Treesearch

This report provides a summary of technical papers presented in Session #90 of the recent IUFRO XXII World Forestry Congress held in Brisbane, Queensland, Australia, August 8–13, 2005. Papers in this report include the oral presentations, poster presentations, and panel discussions exploring and providing technical information on the potential adaptability and applicability of using wood–composites technologies to create value-added commodities and new innovative biobased composite products. These presentations reviewed how wood- and bio-fiber-composite technologies allow users to add...

The increasing number of western juniper trees per acre and the expansion of its range is resulting in watershed degradation, loss of site productivity, decrease in forage production, loss of wildlife habitat, and overall reduction in biodiversity. Previous studies and anecdotal evidence indicate western juniper has fairly good resistance to decay and insect attack, and it might be suitable for decking and siding applications as well as for particleboard furnish. We evaluated the performance of smooth- planed and saw-textured western juniper lumber and particleboard finished with a variety...

The mechanism by which hydroxymethylated resorcinol (HMR) primer improves the durability of various adhesives to wood has been hypothesized as covalent chemical links between the adhesive and primer and possibly between the primer and wood. The present work presents experiments to test this hypothesis. In the first test, some resorcinol was displaced by 2- methylres-orcinol at various levels to decrease crosslinking but retain hydroxymethyl groups on the active primer for reaction with adhesive and possibly with wood. Increased substitution for resorcinol produced lower durability, which...

Nondestructive testing (NDT) of wood products, such as lumber and veneer, for stiffness and strength evaluation has been proven and commercialized for many years. The NDT concept has been extended and commercialized in the Director HM-200™ tool for testing logs in advance of processing so manufacturers can make more informed log purchases and better match logs to customer needs for product stiffness and strength. Further extension of the NDT concept to standing timber is a logical progression and a new commercial tool, the Director ST-300™, has just been developed for this application....

Wood fibers can be used to produce a wide variety of low-density three-dimensional webs, mats, and fiber-molded products. Short wood fibers blended with long fibers can be formed into flexible fiber mats, which can be made by physical entanglement, nonwoven needling, or thermoplastic fiber melt matrix technologies. The most common types of flexible mats are carded, air-laid, needlepunched, and thermobonded mats. In carding, the fibers are combed, mixed, and physically entangled into a felted mat. These are usually of high density but can be made at almost any density. Air-laid webs are...

Excess nutrients, including phosphorus, can cause eutrophication in surface water and reservoirs. We tested the phosphate removal capacity of juniper fiber through isotherm, kinetic, column, and field tests. Heavy metals from an acid mine drainage (AMD) site were precipitated on the surface ofjuniper fiber. The modified fiber was tested in laboratory- caled batch and column tests. Elemental analysis showed that soluble iron species deposited on the modified fiber acted as an inorganic adsorbent for anions; sorption capacity of this juniper fiber was higher than that of other conventional...

This chapter presents a theoretical model to explain the relationship between the mechanical properties and the chemical components of wood. This model is then used to describe the effects of altered composition on those mechanical properties. Many of the theories presented are only partially proven and just beginning to be understood. These theories should be considered as a starting point for dialogue between chemists and engineers that will eventually lead to a better understanding of the chemistry of wood strength.

A new genus and species of Euphorbiaceae s.s., Brasiliocroton mamoninha, is described from two disjunct areas of lowland forest remnants in eastern and northeastern Brazil. It is a member of tribe Crotoneae and was previously confused with Croton and Micrandra. The resemblance to Micrandra is based on the branched inflorescences and terminal position of the pistillate flowers, trigonous capsules, and ovate leaves with basal glands, but the stamens are more numerous and the pollen is inaperturate (like Croton). Brasiliocroton has a stellate-rosulate indumentum like some Croton species, but...

Conifer resin and phloem tissue contain several phytochemical groups, composed primarily of monoterpenes, diterpene acids, and stilbene phenolics. The effects of monoterpenes and phenolics on stem-colonizing bark beetles and their associated microorganisms have been studied to some extent, but the roles of diterpene acids are largely unknown. Diterpene acids are known to have substantial feeding deterrent and growth inhibiting effects on a variety of insect groups and are known to inhibit a variety of fungi. We tested three diterpene acids present in red pine, Pinus resinosa, at various...

An appreciation of rheology, material science, organic chemistry, polymer science, and mechanics leads to better understanding of the factors controlling the performance of the bonded assemblies. Given the complexity of wood as a substrate, it is hard to understand why some wood adhesives work better than other wood adhesives, especially when under the more severe durability tests. In general, wood is easy to bond to compared to most substrates, but it is harder to make a truly durable wood bond. A main trend in the wood industry is increased bonding of wood products as a result of the use...