Treesearch

This report summarizes information on condition assessment of in-service wood, including visual inspection of wood and timbers, use of ultrasound and probing/boring techniques for inspection, and assessment of wood and timbers that have been exposed to fire. The report also includes information on assigning allowable design values for in-service wood.

Spatial and temporal environmental heterogeneity is known to play an important role in the dynamics of populations and communities. However, the implications of this heterogeneity for developing and testing regional- to global-scale forest dynamics models are largely unexplored. Predictions from forest dynamics models are typically compared to chronosequences assembled from forest inventory data using the space-for-time substitution approach, which assumes that different-aged stands across space have followed (and will follow) the same dynamics. Often, this assumption is invalid in the...

Current forests no longer resemble historical open forest ecosystems in the eastern United States. In the absence of representative forest ecosystems under a continuous surface fire regime at a large scale, reconstruction of historical landscapes can provide a reference for restoration efforts. For initial expert-assigned vegetation phases ranging from prairie to forest across the Missouri Ozarks landscape, we reconstructed historical (1815 to 1850) forest densities, basal area, percent stocking or growing space, and canopy cover. After examination of structural means and ranges by initial...

Question: Human-altered disturbance regimes and agricultural land uses are broadly associated with reduced plant species diversity in terrestrial ecosystems. In this study, we seek to understand how fire frequency and agricultural land-use history influence savanna understorey plant diversity through complex relationships (i.e. indirect effects) among multiple biophysical variables. Location: Fort Bragg, NC, US, Savannah River Site, SC, US and Fort Stewart, GA, US. Methods: We use structural equation modelling (SEM) to evaluate the relationships among six groups of predictor variables and...

Longleaf pine ecosystems are a distinct part of the forest landscape in the southeastern USA. These biologically diverse ecosystems, the native habitat of numerous federally listed species, once dominated more than 36.4 million ha but now occupy only 1.4 million ha of forested land in the region. The Escambia Experimental Forest was established in 1947 through a 99-year lease with the T.R. Miller Mill Company of Brewton, AL, to explore all aspects of longleaf pine management. The 1,214-ha tract in southwest Alabama constitutes a unique example of longleaf pine ecosystems in all stages of...

In 1934, the Crossett Experimental Forest (CEF) opened to develop good forestry practices for the poorly stocked pine-hardwood stands that arose following the high-grading of the virgin forest. One CEF demonstration area has had no active silviculture other than fire protection since 1937; this 32.4-ha stand is now the Russell R. Reynolds Research Natural Area (Reynolds RNA). Periodic inventories of this tract provide a unique account of long-term stand development under minimal anthropogenic disturbance. For instance, successional change has been characterized by the slow conversion from...

The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a comprehensive population genetic study of 209 G. morbida isolates collected from Juglans and Pterocarya from 17 geographic regions distributed across 12 U.S. states. The study was based on sequence...

Given the low intraspecific chloroplast diversity detected in northern red oak (Quercus rubra L.), more powerful genetic tools are necessary to accurately characterize Q. rubra chloroplast diversity and structure. We report the sequencing, assembly, and annotation of the chloroplast genome of northern red oak via pyrosequencing and a combination of de novo and reference-guided assembly (RGA). Chloroplast DNA from 16 individuals was separated into four MID-tagged pools for a Genome Sequencer 20 quarter-run (Roche Life Sciences, Indianapolis, IN, USA). A four-step assembly method was used to...

Persian walnut (Juglans regia L) is an economically important species cultivated worldwide for its wood and nuts. Despite the increasing interest in the development of conservation strategies for walnut germplasm, an accurate and full-scale overview of wild genetic resources of J. regia has not been conducted because natural populations are located in regions of Asia historically difficult to access. In this study, we estimated the genetic diversity and spatial genetic structure of 39 autochthonous Persian walnut populations sampled across its Asian range using 14 neutral microsatellite...

Background and aims As low initial uptake and essentially zero later uptake limit efficacy ofN fertilization for temperate conifers, we investigated factors limiting long-term tree uptake of residual 15N-labeled fertilizer. Methods We used a pot bioassay to assess availability of 15N from soil sampled 10 years after fertilization of a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand with 15N-urea (200 kg N ha−1). Douglas-fir seedlings were grown for 2 years in organic (designated LFH) and mineral soil (0–10 cm) layers reconstructed from control and fertilized plots; residual...