Treesearch

A small-plot field trial was conducted to examine the area of influence of fipronil at incremental distances away from treated plots on the Harrison Experimental Forest near Saucier, MS. Small treated (water and fipronil) plots were surrounded by untreated wooden boards in an eight-point radial pattern, and examined for evidence of termite feeding every 60 d for 1 yr after treatment. Circular areas of 0, 0.28, 1.13, 2.55, 4.52, 7.07, and 10.18 m-squared around the treated plots were installed to evaluate feeding damage by termites on the boards. The relationship between feeding damage to...

The U.S. Department of Agriculture (USDA), Forest Service, State and Private Forestry (S&PF) began reporting tree planting in the United States in 1952 in an annual report, Tree Planting in the United States. In 2000, the report was discontinued amid growing concern over the manner in which much of the tree planting data were collected.

After fire exposure, design professionals are sometimes called upon to determine if the charred heavy timbers (Figure 1) are safe for future use without additional support or repairs. In this article, the authors present a sequence of reasoned steps that will help design professionals analyze charred timbers and gain the type of information needed to decide whether the charred timbers are adequate based on the applicable building code.

Sliding friction between cellulose Iß nanocrystals is studied using molecular dynamics simulation. The effects of sliding velocity, normal load, and relative angle between sliding surface are predicted, and the results analyzed in terms of the number of hydrogen bonds within and between the cellulose chains. We find that although the observed friction trends can be correlated with hydrogen bonding, it may not be the most significant factor in determining frictional behavior on cellulose nanocrystal surfaces.

Ethanol in sapwood was analyzed along vertical transects, through small spot cankers and larger basal cankers, of Phytophthora ramorum-infected stems of Quercus agrifolia at three sites in California. Trees with large basal cankers, known to attract scolytid beetles, had a 4.3 times higher ethanol level than trees with spot cankers that attract fewer beetles. We conclude that ethanol in P. ramorum cankers functions as a primary host attractant for scolytid beetles and is an important link in colonization of these cankers and accelerated mortality of Q. agrifolia. The results of this...

Organisms that adopt phenotypically plastic anti-predator strategies during larval stages may incur fitness costs later in development. These costs are typically difficult to define in many species. The difficulty identifying ecological trade-offs may result from experimental comparisons that do not adequately mirror naturally occurring predator-prey relationships. To examine this, we captured 61 newly metamorphosed Acris blanchardi from ponds dominated either by fish or invertebrate predators. These predators are known to induce alternate phenotypic anti-predator responses at the larval...

White-nose syndrome recently emerged as a disease affecting bats that hibernate in caves and abandoned mines during winter. This disease is caused by the fungus Pseudogymnoascus destructans, and has caused the death of millions of bats in the Eastern United States and Canada. This fungus grows in relatively cold conditions with high humidity, which makes many caves, abandoned mines, and other underground structures optimal growing sites for the disease during winter. A number of treatments for combating white-nose syndrome have been tested, but practical and effective treatments for the...

Wind-driven rain provides the primary external moisture load for exterior walls.Water absorption by the cladding, runoff, and penetration through the cladding or at details determine how a wall system performs. In this paper we describe a new laboratory facility that can create controlled outdoor and indoor conditions and use it to investigate the water management performance of a typical exterior wall assembly. Specifically we have quantified how much water gets past the cladding and hits the water-resistive barrier under particular conditions for a common lap siding.

In spite of the significant potential of cellulose nanocrystals as functional nanoparticles for numerous applications, a fundamental understanding of the mechanical properties of defect-free, crystalline cellulose is still lacking. In this paper, the elasticity matrix for cellulose Iß with hydrogen bonding network A was calculated using ab initio density functional theory with a semi-empirical correction for van der Waals interactions. The computed Young’s modulus is found to be 206 GPa along [001] (c-axis), 98 GPa along [010] (b-axis), and 19 GPa along [100] (a-axis). Full compliance...

The movement of chemicals through wood is necessary for decay and fastener corrosion to occur in forest products. However, the mechanism responsible for the onset of fastener corrosion and decay in wood is not known. The onset occurs before the formation of free water in wood cavities and aqueous chemical transport would be possible. Here, we propose that the onset mechanism is the hemicelluloses going through a moisture induced glass transition. As nm-scale regions of mechanically softened hemicelluloses in cell walls percolate, pathways for chemical transport are created. The ability of...