Treesearch

Since biodiversity often increases ecosystem functioning, changes in tree species diversity could substantially influence terrestrial carbon cycling. Yet much less is known about the relationships between forest structural diversity (i.e., the number and physical arrangement of vegetation elements in a forest) and carbon cycling, and the factors that mediate these relationships. We capitalize on spaceborne lidar data from NASA's Global Ecosystem Dynamics Investigation (GEDI) and on-the-ground forest inventory and analysis (FIA) data from 1796 plots across the contiguous United States to...

The present study compared seasonal changes in the concentrations of calcium oxalate (CaOx) crystals and total calcium (Ca) in the foliage of red spruce (Picea rubens Sarg.), white pine (Pinus strobus L.), black oak (Quercus velutina L.), and sugar maple (Acer saccharum Marshall) trees. Samples were collected from the same four replicate trees of each species starting in June 2014 through September 2015 for a total of six times for conifers and four times for hardwoods. Calcium oxalate was extracted from tissues using a method developed in our laboratory in 2015. The purity of the extracted...

Alaska yellow-cedar (Cupressus nootkatensis) is a softwood tree species native to the Pacific coast of Canada and is known to contain various biologically active extractive components. Extractives are nonstructural chemical compounds found within wood that are primarily responsible for the durability of the tree itself and can, in some species, fend off attacks from microbes, insects, and other agents. Durability in wood often translates to biological activity in the human body, and some extractive compounds have already been identified as being biologically active. Extractives of Alaska...

Many durable wood species contain extractives with biologically active chemical components that have potential to be used for the development of pharmaceuticals. For this study, extractive compounds from western redcedar (Thuja plicata) were separated by their relative polarities using liquid–liquid fractionation and characterized through gas chromatography–mass spectroscopy (GC–MS). Fractionation was successful at separating the components of western redcedar in a consistent manner, and GC–MS was able to identify the presence of various terpenoid compounds, primarily nezukone and thujaplic...

Commonly the raw material round timber is reduced into smaller parts such as solid wood boards, sheets of veneer, strands, particles, and fibers for further manufacturing and processing. In following steps, the single wooden pieces are joined together by adhesive bonding to achieve the final structures such as various types of wood laminations or wood-based panels. This chapter describes the various mechanical connecting and adhesive bonding solutions. Different mechanical connector systems are introduced in theory and practice. A major part of the chapter is dedicated to wood adhesion and...

Glue laminated timber (glulam) is an engineered wood product composed of wood laminations bonded together with durable adhesives. Glulam is versatile ranging from simple, straight beams to complex, curved structural members and are used in a variety of applications including residential and commercial construction where they are often exposed due to the timeless aesthetic of wood. Glulam beams are also resource-efficient and offer designers highly predictable structural and fire performance when used in accordance with design specifications. However, factory-cut or field modifications to...

Timber structures decay over time with degradation in their structural integrity. Changing environmental conditions, varying loads, exposure to moisture or insect attacks lead to changes in their vibrational response behaviour. Here we present a low-cost device used as a triggered exciter to enable the monitoring of the structural integrity of timber bearers or even power poles in electricity networks. The actuation is initiated by a novel purpose-built, calibrated spring-loaded piezo-electric exciter. The device is connected to a fibre-optical network with optical accelerometers to...

Sulfurized polyacrylonitrile (SPAN) is a promising cathode active material capable of suppressing lithium polysulfide dissolution in lithium−sulfur (Li−S) batteries. However, due to the low S content in SPAN, achieving a high SPAN areal loading without compromising specific capacity and cycling stability would be required. To address this challenge, we took advantage of the inherent porous structure of natural wood and engineered carbonized delignifed wood (CDW) frameworks using a delignification/low-temperature pyrolysis approach. The unique design of the SPAN-impregnated CDW (SPAN@CDW)...

As populations in developing areas continue to increase in recent years, urban and community forestry (U&CF) has received considerable attention due to the ecological, social, and economic significance of trees and green landscapes in urban and semi-urban settings. Based on a regional survey of private, public, and nonprofit businesses and agencies involved in U&CF, we first developed a complete profile of the U&CF sector in the southern United States (SUS) and then estimated the economic contribution of U&CF businesses and activities to the thirteen-state regional economy. We estimated...

Candidate insecticide products under consideration for use as soil termiticides are required to have specific efficacy data for federal registration by the U.S. Environmental Protection Agency (EPA). Data that are collected annually by the U.S. Department of Agriculture (USDA) Forest Service (FS) Forest Products Laboratory (FPL), Durability and Wood Protection research work unit (RWU 4723), serve to fulfill this need. The FS group installs and evaluates wooden test pieces on plots of soil treated with candidate termiticide products. Data from these studies are used in the registration...