Treesearch

Most of the arborescent Croton species in the New World were treated by Webster as belonging either to C. sect. Cyclostigma Griseb. or C. sect. Luntia (Neck. ex Raf.) G.L. Webster. The circumscription of C. sect. Cyclostigma has been treated recently. In this paper we focus on C. sect. Luntia, which was subdivided by Webster into two subsections, C. subsect. Matourenses and subsect. Cuneati. Using chloroplast trnL-F and nuclear ITS DNA sequence data, morphology and a broader sampling of additional Croton lineages, we found that the two subsections are not closely related and form distinct...

Because of the potential risk associated with moving emerald ash borer (EAB)-infested firewood, the interstate movement of all hardwood firewood in the USA is currently restricted under the Federal quarantine. Communities and firewood producers are now faced with decisions on how to treat their firewood for interstate commerce. The new US Federal regulations for heat sterilization of ash firewood require holding a core temperature of 71ºC for 75 min, which is higher than current international standard for heat treating solid wood packaging materials (ISPM 15). A study funded by the US...

Under proper conditions, wood will give centuries of service. However, under conditions that permit the development of wood-degrading organisms, protection must be provided during processing, merchandising, and use. The organisms that can degrade wood are principally fungi, insects, bacteria, and marine borers.

Many commonly used wood species can deteriorate if exposed to conditions that support growth of wood-degrading organisms (see Chap. 14). Wood products can be protected from the attack of decay fungi, harmful insects, or marine borers by applying chemical preservatives. Preservative treatments greatly increase the life of wood structures, thus reducing replacement costs and allowing more efficient use of forest resources. The degree of protection achieved depends on the preservative used and the proper penetration and retention of the chemicals. Some preservatives are more effective than...

Environmental accumulation of preservative adjacent to a chromated copper arsenate (type C)–treated wetland boardwalk was evaluated. The site is considered a realistic ‘‘worst case’’ because of the large volume of treated wood, low current speeds, high annual rainfall, and environmental sensitivity. Soil and sediment samples were collected before construction and 0.5, 2, 5.5, 11, 24, 60, and 131 months (11 y) after construction and analyzed for total chromium, copper, and arsenic concentrations. This article updates the findings after 11 years of exposure. Environmental concentrations...

This chapter gives an overview of the general types and composition of wood-based composite products and the materials and processes used to manufacture them. It describes conventional wood-based composite panels and structural composite materials intended for general construction, interior use, or both. This chapter also describes wood–nonwood composites. Mechanical properties of these types of composites are presented and discussed in Chapter 12. Because wood-based composites come in a variety of forms, we briefly describe several of the most common commercial products. This chapter is...

Data generated from wood-product durability evaluations can be difficult to interpret. Standard methods used to evaluate the potential long-term durability of wood products often provide little guidance on interpretation of test results. Decisions on acceptable performance for standardization and code compliance are based on the judgment of reviewers or committees. This decision-making process has potential pitfalls, especially when there is pressure to minimize the time needed for evaluation. This paper discusses some of the pitfalls encountered in interpretation of in-ground and above-gro...

Effective mitigation of external fires on structures can be achieved flexibly, economically, and aesthetically by (1) preventing large-area ignition on structures by avoiding close proximity of burning vegetation; and (2) stopping flame travel from firebrands landing on combustible building objects. Using bench-scale and mid-scale fire tests to obtain flammability properties of common building constructions and landscaping plants, a model is being developed to use fast predictive methods suitable for changing environments imposed on a parcel lot consisting of structures and ornamental...

Fire safety is an important concern in all types of construction. The high level of national concern for fire safety is reflected in limitations and design requirements in building codes. These code requirements and related fire performance data are discussed in the context of fire safety design and evaluation in the initial section of this chapter. Because basic data on fire behavior of wood products are needed to evaluate fire safety for wood construction, the second major section of this chapter provides additional information on fire behavior and fire performance characteristics of...

In this study, the fire performance and decay resistance of solid wood and plywood treated with quaternary ammonia compounds (didecyl dimethyl ammonium chloride (DDAC) and didecyl dimethyl ammonium tetrafluoroborate (DBF)) were compared with the performance of untreated control specimens and specimens treated with common fire retardants ((monoammonium phosphate (MAP), diammonium phosphate (DAP) and ammonium sulphate (AS)). Test specimens were treated with 1% and 4% (% m/v) aqueous solutions of the chemicals. The fire performance tests were the fire tube test (ASTM E 69) which measures mass...