Treesearch

The objective of this study was to investigate the effects of tree diameter and juvenile wood on acoustic wave propagation in standing trees. Two-layer tree models with various diameters and proportions of juvenile wood were constructed to examine the effects of these two factors on propagation patterns and velocity of acoustic waves. The simulation results and analysis indicated that acoustic wave propagation in trees is dependent on both tree diameter and propagation distance. In the context of time-of-flight (TOF) acoustic measurement on standing trees with a test span of 1.2 m, when...

A desire to develop biorenewable materials has led to lactide caprolactone copolymers being used in adhesive, medical, and pharmaceutical products. Use of this alternative material may diminish human impact on the environment and create products that are biocompatible. One advantage of these materials compared with other typical petroleum-based polymers is that they are easily degraded by microorganisms. In this study, the biodegradation of representative lactide caprolactone macromonomers and an acrylic pressure sensitive adhesive incorporating these macromonomers was followed by a...

Tyloses are extruded cell contents of adjoining parenchyma cells that result in the obstruction of vessels. The function of tyloses in live trees is uncertain, but it has been proposed that they increase the natural durability of the wood by limiting water movement and the probing of fungal hyphae. Chestnut oak (Quercus montana, aka Quercus prinus) is inconsistent in producing tyloses; an initial study indicated a wide variation in the frequency of tyloses within and between trees of chestnut oak from three different states: VA, TN, and PA. This naturally occurring variation in tylosis...

Morphology analysis of cellulose nanocrystals (CNCs) using transmission electron microscopy (TEM) and atomic force microscopy (AFM) images is an important step in the design and optimization of the processes employed in the manufacture and utilization of CNCs. Current protocols used in the analyses of CNC particle morphology for such microscopy images are largely manual and time-consuming, and often produce inconsistent results between different researchers. This paper describes a new semi-automated image analysis framework that can reliably and quickly detect and classify CNCs from TEM...

January housing data showed the second consecutive month of total starts greater than 1.5 million units. However, total, single- and multifamily starts decreased month-over-month and year-over year. Aggregate (month-over-month and year-over-year) U.S. housing market data were mixed. New and existing house sales were positive month-over-month and year-over-year. Residential construction spending was positive month-over-month. On a year-over-year basis, total and single-family expenditures improved 21% and 24%, respectively.

Anoplophora chinensis (Forster) is an invasive species that can damage many tree species in orchard, urban, and forested habitats. Adult survival, reproduction, and egg hatch of A. chinensis from Italy and China are evaluated at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40 ºC) under laboratory conditions. The estimated Tmax for longevity was 42 and 33 ºC for females and 42 and 39 ºC for males from China and Italy, respectively. The estimated Tmax, Tmin, and optimum temperature for fecundity were 35, 9, and 29 ºC, respectively. Females laid eggs at 15–30 ºC and eggs...

There is mounting scientific evidence that greenness is associated with improved cardiovascular health. However, few studies have distinguished between vegetation type, measured perceived green space access, or investigated heterogeneity of associations across categories of neighborhood sociodemographic and racial/ethnic composition. We conducted an ecologic spatial analysis of associations of three objective measures of greenness (percent vegetation cover, percent tree canopy cover, and greenness density), and one measure of perceived access to green spaces with census tract level...

Ownership of forestland in the United States has changed in recent decades, including the proliferation of timber investment management organizations (TIMOs) and real estate investment trusts (REITs), with the potential to alter forest management and timber supply. This article quantifies forest ownership transitions among ownership categories between 2007 and 2017 and investigates how and why large corporate ownerships own and manage their forestlands. Ownership transitions were determined from refined USDA Forest Service, Forest Inventory and Analysis data; we also conducted a survey of...

Sheet molding compounds (SMC) are commonly used in automotive applications as they lead to increased fuel efficiency of vehicles due to their high strength to weight ratios. This study focuses on understanding the effect of replacing calcium carbonate (CaCO3) with hollow glass spheres (HGS) in an unsaturated polyester resin matrix SMC composite with the ultimate goal to further reduce density without compromising performance. The resulting glass fiber (GF)-reinforced syntactic foam laminate composites with GF content ranging from 10 to 15 vol% have densities of 1.2 and 1 g/cm3 , respectivel...

Waterborne acrylic coatings contain volatile and non-volatile coalescents. Volatile organic compound (VOC) coalescents enable film formation of hard acrylic polymers at ambient temperature, but their evaporation results in air pollution and health concerns. Non-volatile alternatives are available, but they remain in the coating long-term and as a result films are often tacky and lack adequate hardness. Reinforcing mineral fillers are available, but are associated with sustainability challenges inherent to mineral mining. An alternative approach demonstrated here utilizes a renewably-sourced...