Treesearch

Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings. Filter-based absorption measurements were corrected and compared to photoacoustic absorption results. BC absorption was segregated from the total light extinction to estimate the BrC absorption from individual sources. Results...

Manufacturing building products such as wood panels has environmental impacts, including contributions to climate change. This paper is a compilation of four studies quantifying these impacts using the life-cycle assessment (LCA) method on five wood-based panel products made in North America during 2012. LCA is an internationally accepted and standardized method for evaluating the environmental impacts of products. Using LCA, holistic environmental impacts were calculated based on survey data from mills on emissions to air and water, solid waste, energy consumption, and resource use. The...

The scope of this research was to evaluate the influence of xylem ray (XR) and degree of polymerization (DP) of holocellulose in Oriental beech wood (Fagus orientalis Lipsky.) on impact bending strength against two white-rot fungi. Beech wood specimens, exposed to Pleurotus ostreatus and Trametes versicolor, were evaluated for impact bending strength at 15-day intervals for 120 days. Microscopic evaluations at each time interval indicated that both fungi degraded marginal ray parenchyma at early stages of decomposition causing a drastic loss in impact bending strength. However, the two...

This paper describes the current state of the United States economy and provides general and statistical information on forest products markets in terms of production, trade, consumption, and prices. Market developments are described for sawn softwood, sawn hardwood, softwood log trade, wood-based panels, paper and paperboard, fuelwood, forest product prices, and housing starts. Policy initiatives that can affect domestic markets and international trade in wood products are also discussed in some detail. Data are provided through the end of the year 2013 with estimates for 2014 and...

Documenting the environmental performance of building products is becoming increasingly common. Creating environmental product declarations (EPDs) based on life-cycle assessment (LCA) data is one approach to provide scientific documentation of the products’ environmental performance. Many U.S. structural wood products have LCA-based “eco-labels” developed under the ISO standard 14025. In this study, the standard dictates underlying life-cycle inventory (LCI) data to be used reflect current practices in the industry. Therefore, gate-to-gate manufacturing LCI data for I-joist must be...

On average, new residential construction accounts for about one-third of all wood products consumed in the United States annually. During periods of robust housing activity, 45% or more of all wood products consumed are for new single-family and multifamily housing. This can fall to as low as 20% or less during times of economic recession. Unfortunately, 2012 was not an average year for new residential construction. The housing boom that occurred between 2000 and 2006 turned into a major housing recession in 2007. The recession bottomed out in 2009, with steady improvements being made...

Low-value residues from forest restoration activities in the western United States intended to mitigate effects from wildfire, climate change, and pests and disease need a sustainable market to improve the economic viability of treatment. Converting biomass into bioenergy is a potential solution. Life-cycle assessment (LCA) as a sustainable metric tool can assess the impact of new bioenergy systems. Using the internationally accepted LCA method, this study evaluated the syngas electricity produced via a distributed-scale biomass pyrolysis system called the Tucker Renewable Natural Gas...

Conifers possess a suite of physiochemical defenses that protect their subcortical tissues from bark beetle -fungal complexes. These defenses include rapid induction of terpenoids and phenolics at the site of attack. Studies of the distribution, induction, and bioactivity of conifer terpenoids have focused heavily on monoterpenes. We assessed induction of diterpene acids in white spruce (Picea glauca) and red pine (Pinus resinosa) to fungal associates of two bark beetles, and the responses of four spruce beetle (Dendroctonus rufipennis)—associated fungi to three diterpene acids. Constitutiv...

Electrical impedance spectra of wood taken at macroscopic scales below the fibre saturation point have led to inferences that the mechanism of charge conduction involves a percolation phenomenon. The pathways responsible for charge conduction would necessarily be influenced by wood structure at a variety of sub-macroscopic scales – at a mesoscale – but these questions have not yet been addressed. The goal of this work is to explore if mesoscale anatomical features in wood affect impedance spectra. Small (0.5mmdiameter) needles were used as electrodes and were configured such that the line...

Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB) structural panel sheathing were measured over a period from mid-November 2011 through March 2013 in both north- and south-facing orientations in test structures near Washington, DC, USA. Wall configurations varied in exterior...