Treesearch

This research analyzed two datasets to determine the effects of increased installations of biomass power plants on forest resources with a specific focus on the South, the region in the United States that experienced the largest growth in biomass power capacity using wood solids between 2001 and 2015. Using data from the U.S. Energy Information Administration and the U.S. Department of Agriculture Forest Service, effects on timber harvest and residue production and utilization relative to the increased need for wood fiber from new biomass power plants were assessed. The study found a...

This resource update provides an overview of the forest resources of Oklahoma based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station (SRS), and Oklahoma Forestry Services (OFS). Data collection and estimates are based on the FIA annualized sample design, and are updated yearly, creating a moving average. The 2016 resource update highlights how the moving average has been updated since the 2015 report (Dooley, 2017). The data used in this publication were accessed from the FIA Database between May 1 and June...

Atmospheric deposition of nitrogen (N) influences forest demographics and carbon (C) uptake through multiple mechanisms that vary among tree species. Prior studies have estimated the effects of atmospheric N deposition on temperate forests by leveraging forest inventory measurements across regional gradients in deposition. However, in the United States (U.S.), these previous studies were limited in the number of species and the spatial scale of analysis, and did not include sulfur (S) deposition as a potential covariate. Here, we present a comprehensive analysis of how tree growth and...

Hundreds of plant and fungi species (chapter 2) are harvested each year for nontimber forest products (NTFPs) because they play important roles in the cultural (chapter 4), social (chapter 5), and economic (chapter 6) lives of individuals and communities across the United States. Most of these species are harvested from natural populations, where they play important ecological roles, including providing food, cover, and habitat for diverse wildlife, including pollinators, and contribute to nutrient cycling, hydrological cycles, and erosion control. The continued use of NTFPs is contingent...

Traditional silvicultural systems such as clearcutting and single-tree selection cutting are critiqued for their tendency to simplify forest complexity. By more closely emulating natural disturbance regimes and increasing the availability and heterogeneity in understory light levels, we pose that systems causing intermediate disturbances such as the single-tree and small group selection cutting system can promote tree regeneration, retain stand structural attributes, and maintain high understory plant diversity in temperate mixedwood stands. To assess this, we implemented a harvest...

(1) Background: Climate change may subject forests to climate conditions to which they are not adapted. Elevated temperatures can potentially reduce net photosynthesis by increasing respiration rates and increasingly long droughts dramatically increase morbidity. While CO2 enrichment enhances productivity, it is not clear to what extent CO2 enrichment can offset the negative effects of elevated temperatures and longer droughts; (2) Methods: We used a mechanistic landscape model to conduct controlled simulation experiments manipulating CO2 concentration, temperature, drought length and soil...

The interplay of past management practices, higher temperatures, extended drought, and insectoutbreaks has resulted in unprecedented levels of tree mortality across the southern Sierra Nevada Mountains ofCalifornia. To characterize patterns in tree mortality, we collected repeated forest measurements on 255 variableradiusplots during 2015 and 2016. From initial measurements in spring 2015, sugar pine (Pinus lambertiana) andponderosa pine (P. ponderosa) mortality increased from 30 percent to 80 percent by summer 2016. Incense cedar(Calocedrus decurrens) mortality remained relatively stable...

In this experiment, 15N-labelled fertilizers were used to trace nitrogen uptake, assimilation, and fate in four loblolly pine (Pinus taeda) stands fertilized with 224 kg ha-1 of elemental nitrogen (N) in the Southeastern United States. The fertilizer treatments included a non-fertilized control, urea, and three different enhanced efficiency N fertilizers. Two years after fertilization, soil from the upper 15 cm in each of five treatments from four different locations was collected. A greenhouse study was established to examine the availability of the residual fertilizer N in the soil. Two...

Dispersal of seeds by scatter-hoarding rodents is common among tropical and temperate tree species, including chestnuts in the genus Castanea. Backcrossed (BC) interspecific hybrid chestnuts exhibit wide variation in seed traits: as the parent species (Castanea dentata and C. mollissima) have distinct seed phenotypes and tend to be handled differently by seed dispersers, phenotypic variation in BC trees is likely due to inheritance of genes that have undergone divergent evolution in the parent species. To identify candidate genomic regions for interspecific differences in seed dispersal,...