| 136 | Martin, J.G., B.D. Kloeppel, T.L. Schaefer, D.L. Kimbler, and S.G. McNulty | 1998 | Aboveground biomass and nitrogen allocation of ten deciduous southern Appalachian tree species. | Martin, J.G., B.D. Kloeppel, T.L. Schaefer, D.L. Kimbler, and S.G. McNulty. 1998. Aboveground biomass and nitrogen allocation of ten deciduous southern Appalachian tree species. Canadian Journal of Forest Research. 28: 1648-1659. | Allometric equations were developed for mature trees of 10 deciduous species at the Coweeta Hydrologic Laboratory in western North Carolina, U.S.A. These equations included the following dependent variables: stem wood mass, stem bark mass, branch mass, total wood mass, foliage mass, total biomass, foliage area, stem surface area, sapwood volume, and total tree volume. High correlation coefficients (R2) were observed for all variables versus stem diameter, with the highest being for total tree biomass, which ranged from 0.981 for Oxdendrum arboreum to 0.999 for Quercus coccinea. Foliage area had the lowest R2 values, ranging from 0.555 for Quercus alba to 0.962 for Betula lenta. When all species were combined, correlation coefficients ranged from 0.822 for foliage area to 0.986 for total wood mass, total tree biomass, and total tree volume. Species with ring versus diffuse/semiring porous wood anatomy exhibited higher leaf area with a given cross-sectional sapwood area as well as lower total sapwood volume. Liriodendron tulipifera contained one of the highest foliar nitrogen concentrations and had consistently low branch, bark, sapwood, and heartwood nitrogen contents. For a tree diameter of 50 cm, Carya spp. exhibited the highest total nitrogen content whereas Liriodendron tulipifera exhibited the lowest.
| 188 | Kloeppel, B.D., S.T. Gower, I.W. Treichel, and S.Kharuk | 1998 | Foliar carbon isotope discrimination in Larix species and sympatric evergreen conifers: a global comparison. | Kloeppel, B.D., S.T. Gower, I.W. Treichel, and S.Kharuk. 1998. Foliar carbon isotope discrimination in Larix species and sympatric evergreen conifers: a global comparison. Oecologia 114: 153-159. | Larches (Larix spp.), deciduous conifers, occur in the northern hemisphere in cold-temperate and boreal climates - an environment normally thought to favor evergreen tree species. We compare foliar carbon isotope discrimination (D), instantaneous water-use efficiency, total foliar nitrogen concentration, and specific leaf area (for a subset of sites) between Larix spp. and co-occurring evergreen conifers at 20 sites throughout the natural range of larches. Except for Larix occidentalis in the xeric Intermountain West, USA, D is significantly (P < 0.05) greater for larches than co-occurring evergreen conifers at 77% of the sites, suggesting that larches use water less efficiently. At elevations greater than 3000 m, the D of Larix spp. and co-occurring conifers converge, suggesting that water is not the limiting resource. Foliar nitrogen concentration and specific leaf area are two ecophysiological characteristics that are positively correlated to high photosynthetic capacity. Foliar nitrogen concentration is significantly greater for larches than evergreen conifers at 88% of the sites and specific leaf area (SLA) is approximately three times greater for larches than co-occurring conifers. Future studies should examine the potential effect that global warming may have on the distribution of larch forests because the water-use efficiency of larches is commonly less than co-occurring evergreen conifers and the boreal and high-latitude environments are likely to experience the greatest climate warming.
| 1397 | Kloeppel, B.D., S.T. Gower, J.G. Vogel, and P.B. Reich | 2000 | Leaf-level resource use for evergreen and deciduous conifers along a resource availability gradient. | Kloeppel, B.D., S.T. Gower, J.G. Vogel, and P.B.Reich. 2000. Leaf-level resource use for evergreen and deciduous conifers along a resource availability gradient. Functional Ecology. 14: 281-292. | *We compared leaf-level carbon, nitrogen and water use for a deciduous (Larix occidentalis Nutt.) and sympatric evergreen (Pseudotsuga menziesii, Beissn., Franco, or Pinus contorta Engelm.) confer along a resource availability gradient spanning the natural range of L. occidentalis in western Montana, USA. * We hypothesized that leaf photosynthesis (A), respiration (r), specific leaf area (SLA) and foliar nitrogen concentration (N) would be higher for deciduous than sympatric evergreen conifers in mixed stands, and that these interspecies differences would increase from high to low resource availability. We also hypothesized that leaf-level nitrogen and water-use efficiency would be higher for the co-occurring evergreen conifer than L. occidentalis. *In general, mass-based photosynthesis (Am) was significantly higher for L. occidentalis than co-occurring evergreen conifers in the drier sites, but Am was similar for evergreen and deciduous conifers at the mesic site. *Mass-based foliar nitrogen concentration (Nm) was positively correlated to SLA for all species combined across the gradient (R2 = 0+64), but the relationship was very weak (R2 = 0+08v 0+34) for evergreen and deciduous species separately. Mass-based Am and rm were poorly correlated to Nm for all species combined across the gradient (R2 = 0+28 and 0+04, respectively). *For each site-species combination, daily maximum Am was negatively correlated to vapour pressure deficit (VPD) (R2 < 0+04). *Instantaneous nitrogen-use efficiency (NUEi; Am divided by Nm) and water-use efficiency (13C) increased significantly (P = 0+05) from high to low resource availability for both evrgreen and deciduous conifers, except for NUEi in L. occidentalis.
| 2000 | Yeakley, J.A., D.C. Coleman, B.L. Haines, B.D. Kloeppel, J.L. Meyer, W.T. Swank, B.W. Argo, J.M. Deal, and S.F. Taylor | 2003 | Hillslope nutrient dynamics following upland riparian vegetation disturbance. | Yeakley, J.A., D.C. Coleman, B.L. Haines, B.D. Kloeppel, J.L. Meyer, W.T. Swank, B.W. Argo, J.M. Deal, and S.F. Taylor. 2003. Hillslope nutrient dynamics following upland riparian vegetation disturbance. Ecosystems. 6(2): 154-167. | We investigated the effects of removing near-stream Rhododendron and of the natural blowdown of canopy trees on nutrient export to streams in the southern Appalachians. Transects were instrumented on adjacent hillslopes in a first-order watershed at the Coweeta Hydrologic Laboratory (35degrees03'N, 83degrees25'W). Dissolved organic carbon (DOC), K+, Na+, Ca2+, Mg2+, NO3--N, NH4+-N, PO43--P, and SO42- were measured for 2 years prior to disturbance. In August 1995, riparian Rhododendron on one hillslope was cut, removing 30% of total woody biomass. In October 1995, Hurricane Opal uprooted nine canopy trees on the other hillslope, downing 81% of the total woody biomass. Over the 3 years following the disturbance, soilwater concentrations of NO3--N tripled on the cut hillslope. There were also small changes in soilwater DOC, SO42-, Ca2+, and Mg2+. However, no significant changes occurred in groundwater nutrient concentrations following Rhododendron removal. In contrast, soilwater NO3--N on the storm-affected hillslope showed persistent 500-fold increases, groundwater NO3--N increased fourfold, and streamwater NO3--N doubled. Significant changes also occurred in soilwater pH, DOC, SO42-, Ca2+, and Mg2+. There were no significant changes in microbial immobilization of soil nutrients or water outflow on the storm-affected hillslope. Our results suggest that Rhododendron thickets play a relatively minor role in controlling nutrient export to headwater streams. They further suggest that nutrient uptake by canopy trees is a key control on NO3--N export in upland riparian zones, and that disruption of the root-soil connection in canopy trees via uprooting promotes significant nutrient loss to streams.
| 2011 | Kloeppel, B.D., B.D. Clinton,J.M. Vose, and A.R. Cooper | 2003 | Drought impacts on tree growth and mortality of southern Appalachian forests. | Kloeppel, B.D., B.D. Clinton,J.M. Vose, and A.R. Cooper. 2003. Drought impacts on tree growth and mortality of southern Appalachian forests, pp. 43-55. In Greenland, D., D.G. Goodin, and R.C. Smith (eds.), Climate variability and ecosystem response at long-term ecological research sites. Oxford University Press, New York, NY. | In this chapter, we describe the general climate and physical and biological features of Coweeta as well as the impact of drought on tree growth and mortality. In particular, we focus on data from the 1985 to 1988 and 1998 to 2001 drought periods at Coweeta. We also describe the drought impacts on tree growth rates, tree mortality caused by southern pin beetle, tree mortality caused by pathogens, interactions with tree insects and diseases, and tree species-specific mortality. These impacts are summarized in a description of drought as a disturbance regime. The timescale of this climate variability is annual with the potential for preexisting soil moisture conditions either providing a buffer or further exacerbating the drought conditions.
| 2256 | Knoepp, J.D., J.M. Vose, K.J. Elliott, B.D. Clinton, C.R. Ford, and B.D. Kloeppel | 2005 | Hemlock Woolly Adelgid Research at the Coweeta Hydrologic Laboratory. | Knoepp, J.D., J.M. Vose, K.J. Elliott, B.D. Clinton, C.R. Ford, and B.D. Kloeppel. 2005. Hemlock Woolly Adelgid Research at the Coweeta Hydrologic Laboratory. In Proceedings, Save our hemlocks third symposium on hemlock woolly adelgid in the eastern United States. | Hemlock woolly adelgid (HWA) is a non-native invasive pest that impacts eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana). Hemlock trees serve important ecological roles in the southern Appalachians as a keystone species in near-stream areas. Scientists at the USDA Forest Service, Coweeta Hydrologic Laboratory and their collaborators have established studies to examine the function of hemlock in riparian areas and the effects of its potential demise through the activity of HWA. We have focused our research activities in four areas; mapping and monitoring, effects, control, and restoration. Utilizing permanent vegetation plots, established in the Coweeta basin in 1934, we can map the extent and monitor the progress of HWA infestation and its effects on plant biodiversity. We have established intensive research plots to measure the effects of infestation on terrestrial and aquatic nitrogen and carbon cycling, forest and stream microclimatology, site productivity, and plant physiology. Future research will explore methods to restore ecosystem function in areas where hemlock is or will be heavily impacted by HWA. Of particular interest is restoring the function of hemlock in terms of providing critical habitat for birds and other animals, shading streams to maintain water temperatures required by trout and other aquatic organisms, and regulating nutrient, carbon and water pools and fluxes.
| 2293 | Ellison, A.M., M.S. Bank, B.D. Clinton, E.A. Colburn, K. Elliott, C.R. Ford, D.R. Foster, B.D. Kloeppel, J.D. Knoepp, G.M. Lovett, J. Mohan, D.A. Orwig, N.L. Rodenhouse, W.V. Sobczak, K.A. Stinson, J.K. Stone, C.M. Swan, J. Thompson, and B. Von | 2005 | Loss of foundation species: consequences for the structure and dynamics of forested ecosystems. | Ellison, A.M., M.S. Bank, B.D. Clinton, E.A. Colburn, K. Elliott, C.R. Ford, D.R. Foster, B.D. Kloeppel, J.D. Knoepp, G.M. Lovett, J. Mohan, D.A. Orwig, N.L. Rodenhouse, W.V. Sobczak, K.A. Stinson, J.K. Stone, C.M. Swan, J. Thompson, and B. Von. 2005. Loss of foundation species: consequences for the structure and dynamics of forested ecosystems. Frontiers in Ecology and the Environment. 3: 479-486. | In many forested ecosystems, the architecture and functional ecology of certain tree species define forest structure and their species-specific traits control ecosystem dynamics. Such foundation tree species are declining throughout the world due to introductions and outbreaks of pests and pathogens, selective removal of individual taxa, and over-harvesting. Through a series of case studies, we show that the loss of foundation tree species changes the local environment on which a variety of other species depend; how this disrupts fundamental ecosystem processes, including rates of decomposition, nutrient fluxes, carbon sequestration, and energy flow; and dramatically alters the dynamics of associated aquatic ecosystems. Forests in which dynamics are controlled by one or a few foundation species appear to be dominated by a small number of strong interactions and may be highly susceptible to alternating between stable states following even small perturbations. The ongoing decline of many foundation species provides a set of important, albeit unfortunate, opportunities to develop the research tools, models, and metrics needed to identify foundation species, anticipate the cascade of immediate, short- and long-term changes in ecosystem structure and function that will follow from their loss, and provide options for remedial conservation and management.
| 3049 | Kloeppel, B.D., M.E. Harmon, and T.J. Fahey | 2007 | Estimating aboveground net primary productivity in forest-dominated ecosystems. | Kloeppel, B.D., M.E. Harmon, and T.J. Fahey. 2007. Estimating aboveground net primary productivity in forest-dominated ecosystems, pp.63-81. In Fahey, T.J., and A.K. Knapp (eds.), Principles and Standards for Measuring Primary Production. Oxford University Press, New York, NY. | The measurement of net primary productivity (NPP) in forest ecosystems presents a variety of challenges because of the large and complex dimensions of trees and the difficulties of quantifying several components of NPP. As summarized by Clark et al. (2001a), these methodological challenges can be overcome, and more reliable spatial and temporal comparisons can be provided, only if greater conceptual clarity and more standardized approaches to the problem are achieved. The objective of this chapter is to contribute to correction of these limitations in forest NPP measurement. Because Clark et al. (2001a) did an exemplary job with this topic, our task is made somewhat easier. We focus our attention on a variety of practical matters concerning field measurements and calculations for aboveground NPP in broadleaf deciduous, evergreen coniferous, and tropical forest biomes. We evaluate the advantages and disadvantages of contrasting approaches to key measurements and provide recommendations that should aid researchers in designing field campaigns.
| 3054 | Oleksyn, J., B.D. Kloeppel, S. Lukasiewicz, P. Karolewski, and P.B. Reich | 2007 | Ecophysiology of horse chestnut (Aseculus Hippocastanum L.) in degraded and restored urban sites. | Oleksyn, J., B.D. Kloeppel, S. Lukasiewicz, P. Karolewski, and P.B. Reich. 2007. Ecophysiology of horse chestnut (Aseculus Hippocastanum L.) in degraded and restored urban sites. Polish Journal of Ecology. 55(2): 245-260. | We explored changes in growth, phenology, net CO2 assimilation rate, water use efficiency, secondary defense compounds, substrate and foliage nutrient concentration of a degraded urban horse chestnut (Aseculus hippocastanum L.) site restored for three years using mulching (tree branches including foliage) and fertilization (primarily nitrogen addition). Prior to restoration, this site was characterized by high pH (ca.8), low foliage and substrate N, and high Na and C1 concentration. Our data indicated that in untreated plots NaC1 used for road deicing is the decisive factors that may be responsible for the decrease of foliar N concentration (via a reduction in NO3-uptake), for the decrease in photosynthesis (through high concentrations of Na and C1 in the leaves) and for increased senescence of the leaves. After three years of treatment, total nitrogen concentration in substrate increased by 3- to 4- fold and calcium concentration decreased by more than 50% in relation to pretreatment levels. Treatment significantly increased seed production (from less than 12 to more than 100 seeds per tree), individual leaf mass (from 1.8 to 3.3 g/leaf), CO2 assimilation rate (by 21 to 30%), improved leaf C:N ration, and increased foliage life span by as much as six weeks. The beginning of leaf fall in untreated control trees started in mid-July and those of mulched and fertilized trees in late October. Applied treatment also eliminated visible symptoms of leaf damage due to high sodium and chlorine levels, indicating the possible role of other factors in the development of necroses. After three years of treatment, pH of most degraded plots declined from 8.2 to 7.8. That decline was accompanied by an increase in foliar Zn, Cu, and Pb concentration in the mulched and fertilized plants. In addition, treatment lowered foliage phenolics making these plants potentially more vulnerable to insect herbivory. Our study indicates that stable carbon isotope discrimination is of little value as an indicator of cumulative salinity and urban environment stress in A. hippocastanum due to pronounced differences in leaf phenology and ontogeny. The results of our study show that street tree recovery can take as little as two to three years after application of fertilization and mulching.
| 3062 | Ford, C.R., R.M. Hubbard, B.D. Kloeppel, and J.M. Vose | 2007 | A comparison of sap flux-based evapotranspiration estimates with catchment-scale water balance. | Ford, C.R., R.M. Hubbard, B.D. Kloeppel, and J.M. Vose. 2007. A comparison of sap flux-based evapotranspiration estimates with catchment-scale water balance. Agricultural and Forest Meteorology. 145: 176-185. | Many researchers are using sap flux to estimate tree-level transpiration, and to scale to stand- and catchment-level transpiration; yet studies evaluating the comparability of sap flux-based estimates of transpiration (Et) with alternative methods for estimating Et at this spatial scale are rare. Our ability to accurately scale from the probe to the tree to the watershed has not yet been demonstrated, nor do we know the relative impact of the main sources of variability on our scaled estimates. Accounting for the variability in the radial distribution of sap flux within the sapwood, the variability of transpiration among trees and between plots within the catchment, and the variability in stand density, sapwood area, and leaf area are critical for making landscape inferences about transpiration. During 2004 and 2005, we continuously monitored 40 trees in three plots within a 13.5-ha gauged watershed comprising a 50-year-old eastern white pine plantation within the Coweeta Basin in western North Carolina, USA. We scaled sap flux-based estimates of stand transpiration (Et) and surface area-based estimates of stand interception (Ei) to the catchment and compared these with water balance estimates of evapotranspiration (E, precipitation minus runoff, P Ro). For both years, the sum of sap flux scaled Et and Ei were 14 and 7% lower that evapotranspiration estimated from P Ro. Our results show that a considerable amount of variation exists at each scaling step encountered; however, a simple scaling exercise revealed that omitting among plot variation affected the sap flux scaled Et estimate by 48%. Thus, the largest source of variability in scaling to the landscape was landscape variation in stand density and sapwood area.
| 3076 | Clark, J.S., M. Wolosin, M. Dietze, I. Ibanez, S. LaDeau, M. Welsh, and B. Kloeppel | 2007 | Tree growth inference and prediction from diameter censuses and ring widths. | Clark, J.S., M. Wolosin, M. Dietze, I. Ibanez, S. LaDeau, M. Welsh, and B. Kloeppel. 2007. Tree growth inference and prediction from diameter censuses and ring widths. Ecological Applications 17(7): 1942-1953. | Estimation of tree growth is based on sparse observations of tree diameter, ring widths, or increments read from a dendrometer. From annual measurements on a few trees (e.g., increment cores) or sporadic measurements from many trees (e.g., diameter censuses on mapped plots), relationships with resources, tree size, and climate are extrapolated to whole stands. There has been no way to formally integrate different types of data and problems of estimation that result from (1) multiple sources of observation error, which frequently result in impossible estimates of negative growth, (2) the fact that data are typically sparse (a few trees or a few years), whereas inference is needed broadly (many trees over many years), (3) the fact that some unknown fraction of the variance is shared across the population, and (4) the fact that growth rates of trees within competing stands are not independent. We develop a hierarchical Bayes state space model for tree growth that addresses all of these challenges, allowing for formal inference that is consistent with the available data and the assumption that growth is nonnegative. Prediction follows directly, incorporating the full uncertainty from inference with scenarios for ‘‘filling the gaps’’ for past growth rates and for future conditions affecting growth. An example involving multiple species and multiple stands with tree-ring data and up to 14 years of tree census data illustrates how different levels of information at the tree and stand level contribute to inference and prediction.
| 4015 | Beckage, B., B.D. Kloeppel, J.A. Yeakley, S.F. Taylor, and D.C. Coleman | 2008 | Differential effects of understory and overstory gaps on tree regeneration. | Beckage, B., B.D. Kloeppel, J.A. Yeakley, S.F. Taylor, and D.C. Coleman. 2008. Differential effects of understory and overstory gaps on tree regeneration. Journal of the Torrey Botanical Society. 135(1):1-11. | Gaps in the forest canopy can increase the diversity of tree regeneration. Understory shrubs also compete with tree seedlings for limited resources and may depress tree recruitment. We compared effects of shrub removal and canopy windthrow gaps on seedling recruitment and understory resource levels.
| 10322 | April E. Nuckolls, Nina Wurzburger, Chelcy R. Ford, Ronald L. Hendrick, James M. Vose, and Brian D. Kloeppel | 2009 | Hemlock Declines Rapidly with Hemlock Woolly Adelgid Infestation: Impacts on the Carbon Cycle of Southern Appalachian Forests | Nuckolls, April E.; Wurzburger, Nina; Ford, Chelcy R.; Hendrick, Ronald L.; Vose, James M.; Kloeppel, Brian D. 2009. Hemlock declines rapidly with hemlock woolly adelgid infestation: impacts on the carbon cycle of southern Appalachian forests. Ecosystems. 12: 179-190. | The recent infestation of southern Appalachian eastern hemlock stands by hemlock woolly adelgid (HWA) is expected to have dramatic and lasting effects on forest structure and function. We studied the short-term changes to the carbon cycle in a mixed stand of hemlock and hardwoods, where hemlock was declining due to either girdling or HWA infestation. We expected that hemlock would decline more rapidly from girdling than from HWA infestation. Unexpectedly, in response to both girdling and HWA infestation, hemlock basal area increment (BAI) reduced substantially compared to reference hardwoods in 3 years. This decline was concurrent with moderate increases in the BAI of co-occurring hardwoods. Although the girdling treatment resulted in an initial pulse of hemlock needle inputs, cumulative litter inputs and O horizon mass did not differ between treatments over the study period. Following girdling and HWA infestation, very fine root biomass declined by 20–40% in 2 years, which suggests hemlock root mortality in the girdling treatment, and a reduction in hemlock root production in the HWA treatment. Soil CO2 efflux (E soil) declined by approximately 20% in 1 year after both girdling and HWA infestation, even after accounting for the intra-annual variability of soil temperature and moisture. The reduction in E soil and the concurrent declines in BAI and standing very fine root biomass suggest rapid declines in hemlock productivity from HWA infestation. The accelerated inputs of detritus resulting from hemlock mortality are likely to influence carbon and nutrient fluxes, and dictate future patterns of species regeneration in these forest ecosystems.
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Showing results 1 to 13 of 13 Coweeta Publications: PI's: Kloeppel.
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