Treesearch

There is rising global interest in growing more trees in order to meet growing population, climate change, and wood energy needs. Using recently published data on planted forests by country, we estimated relationships between per capita income and planted forest area that are useful for understanding prospective planted forest area futures through 2100 under various United Nations Intergovernmental Panel on Climate Change-inspired Shared Socio-economic Pathways (SSPs). Under all SSPs, projections indicate increasing global planted forest area trends for the next three to four decades and...

In an effort to avoid freeze-drying or solvent blending techniques and to better leverage the fact that preparation of cellulose nanocrystals (CNCs) result in aqueous dispersions, we investigated a water-assisted melt compounding approach to disperse cellulose nanocrystals in polypropylene (PP). A simple, water-based cetyltrimethylammonium bromide (CTAB) treatment of CNCs was used to reduce their hydrophilicity and inhibit hydrogen bonding. The aqueous suspension of treated CNCs was then blended with polypropylene in a thermokinetic mixer with various levels of a maleated polypropylene...

Cross-laminated timber (CLT) is a type of mass timber panel used in floor, wall, and roof assemblies. An important consideration in design and construction of timber buildings is moisture durability. This study characterized the hygrothermal performance of CLT panels with laboratory measurements at multiple scales, field measurements, and modeling. The CLT panels consisted of five layers, four with spruce-pine-fir lumber and one with Douglas-fir lumber. Laboratory characterization involved measurements on small specimens that included material from only one or two layers and large specimens...

The US housing construction market consumes vast amounts of resources, with most structural elements derived from wood, a renewable and sustainable resource. The same cannot be said for all nonresidential or high-rise buildings, which are primarily made of concrete and steel. As part of continuous environmental improvement processes, building life-cycle assessment (LCA) is a useful tool to compare the environmental footprint of building structures. This study is a comparative LCA of an 8360-m2, 12-story mixed-use apartment/office building designed for Portland, OR, and constructed from...

September housing data were tepid, with several monthly declines in starts, permits, completions, and new single-family sales. Total private residential construction spending was minimally positive; conversely, single-family construction expenditures declined slightly on a monthly basis. All housing start data were positive on year-over-year starts. Housing under construction remained positive, except for yearly multifamily data. Single-family housing completions were negative on a month-over-month and positive on a yearly basis. Existing sales continued their stagnant trend, monthly and...

October housing data were mostly negative, with several monthly declines in single-family starts, permits, and completions, and new single-family sales. Total private and single-family construction spending also were minimally negative. Total and single-family housing under construction remained positive, except for multifamily yearly data. Total and single-family housing completions declined on both month-over-month and yearly bases. New and existing sales continued their stagnant trend, monthly and yearly.

November housing data were mixed, with month-over-month increases and declines noted in single-family starts, completions, and spending. Total permits, total and single-family housing under construction, and expenditures remained positive. The new SF construction market needs consistent improvement to influence the housing construction market upward. Existing sales continued their stagnating trend, on both monthly and yearly bases.

Cellulose nanocrystal (CNC) suspensions were compounded into blends of poly(lactic acid) (PLA) and poly(vinyl acetate) (PVAc) using a novel wet compounding approach in which drying and compounding were carried out simultaneously. The resulting CNC/PLA composites were compared with those produced using a more traditional method of freeze-drying CNC suspensions followed by melt-blending into PLA. CNCs in wet compounded composites appeared to be well-dispersed in the PLA/PVAc blends, and films extruded from these compounds exhibited high transparency compared with melt-blended composites. Gel...

Magnetostrictive composite known as magnetostrictive nanocellulose membrances (MNMs) were fabricated by embedding Terfeonol-D particles into cellulose nanofibers (CNFs). MNMs inherit flexibility and biodegradability from CNF while exhibiting magnetomechanical responses; as such, the valuable rare-earth (Terfenol-D) particles can be recycled. Various orientations of the Terfenol-D particles were induced in the MNMs, and those with in-plane alignment showed the strongest magnetostrictive effect but the lowest Villari effect. Materials with such a unique combination of properties dovetail...

In January, total housing permits increased to their highest level in 13 years on a seasonally adjusted annualized basis. In December and January, total housing starts recorded their best two months since mid-2006, indicating a substantial year-over-year increase. However, total and single-family starts declined on a month-over-month basis. Total, single- and multifamily completions, and existing sales also decreased monthly. Single-family housing units under construction and single-family completions were negative on a year-over-year basis.