Treesearch

This article introduces an insulation system that takes advantage of the low thermal conductivity of still air and is made of wood and paper. The insulation, called the Mirrorpanel, is constructed as a panel of closely spaced layers of coated paper and held together in a frame of wood or fiberboard. Panels have been fabricated and tested at the laboratory scale, whole wall scale, and the building scale. A 1.2-m by 2-m by 0.185-m-thick wall section had an apparent thermal conductance of only 0.204 W m-2 K-1 including the structural wood frame, which is equivalent to a US R-value of 27.9 h...

In this paper, we demonstrate microwave flexible thin-film transistors (TFTs) on biodegradable substrates towards potential green portable devices. The combination of cellulose nanofibrillated fiber (CNF) substrate, which is a biobased and biodegradable platform, with transferrable single crystalline Si nanomembrane (Si NM), enables the realization of truly biodegradable, flexible, and high performance devices. Double-gate flexible Si NM TFTs built on a CNF substrate have shown an electron mobility of 160 cm2/V•s and ƒT and ƒmax of 4.9GHz and 10.6GHz, respectively. This demonstration...

Modulus of elasticity (MOE, or E) is one of the main quality indicators in structural lumber stress grading systems. Due to a relatively high amount of variability in contemporary sawn lumber, it is important that nondestructive evaluation technology be utilized to better discern high-E-value pieces from low-E-value pieces. The research described in this study is from a laboratory test of three nondestructive technologies applied to 343 pieces of visually graded No. 2 southern pine lumber collected across the southeast region of the United States. The evaluated technologies included...

The Third National Climate Assessment (NCA) process for the United States focused in part on developing a system of indicators to communicate key aspects of the physical climate, climate impacts, vulnerabilities, and preparedness to inform decisionmakers and the public. Initially, 13 active teams were formed to recommend indicators in a range of categories, including forest, agriculture, grassland, phenology, mitigation, and physical climate. This publication describes the work of the Forest Indicators Technical Team. We briefly describe the NCA indicator system effort, propose and explain...

Invader traits (including plant growth form) may play an important, and perhaps overlooked, role in determining macroscale patterns of biological invasions and therefore warrant greater consideration in future investigations aimed at understanding these patterns. To assess this need, we used empirical data from a national-level survey of forest in the contiguous 48 states of the USA to identify geographic hotspots of forest plant invasion for three distinct invasion characteristics: invasive species richness, trait richness (defined as the number of the five following plant growth forms...

Habitat invasibility is a central focus of invasion biology, with implications for basic ecological patterns and processes and for effective invasion management. ‘‘Invasibility’’ is, however, one of the most elusive metrics and misused terms in ecology. Empirical studies and meta-analyses of invasibility have produced inconsistent and even conflicting results. This lack of consistency, and subsequent difficulty in making broad cross-habitat comparisons, stem in part from (1) the indiscriminant use of a closely related, but fundamentally different concept, that of degree of invasion (DI) or...

This is the third in a series of periodic monitoring reports on LSOG or latesuccessional and old-growth (older) forest status trends on federally administered lands since implementation of the Northwest Forest Plan (NWFP or the Plan) in 1994. The objective of this monitoring is to determine if the NWFP is providing for conservation and management of older forests as anticipated. This report focused on the amount, distribution, and spatial arrangement of older forests across the NWFP landscape, and how these have changed as a result of disturbance and ingrowth starting with the year of the...

Simultaneous control over optical and thermal properties is particularly challenging and highly desired in fields like organic electronics. Here we incorporated cellulose nanocrystals (CNCs) into polyethylene oxide (PEO) in an attempt to preserve the iridescent CNC optical reflection given by their chiral nematic organisation, while reducing the composite thermal expansion. The hydrophilic nature and long-range self-organisation of CNCs facilitated structural control in the PEO matrix. The coefficient of thermal expansion (CTE) was determined by using contrast-enhanced microscopy digital...

Restoration of foundation species, such as the American chestnut (Castanea dentata) that was devastated by an introduced fungus, can restore ecosystem function. Understanding both the current distribution as well as biogeographic patterns is important for restoration planning. We used United States Department of Agriculture Forest Service Forest Inventory and Analysis data to quantify the current density and distribution of C. dentata. We then review the literature concerning biogeographic patterns in C. dentata. Currently, 431  30.2 million stems remain. The vast...

Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species-specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes...