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This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Dk2 Duke Forest-hardwoods. This is the FLUXNET version of the carbon flux data for the site US-Dk2 Duke Forest-hardwoods produced by applying the standard ONEFlux (1F) software. Site Description - private land adjacent to the Duke Forest in November 2002
The mixed hardwood and conifer forests of northern Michigan were overflown by a 3-frequency airborne imaging radar in Apr. and Jul. 1990. A set of 10 x 10 km test sites near the University of Michigan Biological Station at Douglas Lake and within the Hiawatha National Forest in the upper peninsula of Michigan contained training stands representing the various forest species typical of forest communities across the ecotone between the coniferous boreal forest and mid-latitude hardwood and coniferous forests. The polarimetric radar data were externally calibrated to allow interdate comparisons. The Apr. flight was prior to bud-break of deciduous species and patchy snowcover was present. The Jul. flights occurred during and 2 days after heavy rain showers, and provide a unique opportunity to examine the differences in radar backscatter attributable to intercepted precipitation. Analyses show that there are significant changes in backscattering between biophysically dissimilar forest stands on any given date and also between dates for a given forest stand. These differences in backscattering can be related to moisture properties of the forest floor and the overlying canopy and also to the quantity and organizational structure of the above-ground biomass.
This is the AmeriFlux version of the carbon flux data for the site US-PFm SW3 Hardwood-2 CHEESEHEAD 2019. Site Description - This tower (32m, trailer-based, telescoping) is located in the southwestern quadrant of the 10 x 10km study domain. It is located in an aspen and maple forest (canopy height: 15 m).
Past estimates of CH4 fluxes from forested swamps ranged from 10 to 106 mg C m-2 d-1 in temperate regions and 44 to144 mg C m-2 d-1 in subtropical and tropical regions. However, climate change could alter these rates in wetlands where efflux is predominantly controlled by water level, temperature, and plant composition. While the Lower Mississippi Alluvial Valley has experienced the largest loss of forested wetlands in the U.S, supporting 21 to 25 million acres of bottomland hardwoods before European settlement, an estimated 5 million acres remain. This landscapes remain under-studied from a CH4 flux perspective, particularly in determining woody vegetation contributions to landscape CH4 emissions. Our overarching objective are to (1) improve our understanding of the controls on CH4 fluxes in forested mineral soil wetlands, and (2) to better understand the effects of landscape position and forest composition on the CH4 fluxes between terrestrial ecosystems and the atmosphere. Our main goal is to elucidate the
In a study of hardwood forests in Pennsylvania, the detection of clearcuts by means of visual analysis of Landsat summer imagery was accomplished best using band 5 images; however, a higher percentage of clearcuts could be detected using bands 5 or 7 winter images acquired during periods of snow cover.
A hand-held radiometer with AVHRR bands 1 and 2 was used to measure the directional reflectance distributions for both a hardwood and a pine forest canopy from a helicopter platform; canopy characteristics were also measured on the ground. The reflectance distributions obtained are compared with the scattering behavior of agricultural and natural grassland canopies. In addition, the Kimes (1983) three-dimensional radiative transfer model is used to document the unique radiant transfers that occur in forest canopies in virtue of their geometric structure. Both the measurements and the model calculations show that dense forest canopy scattering is similar to that for crops and grasslands. Attention is given to the effects of sparse forest canopies.
The unique directional scattering properties of a deciduous hardwood forest without leaves during the winter period was measured in a visible and near-infrared band. A radiative transfer model was used to explore the scattering properties of such a forest. The reflectance distributions look similar to sparse homogeneous vegetation canopies. The overall reflectance distribution is a combination of the extreme azimuthal scattering behavior of tree limbs and the more typical scattering behavior of understory litter.
The invasive, herbivorous insect Lymantria dispar is a major defoliator of hardwood trees in the northeastern United States. Established populations of L. dispar typically rest at low levels but undergo recurring outbreaks that cause tree mortality if they occur in quick succession or are combined with other stressors on tree health. Widespread defoliation events disrupt local wildlife, economies, and livelihoods. Accurate monitoring of defoliation events is necessary to implement effective land management practices that support tree health. There are challenges to accurately monitoring L. dispar outbreaks that include the ephemeral character of defoliation disturbances and the difficulties of conducting large-scale surveys of L. dispar populations using existing aerial and ground-based data collection methods. To better monitor the impact of L. dispar on forests in Vermont and New Hampshire, the NASA DEVELOP team partnered with organizations responsible for supporting land and invasive species management including the Forest Ecosystem Monitoring Cooperative, the Vermont Agency of Agriculture, Food and Markets, the University of New Hampshire Cooperative Extension, and the New Hampshire Division of Forests and Lands, Forest Health Program. The team used NASA Earth observations collected by the Terra, Soil Moisture Active Passive (SMAP), Shuttle Radar Topography Mission (SRTM), Landsat 7, and Landsat 8 satellites along with ancillary datasets to map historical tree defoliation from 2012 to 2021. In support of partners’ future land management efforts, the team created a Google Earth Engine tool that displays annual defoliation extent.
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Abstract Biogenic volatile organic compounds (bVOCs) play important roles in ecological interactions and Earth system processes, yet the biological and physical processes that drive soil bVOC exchanges remain poorly understood. In temperate forests, nearly all tree species associate with arbuscular mycorrhizal (AM) or ectomycorrhizal (ECM) fungi. Given well‐established differences in soil biogeochemistry between AM‐dominated and ECM‐dominated stands, we hypothesized that bVOC exchanges with the atmosphere would differ between soils from the two stand types. We measured bVOC fluxes at the soil‐atmosphere interface in plots dominated by AM‐ and ECM‐associated trees in a deciduous forest in south‐central Indiana, USA during the early and late vegetative growing season. Soils in both AM‐ and ECM‐dominated plots were a net bVOC sink following leaf‐out and were a greater bVOC sink or smaller source at warmer soil temperatures ( T s ). The flux of different bVOCs from ECM plots was often related to soil water content in addition to T s . Methanol dominated total bVOC fluxes, and ECM soils demonstrated greater uptake relative to AM‐dominated plots, on the order of 170 nmol m −2 hr −1 during the early growing season. Our results demonstrate the importance of soil dynamics characterized by mycorrhizal associations to bVOC dynamics in forested ecosystems and emphasize the need to study bidirectional soil bVOC uptake and emission processes.
Volatile products from thermal decomposition of lignocellulosic biomass have been well characterized, but the solid- and liquid-phase reactions during the early stages of decomposition are largely unknown. Here the initial solid-phase biomass thermal deconstruction reactions were analyzed in situ and with high particle heating rates, delineating how these processes occur. A variety of instrumentation was used to quantify the extent and relative rates of deconstruction, demonstrating that biopolymers resist the thermally energetic conditions to differing degrees, even when ensconced in biomass cell walls. Hemicellulose and the more frangible lignin components decompose and volatilize more readily than cellulose, which temporarily enriches biomass with cellulose. These chemical changes manifest in larger cell wall structural and mechanical property transformations. In all, this investigation concludes that these solid-phase reactions strongly influence the production rates of volatile species and will require additional study before these processes can be modeled precisely to improve yields of desired product.
Manual photointerpretation techniques were used to analyze images acquired by high altitude aircraft, the Skylab multispectral and Earth terrain camera (ETC), the LANDSAT multispectral scanner, and the LANDSAT-3 return beam vidicon camera. A color-additive viewer, and digital image analysis were also used on the LANDSAT MSS imagery. The value of each type of remotely sensed data was judged by the ease and accuracy of clearcut identification, and by the amount of detail discernible, especially regarding revegetation. Results of a site study in the Allegheny National Forest, Pennsylvania indicate that high altitude aerial photography, especially color infrared photography acquired during the growing season, is well suited for identifying clearcuts and assessing revegetation. Although photographs acquired with Skylab's ETC also yielded good results, only incomplete inventories of clearcuts could be made using LANDSAT imagery. Results for the Adirondack region of New York State were similar for the aircraft and satellite photography, but even less satisfactory for the LANDSAT imagery.
An automated system for conducting annual gypsy moth defoliation surveys using LANDSAT MSS data and digital processing techniques is described. A two-step preprocessing procedure was developed that uses multitemporal data sets representing forest canopy conditions before and after defoliation to create a digital image in which all nonforest cover types are eliminated or masked out of a LANDSAT image that exhibits insect defoliation. A temporal window for defoliation assessment was identified and a statewide data base was established. A data management system to interface image analysis software with the statewide data base was developed and a cost benefit analysis of this operational system was conducted.
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The frequency, scale, and severity of wildfires are steadily increasing in the Western United States. Sustainable forest management practices through forest thinning could reduce the impact of wildfires and provide lumber for wood-based, long-lived, and low-carbon building materials. This study explores the potential for harvesting biomass in California (CA) to mitigate wildfire risk and provide multi-decade carbon storage in the form of cross-laminated timber (CLT) for use in buildings. First, we assessed biomass resource availability, finding that the total live hardwood and live softwood available in the wildland-urban interfaces (WUIs) across CA sums to 14.1 million metric tons (MMT) and 34.9 MMT, respectively, which contains the equivalent of 90 MMT of atmospheric carbon dioxide. Then, we conducted a life cycle assessment of CLT considering softwood and hardwood sources to provide insights into emissions and energy demand associated with utilization of the wood removed for wildfire risk management. We found that the net life cycle carbon footprint of live hardwood and softwood when including biogenic carbon storage/emissions is 414 and 317 kg CO2e/m3 CLT, respectively. To incorporate the timing of these emissions and uptake, we have also conducted a cradle-to-grave time-dependent global warming potential (GWP) analysis. The time-adjusted GWP for live hardwood and live softwood is −227 and −104 kg CO2e/m3 CLT, respectively. In terms of total CLT production potential, 0.03 and 0.005 million m3 CLT can be sourced from live softwood and hardwood, respectively, in WUI on gentle slopes in CA. The resulting insights and approaches from this study are broadly applicable to other forested regions and WUIs across the US and the world, and provide a holistic approach to use forest thinning as a wildfire mitigation strategy in combination with a novel approach for life cycle assessment of building materials with a limited dataset.
Conservation of endangered social wildlife in disturbance-prone forests is challenging because direct and indirect effects of management strategies developed at the time of species’ listing when population density is low may change under high-density conditions in locally recovered populations. Here, we used piecewise structural equation modeling to evaluate direct and indirect drivers of productivity in the federally endangered cooperatively breeding red-cockaded woodpecker Dryobates borealis (RCW) on Savannah River Site, South Carolina, USA. We estimated direct and indirect relationships among group size, neighboring group sizes, fledgling production, density of cavity tree clusters occupied by RCWs, area satisfying threshold criteria of ≥22 stems ha –1 of pines ≥35.6 cm diameter at breast height (dbh), <1.4 m 2 ha –1 basal area (BA) of hardwoods 7.6–22.9 cm dbh, and <6% hardwood canopy cover, and area treated with prescribed fire, and tested whether group size mediated indirect effects of area satisfying threshold criteria on fledgling production. Increases in area with ≥22 stems ha –1 of pines ≥35.6 cm dbh and <1.4 m 2 ha –1 BA of hardwoods 7.6–22.9 cm dbh, and area treated with prescribed fire, but not area with <6% hardwood canopy cover, had direct positive effects on group size. Group size and area treated with prescribed fire, but not area satisfying threshold criteria, had direct positive effects on fledgling production. The direct effect of neighboring group sizes on fledgling production was negative and smaller relative to the direct positive effect of group size on fledgling production. Overall, our results indicate positive direct effects of group size on fledgling production outweighed negative direct effects of neighboring group sizes, and that group size mediated positive indirect effects of area satisfying structural threshold criteria on fledgling production. These findings indicate that ongoing forest management aimed to increase area with ≥22 pines ha –1 ≥35.6 cm dbh and <1.4 m 2 ha –1 BA of hardwoods 7.6–22.9 cm dbh will promote large group sizes, which in turn improve fledgling production and offset costs of heightened competition with neighboring groups under high-density conditions. Additionally, positive effects of area treated with prescribed fire on RCW group size and fledgling production indicate prescribed fire has unique contributions to woodpecker productivity, likely via direct effects on forest structure and potentially indirect effects on arthropod prey available to foraging RCWs. Furthermore, by simultaneously accounting for multiple drivers of productivity in social wildlife, our study contributes to the understanding of how increases in social wildlife population sizes can alter previously documented habitat-fitness relationships.