Treesearch

Shifts in phenological timing have important implications for ecosystem processes, with spring leaf emergence as a dominant control of carbon, water, and energy cycling. Phenological events are predominantly determined by weather and climate, therefore dynamic in time and sensitive to climate feedbacks. Improving our understanding of how ecosystems respond to changes in phenological timing will enhance our ability to assess summer soil water availability, since the timing of spring leaf emergence may lead to soil moisture deficits later in the growing season. We leveraged data from five...

The South’s production of pulpwood increased from 57.0 million cords in 2020 to 59.0 million cords in 2021. Roundwood production increased by 1.8 million cords to 44.2 million cords and accounted for 75 percent of the South’s total pulpwood production. The use of wood residue increased 1 percent to 14.7 million cords in 2021. Alabama and Georgia led the South in total production, with 9.6 and 9.3 million cords, respectively. In 2021, 73 mills were operating and drawing wood from the 13 Southern States.

For the existence of biorefineries, a consistent supply of sustainable crop residues is critical. Crop residue removal may adversely affect the overall sustainability, i.e., soil productivity and economics of crop residue removal. Therefore, it is necessary to develop a tool or method to estimate the sustainable removal of crop residues which is critical to various stakeholders including farmers, biorefinery, and policymakers. We proposed a robust deep ensemble machine learning(ML) model to estimate soil sustainability indicators [i.e., soil-erosion-factor(SEF), soil-conditioning-index(SCI)...

As a signatory to the United Nations Framework Convention on Climate Change (UNFCCC), the United States has reported an inventory of greenhouse gas (GHG) emissions and removals by sector, as defined by the Intergovernmental Panel on Climate Change (IPCC), since the mid-1990s (U.S. EPA 2023). In 2021, United States net GHG emissions increased by more than 6.8 percent relative to 2020 net emissions, which had decreased substantially from previous years and was due, in large part, to the global pandemic. Forest land, harvested wood products (HWP), woodlands, and urban trees within the land...

Increasing demand for bioenergy from intensively managed woody crops raises concerns of increased evapotranspiration and potential decreases in water yield. Pinus taeda (loblolly pine) is currently the most cultivated species in the southeastern USA, the country’s wood basket. However, Eucalyptus species could achieve greater productivity but with unknown ramifications for water budgets. To address the knowledge gap, we determined annual water budgets of loblolly pine and Eucalyptus benthamii (eucalypt) from growing years 3 through 5 in a replicated (n = 3) two-factor design comparing...

The alligator snapping turtle (Macrochelys temminckii) is a long-lived species that is widely distributed across the southeastern United States. Both these characteristics make monitoring its occupancy and abundance particularly challenging. In 2020 and 2021, we conducted hoop trap surveys at 51 permanent water bodies across the Texas, USA, range of the species to estimate occupancy and average abundance with site occupancy models and multinomial N‐mixture models, respectively. We confirmed the species to be present at 61% of surveyed locations. Mean detection probability was 0.77, and was...

Western pine beetle (Dendroctonus brevicomisLeConte) is a major cause of ponderosa pine (Pinus ponderosaDougl. ex. Laws.) mortality in western North America. Twenty-first century epidemics are among the largest in history and have affected hundreds of thousands of hectares. We synthesize literature on the chemical ecology of western pine beetle and on efforts to exploit our understanding of the western pine beetle-ponderosa pine system to reduce host tree losses. This literature dates back to the early 20th century and focuses on populations in California and Oregon, U.S., where western...

The continuity and depth of litter fuelbeds are major drivers of fire spread and fuel consumption. However, no established approach is available for the spatially explicit prediction of litter loads over large areas. Local fuel heterogeneity introduces large uncertainties on estimates derived from field-based models based on the extrapolation of sparse data samples. In fire-maintained pine forests of the southeastern US, litter accumulation and its distribution over the forest floor are mainly driven by vegetation productivity and by the number of years since the last fire (YSF). Some...

Most studies of land use effects on solute concentrations in streams have focused on smaller streams with watersheds dominated by a single land-use type. Using land cover as a proxy for land use, the objective of this study was to determine whether the hydrologically-driven response of solutes to land use in small streams could be scaled up to predict concentrations in larger receiving streams and rivers in the rural area of the Little Tennessee River basin. We measured concentrations of typically limiting nutrients (nitrogen, phosphorus), abundant anions (chloride, sulfate), and base...

The vertical source-sink distribution of air pollutants within and above forested canopies is necessary for describing the biological, physical, and chemical processes influencing the soil-vegetation-atmosphere exchange. This study implemented inverse modeling methods to estimate the source-sink and flux profiles of reactive nitrogen (N) and sulfur (S) compounds from measurements of the mean concentration profiles of ammonia (NH3), nitric acid (HNO3), sulfur dioxide (SO2), and particulate ammonium (NH4+), nitrate (NO3−), and sulfate (SO42−) at a forest site in the southern Appalachian...