| tree demography suggests multiple directions and drivers for species range shifts in mountains of northeastern united states. | climate change is expected to lead to upslope shifts in tree species distributions, but the evidence is mixed partly due to land-use effects and individualistic species responses to climate. we examined how individual tree species demography varies along elevational climatic gradients across four states in the northeastern united states to determine whether species elevational distributions and their potential upslope (or downslope) shifts were controlled by climate, land-use legacies (past logg ... | 2016 | 27935175 |
| biochar mitigates negative effects of salt additions on two herbaceous plant species. | addition of pyrolyzed biomass ("biochar") to soils has commonly been shown to increase crop yields and alleviate plant stresses associated with drought and exposure to toxic materials. here we investigate the ability of biochar (at two dosages: 5 and 50 t ha(-1)) to mitigate salt-induced stress, simulating road salt additions in a factorial glasshouse experiment involving the broadleaved herbaceous plants abutilon theophrasti and prunella vulgaris. salt additions of 30 g m(-2) nacl to unamended ... | 2013 | 23796889 |
| insect herbivores increase mortality and reduce tree seedling growth of some species in temperate forest canopy gaps. | insect herbivores help maintain forest diversity through selective predation on seedlings of vulnerable tree species. although the role of natural enemies has been well-studied in tropical systems, relatively few studies have experimentally manipulated insect abundance in temperate forests and tracked impacts over multiple years. we conducted a three-year experiment (2012-2014) deterring insect herbivores from seedlings in new treefall gaps in deciduous hardwood forests in maryland. during this ... | 2017 | 28344904 |
| effects of structural complexity on within-canopy light environments and leaf traits in a northern mixed deciduous forest. | canopy structure influences forest productivity through its effects on the distribution of radiation and the light-induced changes in leaf physiological traits. due to the difficulty of accessing and measuring forest canopies, few field-based studies have quantitatively linked these divergent scales of canopy functioning. the objective of our study was to investigate how canopy structure affects light profiles within a forest canopy and whether leaves of mature trees adjust morphologically and b ... | 2017 | 28100711 |
| evaluating the ecological impacts of salvage logging: can natural and anthropogenic disturbances promote coexistence? | salvage logging following windthrow is common throughout forests worldwide even though the practice is often considered inimical to forest recovery. because salvaging removes trees, crushes seedlings, and compacts soils, many warn this practice may delay succession, suppress diversity, and alter composition. here, over 8 yr following windthrow, we experimentally evaluate how salvaging affects tree succession across 11 gaps in eastern deciduous forests of pennsylvania, wherein each gap was divide ... | 2016 | 27459786 |
| modeled effects of soil acidification on long-term ecological and economic outcomes for managed forests in the adirondack region (usa). | sugar maple (acer saccharum) is among the most ecologically and economically important tree species in north america, and its growth and regeneration is often the focus of silvicultural practices in northern hardwood forests. a key stressor for sugar maple (sm) is acid rain, which depletes base cations from poorly-buffered forest soils and has been associated with much lower sm vigor, growth, and recruitment. however, the potential interactions between forest management and soil acidification - ... | 2016 | 27179322 |
| community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest. | exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (c) dynamics are poorly understood. we used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (lumbricus terrestris [anecic], aporrectodea trapezoides [endogeic], and eisenia fetida [epigeic]) on c distributions and storage in reconstructed soil profiles from a sandy temperate forest soil by measu ... | 2013 | 24597228 |
| indirect effects of pandemic deer overabundance inferred from caterpillar-host relations. | externally feeding phytophagous insect larvae (i.e., caterpillars, here, larval lepidoptera and sawflies, hymenoptera: symphyta) are important canopy herbivores and prey resources in temperate deciduous forests. however, composition of forest trees has changed dramatically in the eastern united states since 1900. in particular, browsing by high densities of white-tailed deer (odocoileus virginianus) has resulted in forests dominated by browse-tolerant species, such as black cherry (prunus seroti ... | 2013 | 23678968 |
| foliar δ15n is affected by foliar nitrogen uptake, soil nitrogen, and mycorrhizae along a nitrogen deposition gradient. | foliar nitrogen isotope (δ(15)n) composition patterns have been linked to soil n, mycorrhizal fractionation, and within-plant fractionations. however, few studies have examined the potential importance of the direct foliar uptake of gaseous reactive n on foliar δ(15)n. using an experimental set-up in which the rate of mycorrhizal infection was reduced using a fungicide, we examined the influence of mycorrhizae on foliar δ(15)n in potted red maple (acer rubrum) seedlings along a regional n deposi ... | 2013 | 23070141 |
| landscape ecosystem classification in the cherokee national forest, east tennessee, u.s.a. | a landscape ecosystem classification is described for the 43 800 ha foothills section (elevation 305 to 610 m) of the southern unit of the cherokee national forest. vegetative cover, landform, and soils data were obtained from sixty 0.04 ha plots located in stands representing late successional stages. vegetation data were grouped by dominant cover type utilizing agglomerative, hierarchical clustering and detrended correspondence analysis. detrended canonical correspondence analysis (dcca) and s ... | 1996 | 24198013 |
| osmotic potential of several hardwood species as affected by manipulation of throughfall precipitation in an upland oak forest during a dry year. | components of dehydration tolerance, including osmotic potential at full turgor (psi(pio)) and osmotic adjustment (lowering of psi(pio)), of several deciduous species were investigated in a mature, upland oak forest in eastern tennessee. beginning july 1993, the trees were subjected to one of three throughfall precipitation treatments: ambient, ambient minus 33% (dry treatment), and ambient plus 33% (wet treatment). during the dry 1995 growing season, leaf water potentials of all species decline ... | 1998 | 12651368 |
| acorn dispersal by the blue jay (cyanocitta cristata). | blue jays transported and cached 133,000 acorns from a stand of quercus palustris trees in blacksburg, virginia, representing 54% of the total mast crop. a further 20% (49,000) of the mast crop was eaten by jays at the collecting site. a large proportion of the nuts remaining beneath the collecting trees was parasitized by curculionid larvae. the number of nuts transported per caching trip ranged from 1-5 with a mean of 2.2. mean distance between seed trees and caches was 1.1 km (range: 100 m-1. ... | 1981 | 28311093 |
| unexpected presence of fagus orientalis complex in italy as inferred from 45,000-year-old dna pollen samples from venice lagoon. | phylogeographic analyses on the western euroasiatic fagus taxa (f. orientalis, f. sylvatica, f. taurica and f. moesiaca) is available, however, the subdivision of fagus spp. is unresolved and there is no consensus on the phylogeny and on the identification (both with morphological than molecular markers) of fagus eurasiatic taxa. for the first time molecular analyses of ancient pollen, dated at least 45,000 years ago, were used in combination with the phylogeny analysis on current species, to id ... | 2007 | 17767734 |
| silica uptake and release in live and decaying biomass in a northern hardwood forest. | in terrestrial ecosystems, a large portion (20-80%) of the dissolved si (dsi) in soil solution has passed through vegetation. while the importance of this "terrestrial si filter" is generally accepted, few data exist on the pools and fluxes of si in forest vegetation and the rate of release of si from decomposing plant tissues. we quantified the pools and fluxes of si through vegetation and coarse woody debris (cwd) in a northern hardwood forest ecosystem (watershed 6, w6) at the hubbard brook e ... | 2016 | 27870019 |
| two new lactarius species from a subtropical cloud forest in eastern mexico. | two species of lactarius from the subtropical montane cloud forest of central veracruz are described as new. both species are placed in subgenus lactarius based on an accurate study of macro- and micromorphological features and supported by molecular phylogenetic analyses of a single nuc rdna its1-5.8s-its2 (its), a concatenated its, d1, and d2 domains of nuc 28s rdna (28s), and part of the second largest subunit of the rna polymerase ii (rpb2) (6-7 region) sequence datasets. in the phylogenetic ... | 2016 | 27549618 |
| calcium and aluminum cycling in a temperate broadleaved deciduous forest of the eastern usa: relative impacts of tree species, canopy state, and flux type. | ca/al molar ratios are commonly used to assess the extent of aluminum stress in forests. this is among the first studies to quantify ca/al molar ratios for stemflow. ca/al molar ratios in bulk precipitation, throughfall, stemflow, litter leachate, near-trunk soil solution, and soil water were quantified for a deciduous forest in northeastern md, usa. data were collected over a 3-year period. the ca/al molar ratios in this study were above the threshold for aluminum stress (<1). fagus grandifolia ... | 2015 | 26100445 |
| habitat differences influence genetic impacts of human land use on the american beech (fagus grandifolia). | natural reforestation after regional forest clearance is a globally common land-use sequence. the genetic recovery of tree populations in these recolonized forests may depend on the biogeographic setting of the landscape, for instance whether they are in the core or in the marginal part of the species' range. using data from 501 individuals genotyped across 7 microsatellites, we investigated whether regional differences in habitat quality affected the recovery of genetic variation in a wind-poll ... | 2014 | 25138571 |
| cascading effects of a highly specialized beech-aphid-fungus interaction on forest regeneration. | specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. in contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. however, we describe a cascade of indirect interactions whereby a specialist sooty mold (scorias spongiosa) colonizes the honeydew from a specialist beech aphid (grylloprociphilus imbricator), ultimately decreasing the surv ... | 2014 | 25024911 |
| a technique to screen american beech for resistance to the beech scale insect (cryptococcus fagisuga lind.). | beech bark disease (bbd) results in high levels of initial mortality, leaving behind survivor trees that are greatly weakened and deformed. the disease is initiated by feeding activities of the invasive beech scale insect, cryptococcus fagisuga, which creates entry points for infection by one of the neonectria species of fungus. without scale infestation, there is little opportunity for fungal infection. using scale eggs to artificially infest healthy trees in heavily bbd impacted stands demonst ... | 2014 | 24894494 |
| meteorological influences on stemflow generation across diameter size classes of two morphologically distinct deciduous species. | many tree species have been shown to funnel substantial rainfall to their stem base as stemflow flux, given a favorable stand structure and storm conditions. as stemflow is a spatially concentrated flux, prior studies have shown its impact on ecohydrological and biogeochemical processes can be significant. less work has been performed examining stemflow variability from meteorological conditions compared to canopy structural traits. as such, this study performs multiple regressions: (1) to exami ... | 2014 | 24615637 |
| mature beech trees (fagus grandifolia; fagaceae) are persistently clonal in coves and beech gaps in the great smoky mountains. | angiosperms frequently have mixed sexual and asexual reproductive strategies, which can have significant consequences for population and community structure. many tree species respond to disturbance by vegetative sprouting over sexual reproduction, but the ability to do so varies within and among species and is poorly studied. we tested the hypothesis that root sprouting in fagus grandifolia is more important in high-elevation beech forests (extreme environmental conditions), relative to lower-e ... | 2014 | 24491343 |
| facilitative effects of group feeding on performance of the saddleback caterpillar (lepidoptera: limacodidae). | gregarious feeding by insect herbivores is a widely observed, yet poorly understood, behavioral adaptation. previous research has tested the importance of group feeding for predator deterrence, noting the ubiquity of aposematism among group-feeding insects, but few studies have examined the role of feeding facilitation for aggregates of insect herbivores. we tested the hypothesis that group feeding has facilitative effects on performance of the saddleback caterpillar, acharia stimulea clemens, a ... | 2014 | 24472205 |
| subfossil leaves reveal a new upland hardwood component of the pre-european piedmont landscape,lancaster county, pennsylvania. | widespread deforestation, agriculture, and construction of milldams by european settlers greatly influenced valley-bottom stream morphology and riparian vegetation in the northeastern usa. the former broad, tussock-sedge wetlands with small, anastomosing channels were converted into today's incised, meandering streams with unstable banks that support mostly weedy, invasive vegetation. vast accumulations of fine-grained "legacy" sediments that blanket the regional valley-bottom piedmont landscape ... | 2013 | 24236120 |
| physical and chemical properties of some imported woods and their degradation by termites. | the influence of physical and chemical properties of 20 species of imported wood on degradation of the wood by termites under field conditions was studied. the wood species studied were: sycamore maple, acer pseudoplatanus l. (sapindales: sapindaceae) (from two countries), camphor, dryobalanops aromatic c.f.gaertner (malvales: dipterocarpaceae), beech, fagus grandifolia ehrhart (fagales: fagaceae), f. sylvatica l. (from two countries), oak, quercus robur l., ash, fraxinus angustifolia vahl (lami ... | 2013 | 23906349 |
| evaluation of digital photography for quantifying cryptococcus fagisuga (hemiptera: eriococcidae) density on american beech trees. | beech scale (cryptococcus fagisuga lindinger) (hemiptera: eriococcidae) is an invasive forest insect established in the eastern united states and canada. it predisposes american beech (fagus grandifolia ehrhart) trees to infection by neonectria spp. fungi causing beech bark disease. white wax secreted by the diminutive scales obscures individual insects, making it difficult to accurately quantify beech scale density. our goals were to 1) evaluate the relationship between the area of wax and numb ... | 2013 | 23865198 |
| thirty-two years of change in an old-growth ohio beech-maple forest. | old-growth forests dominated by understory-tolerant tree species are among forest types most likely to be in equilibrium. however, documentation of the degree to which they are in equilibrium over decades-long time periods is lacking. changes in climate, pathogens, and land use all are likely to impact stand characteristics and species composition, even in these forests. here, 32 years of vegetation changes in an old-growth beech (fagus grandifolia)-sugar maple (acer saccharum) forest in hueston ... | 2013 | 23858656 |
| phenological variation in the composition of a temperate forest leaf tie community. | arthropod communities in an array of temperate ecosystems follow similar phenological patterns of distinct compositional turnovers during the course of a season. the arthropod community inhabiting leaf ties is no exception. many caterpillars build leaf ties, shelters between overlapping leaves attached together with silk, which are colonized secondarily by a variety of arthropods. we created experimental leaf ties by clipping overlapping leaves together with metal clips. we censused the arthropo ... | 2013 | 23339783 |
| comparisons of protein profiles of beech bark disease resistant and susceptible american beech (fagus grandifolia). | | 2013 | 23317283 |
| the influence of moisture content variation on fungal pigment formation in spalted wood. | eight fungal species known to produce wood pigmentation were tested for reaction to various moisture contents in two hardwood species. fungal pigmentation by trametes versicolor and xylaria polymorpha was stimulated at low water concentrations in both acer saccharum (sugar maple) and fagus grandifolia (american beech), while inonotus hispidus and polyporus squamosus were stimulated above 22-28% and 34-38% moisture content in beech and in sugar maple respectively. fomes fomentarius and polyporus ... | 2012 | 23245292 |
| multi-decadal drought and amplified moisture variability drove rapid forest community change in a humid region. | climate variability, particularly the frequency of extreme events, is likely to increase in the coming decades, with poorly understood consequences for terrestrial ecosystems. hydroclimatic variations of the medieval climate anomaly (mca) provide a setting for studying ecological responses to recent climate variability at magnitudes and timescales comparable to expectations of coming centuries. we examined forest response to the mca in the humid western great lakes region of north america, using ... | 2012 | 22624302 |
| improving sap flux density measurements by correctly determining thermal diffusivity, differentiating between bound and unbound water. | several heat-based sap flow methods, such as the heat field deformation method and the heat ratio method, include the thermal diffusivity d of the sapwood as a crucial parameter. despite its importance, little attention has been paid to determine d in a plant physiological context. therefore, d is mostly set as a constant, calculated during zero flow conditions or from a method of mixtures, taking into account wood density and moisture content. in this latter method, however, the meaning of the ... | 2012 | 22543477 |
| morphological and molecular identification of the ectomycorrhizal association of lactarius fumosibrunneus and fagus grandifolia var. mexicana trees in eastern mexico. | a population of fagus grandifolia var. mexicana (covering ca. 4.7 ha) is established in a montane cloud forest refuge at acatlan volcano in eastern mexico (veracruz state), and it represents one of only ten populations of this species known to occur in the country (each stand covers ca. 2-35 ha in extension) and one of the southernmost in the continent. sporocarps of several ectomycorrhizal macrofungi have been observed in the area, and among them, individuals of the genus lactarius are common i ... | 2012 | 22402818 |
| anticipation and tracking of pulsed resources drive population dynamics in eastern chipmunks. | pulsed systems are characterized by boom and bust cycles of resource production that are expected to cascade through multiple trophic levels. many of the consumers within pulsed resource systems have specific adaptations to cope with these cycles that may serve to either amplify or dampen their community-wide consequences. we monitored a seed predator, the eastern chipmunk (tamias striatus), in an american beech (fagus grandifolia) dominated forest, and used capture-mark-recapture analyses to es ... | 2011 | 22164826 |
| a new species of lactarius (subgenus gerardii) from two relict fagus grandifolia var. mexicana populations in mexican montane cloud forests. | a new milkcap species, lactarius fuscomarginatus, was found in the subtropical region of central veracruz (eastern mexico) associated with two relict populations of fagus grandifolia var. mexicana. the species is characterized macroscopically by its dark pileus and stipe and by its distant and whitish lamellae with blackish to blackish brown edges. a molecular phylogenetic analyses based on its and lsu nucdna sequences confirms the delimitation of this new taxon and places l. fuscomarginatus in ... | 2012 | 21914830 |
| bolete diversity in two relict forests of the mexican beech (fagus grandifolia var. mexicana; fagaceae). | the current distribution of the endangered mexican beech [fagus grandifolia var. mexicana (martinez) little] is restricted to relict isolated populations in small remnants of montane cloud forest in northeastern mexico, and little is known about its associated biota. we sampled bolete diversity in two of these monospecific forests in the state of hidalgo, mexico. we compared alpha diversity, including species richness and ensemble structure, and analyzed beta diversity (dissimilarity in species ... | 2010 | 21622453 |
| host density drives the postglacial migration of the tree parasite, epifagus virginiana. | to survive changes in climate, successful species shift their geographic ranges to remain in suitable habitats. for parasites and other highly specialized species, distributional changes not only are dictated by climate but can also be engineered by their hosts. the extent of host control on parasite range expansion is revealed through comparisons of host and parasite migration and demographic histories. however, understanding the codistributional history of entire forest communities is complica ... | 2010 | 20841421 |
| optimal partitioning theory revisited: nonstructural carbohydrates dominate root mass responses to nitrogen. | under optimal partitioning theory (opt), plants preferentially allocate biomass to acquire the resource that most limits growth. within this framework, higher root mass under low nutrients is often assumed to reflect an allocation response to build more absorptive surface. however, higher root mass also could result from increased storage of total nonstructural carbohydrates (tnc) without an increase in non-storage mass or root surface area. to test the relative contributions of tnc and non-stor ... | 2010 | 20380206 |
| codominance of acer saccharum and fagus grandifolia: the role of fagus root sprouts along a slope gradient in an old-growth forest. | we studied how the unusual capacity of mature fagus grandifolia to form clumps of clonal stems from root sprouts can contribute to its frequent codominance with acer saccharum in southern quebec, canada. in an old-growth forest, the degree of dominance by the two species shifted along topographic gradients spanning a few hundreds of meters, with fagus more frequent on lower slopes and acer on upper slopes. the frequency distribution of fagus stem diameter had an inverse j distribution at all slo ... | 2010 | 20182904 |
| large-scale synchrony of gap dynamics and the distribution of understory tree species in maple-beech forests. | large-scale synchronous variations in community dynamics are well documented for a vast array of organisms, but are considerably less understood for forest trees. because of temporal variations in canopy gap dynamics, forest communities-even old-growth ones-are never at equilibrium at the stand scale. this paucity of equilibrium may also be true at the regional scale. our objectives were to determine (1) if nonequilibrium dynamics caused by temporal variations in the formation of canopy gaps are ... | 2010 | 19669164 |
| leaf litter species evenness influences nonadditive breakdown in a headwater stream. | species loss directly affects the magnitude and stability of various ecosystem processes, and species composition can drive this phenomenon. much of the evidence that species loss affects ecosystem processes comes from experiments where species richness was manipulated while holding abundance/biomass of individual species constant. given that species rarely coexist in equal proportions, neglecting evenness might under/overestimate the role of important species combinations. we examined leaf litt ... | 2009 | 19569379 |
| partitioning the factors of spatial variation in regeneration density of shade-tolerant tree species. | understanding coexistence of highly shade-tolerant tree species is a longstanding challenge for forest ecologists. a conceptual model for the coexistence of sugar maple (acer saccharum) and american beech (fagus grandibfolia) has been proposed, based on a low-light survival/high-light growth trade-off, which interacts with soil fertility and small-scale spatiotemporal variation in the environment. in this study, we first tested whether the spatial distribution of seedlings and saplings can be pr ... | 2008 | 18959325 |
| influences of a calcium gradient on soil inorganic nitrogen in the adirondack mountains, new york. | studies of the long-term impacts of acidic deposition in europe and north america have prompted growing interest in understanding the dynamics linking the nitrogen (n) and calcium (ca) cycles in forested watersheds. while it has been shown that increasing concentrations of nitrate (no3-) through atmospheric deposition or through nitrification can increase ca loss, the reciprocal effects of ca on n transformation processes have received less attention. we studied the influence of soil ca availabi ... | 2008 | 18839757 |
| do interspecific differences in sapling growth traits contribute to the co-dominance of acer saccharum and fagus grandifolia? | acer saccharum and fagus grandifolia are among the most dominant late-successional tree species in north america. the influence of sapling growth responses to canopy gaps on the co-dominance of the two species in an old-growth forest in southern quebec, canada was examined. two predictions were evaluated: (a) f. grandifolia is more shade tolerant than a. saccharum due to greater sapling leaf area and net production per sapling in closed-canopy conditions; and (b) the height growth rate of a. sac ... | 2008 | 17942590 |
| patterns of molecular and morphological differentiation in fagus (fagaceae): phylogenetic implications. | to study phylogenetic relationships among species of fagus, the internal transcribed spacer regions its1 and its2 of the nuclear ribosomal dna and morphological data were analyzed. both molecular and morphologically based phylogenies suggest that eurasian species of fagus subgenus fagus are basal to the north american fagus grandifolia. the subgenus fagus is a paraphyletic group basal to three east asian species forming the subgenus engleriana. due to a considerably large amount of dna polymorph ... | 2005 | 21652485 |
| on the cover. american beech. | | 2004 | 15191014 |
| leaf phenology, photosynthesis, and the persistence of saplings and shrubs in a mature northern hardwood forest. | we quantified leaf phenologies of saplings and overstory trees of sugar maple (acer saccharum marsh.) and american beech (fagus grandifolia ehrh.), and the shrub hobblebush viburnum (viburnum alnifolium marsh.) in a 72-year-old northern hardwood forest. seasonal changes in irradiance in the shrub layer, and in the leaf co(2) exchange of viburnum, and sugar maple and beech saplings were also measured. leaf expansion occurred earlier in the spring and green leaves were retained later in the autumn ... | 1998 | 12651367 |
| dendrochemical analysis of lead and calcium in southern appalachian american beech. | the health of the northern hardwood forest in the southern appalachian mountains of tennessee, north carolina, and virginia has gained attention from the media and environmental stakeholders due to a purported decline in forest health at higher elevations. this project examined lead (pb) and calcium (ca) concentrations in growth rings of an important northern hardwood species, american beech (fagus grandifolia ehrh.) at mount rogers and whitetop mountain, virginia and attempted to examine concen ... | 2013 | 12175031 |
| relationships among root branch order, carbon, and nitrogen in four temperate species. | the objective of this study was to examine how root length, diameter, specific root length, and root carbon and nitrogen concentrations were related to root branching patterns. the branching root systems of two temperate tree species, acer saccharum marsh. and fraxinus americana l., and two perennial herbs from horizontal rhizomes, hydrophyllum canadense l. and viola pubescens ait., were quantified by dissecting entire root systems collected from the understory of an a. saccharum-fagus grandifol ... | 1997 | 28308123 |
| a community classification system for forest evaluation: development, validation, and extrapolation. | a community classification system integrating vegetation and landforms was developed for the 8,054-ha cheatham wildlife management area (cwma), located on the western highland rim of tennessee, usa, to obtain information on which to base multiresource land management decisions. a subjective procedure (synthesis tables) and several objective techniques (factor analysis, cluster analysis, and canonical discrimination) were used to evaluate importance values of overstory and midstory species, cover ... | 1996 | 24198012 |
| the fate of (15)n-labelled nitrate additions to a northern hardwood forest in eastern maine, usa. | we followed the movements of (15)n-labelled nitrate additions into biomass and soil pools of experimental plots (15×15 m each) in a mid-successional beech-maple-birch-spruce forest in order to identify sinks for nitrate inputs to a forest ecosystem. replicate plots (n=3) were spray-irrigated with either 28 or 56 kg n ha(-1) year(-1) using (15)n-labelled nitric acid solutions (δ(15)n = 344‰ ) during four successive growing seasons (april-october). the (15)n contents of foliage, bolewood, forests ... | 1995 | 28306822 |
| effects of co2 enrichment on whole-plant carbon budget of seedlings of fagus grandifolia and acer saccharum in low irradiance. | carbon exchange rates (cer) and whole-plant carbon balances of beech (fagus grandifolia) and sugar maple (acer saccharum) were compared for seedlings grown under low irradiance to determine the effects of atmospheric co2 enrichment on shade-tolerant seedlings of co-dominant species. under contemporary atmospheric co2, photosynthetic rate per unit mass of beech was lower than for sugar maple, and atmospheric co2 enrich ment enhanced photosynthesis for beech only. aboveground respiration per unit ... | 1994 | 28312793 |
| autumnal leaf conductance and apparent photosynthesis by saplings and sprouts in a recently disturbed northern hardwood forest. | leaf surface conductance and apparent photosynthesis were measured during late summer and autumn on saplings and sprouts of pin cherry (prunus pensylvanica), yellow birch (betula alleghaniensis), american beech (fagus grandifolia), and sugar maple (acer saccharum) naturally revegetating a site in the northern hardwood forest 5 years following a commercial whole-tree harvest. prior to the disturbance (i.e., the harvest) the site was codominated by american beech, sugar maple, and yellow birch, wh ... | 1990 | 28312780 |
| formation of cis-coniferin in cell-free extracts of fagus grandifolia ehrh bark. | american beech (fagus grandifolia ehrh) bark exclusively accumulates cis-monolignols and their glucosidic conjugates; no evidence for the accumulation of trans-monolignols has been found. the glucosyltransferase from this source exhibits a very unusual substrate specificity for cis, and not trans, monolignols. this is further evidence that cis monolignols are involved in lignin formation in these plant tissues. preliminary evidence for the existence of a novel trans-cis monolignol isomerase was ... | 1990 | 11537477 |
| exclusive accumulation of z-isomers of monolignols and their glucosides in bark of fagus grandifolia. | in addition to z-coniferyl and z-sinapyl alcohols, bark extracts of fagus grandifolia also contain significant amounts of the glucosides, z-coniferin, z-isoconiferin (previously called faguside) and z-syringin. the corresponding e-isomers of these glucosides do not accumulate to a detectable level. the accumulation of the z-isomers suggests that either they are not lignin precursors or that they are reservoirs of monolignols for subsequent lignin biosynthesis; it is not possible to distinguish b ... | 1988 | 11539000 |
| correlations of understory herb distribution patterns with microhabitats under different tree species in a mixed mesophytic forest. | this study examines the role of canopy trees in the formation and maintenance of different herb microhabitats in a mixed mesophytic forest stand. herb abundance and reproductive success were recorded in 54 circular plots under seven species of canopy trees and in 15 circular control plots>2 m from any tree. soil moisture, soil nutrient levels, litter depth, and light intensity were measured in a subset of these plots. ordination of plots by both herb relative abundance and by reproductive succes ... | 1984 | 28310886 |
| the lectin reactivity and lectin-like activity of allergenic pollen extracts. | the binding of soluble components of pollen grains to plant-stigma receptors can be inhibited by concanavalin a. this lectin-like activity of pollen components is important in the genetic control of plant reproduction. aqueous extracts of allergenic pollens also react with concanavalin a. agarose gel-diffusion precipitates were used to survey and characterize the ability of allergenic pollen extracts to react with concanavalin a and other lectins. concanavalin a alone precipitated with extracts ... | 1984 | 6425389 |
| dark opening of stomata in successional trees. | dark opening of stomata was found in shade intolerant tree species in three different sets of experiments. in the field, leaves of eight successional species were darkened in light-proof bags and leaf resistance measured with a diffusion porometer. white ash, quaking aspen and american beech were sampled more intensively using darkened cuvettes and a dew point hygrometer. in the lab, white ash seedlings were kept in constant darkness and temperature, and their leaves also monitored with a cuvett ... | 1982 | 28310395 |
| criconema proclivus n. sp. (nematoda: criconematinae) from woodlands. | criconema proclivis n. sp. from soil around roots of woodland trees in the northeastern usa is described and illustrated. it is characterized by a total of 67-74 annules, two naked offset head annules, a stylet length of 68.7 -80.7 mu, a sculpted vulval flap, and forward-projecting body annules. the annules at midbody are covered with a continuous fringe of 60-70 spines. | 1973 | 19319323 |
| first-year breakdown of leaf litter in southern appalachian forests. | breakdown of organic matter, an important step in the ecological circulation of chemical elements, was measured in great smoky mountain and oak ridge forests. greatest variation in first-year weight loss of leaves in nylon net bags was due to species (fagus grandifolia 21 percent, acer saccharum 32 percent, quercus shumardii 34 percent, quercus alba 39 percent, morus rubra 64 percent). at elevations of 5200, 3400, and 850 ft, losses for all five species averaged, respectively, 29, 34, and 40 per ... | 1961 | 17818719 |