Treesearch

Current design standards incorporate the use of preservative treated and naturally durable wood where conditions are suitable for deterioration, but treatment options for mass timber products, particularly, cross laminated timber (CLT) remain to be addressed. Termiticide treatment is a necessity for CLT structures, especially in southeastern climates. Wood species currently used to fabricate CLT are non-durable, and current design standards do not properly address incorporation of preservative treatments into these systems. In this study, 12” x 14” x 4” Douglas-fir CLT pieces were installed...

Field data examining the long-term effects of chemical wood preservatives on refractory wood species with abundant heartwood is limited. This study was initiated to determine, by ground contact exposure, the effectiveness of preservativetreated heartwood material comprised of refractory Douglas-fir, Engelmann spruce, or southern pine. The study compared incised and non-incised lumber treated at three retentions with either ammoniacal copper arsenate (ACA) or chromated copper arsenate (CCA) and placed in ground contact at Mississippi and Wisconsin field test sites in 1975 and 1976, respectiv...

Cross laminated timber (CLT) is a relatively recent addition to the North American timber construction market. CLT has been successfully used for construction in Europe and, in the past few years, manufacturers have looked forward to expanding the use of this product into the North American market. However, no termite susceptibility experiments have been published for the product and no standards exist for testing of the CLT and other mass timber products against termites. It is extremely important to evaluate the resistance to degradation of CLT, especially if the manufacturers are trying...

In the US, codified seismic design procedure requires the use of seismic performance factors which are currently not available for CLT shear wall systems. The study presented herein focuses on the determination of seismic design factors for CLT shear walls in platform type construction using the FEMA P-695 process. Results from the study will be proposed for implementation in the seismic design codes in the US. The project approach is outlined and selected results of full-scale shear wall testing are presented and discussed. Archetype development, which is required as part of the FEMA...

DNA barcoding has been proposed as a useful tool for forensic wood identification and development of a reliable DNA reference library is an essential first step. Xylaria (wood collections) are potentially enormous data repositories if DNA information could be extracted from wood specimens. In this study, 31 xylarium wood specimens and 8 leaf specimens of six important commercial species of Pterocarpus were selected to investigate the reliability of DNA barcodes for authentication at the species level and to determine the feasibility of building wood DNA barcode reference libraries from...

Understanding why wood bonds fail is an excellent route toward understanding how to make them better. Certifying a bonded product usually requires achieving a specifc load, percent wood failure, and an ability to withstand some form of moisture exposure without excessive delamination. While these tests protect the public from catastrophic failures, they are not very helpful in understanding why bonds fail. Understanding failure often requires going beyond what meets the naked eye, conducting additional tests, probing the wood surface, the fracture surface, adhesive properties, and the...

PREMISE OF THE STUDY: Various nondestructive testing technologies have been used for detecting and visualizing internal defects in urban trees. The results obtained by using diferent nondestructive testing tools can be interpreted in diferent ways, which may result in inaccurate assessment of the true condition of the inspected trees. The main objective of this study was to evaluate the reliability of acoustic tomography and ground-penetrating radar (GPR) technology for detecting internal decay in a number of diferent tree species. METHODS: One hundred and forty-seven individual trees of...

Continuous exterior insulation is becoming more common in North American above -grade walls in both retrofit applications and new construction, as a means to improve the thermal performance of wall assemblies. Although moisture performance of wood-frame wall assemblies has been studied extensively, the drying capability of wall assemblies with exterior insulation and an interior vapor retarder in cold climates is not well characterized. This study monitored the hygrothermal performance of wall assemblies with and without exterior insulation under high and low interior humidity conditions...

Near-infrared spectroscopy (NIRS) is a potential, feld-portable wood identifcation tool. NIRS has been studied as tool to identify some woods but has not been tested for Dalbergia. This study explored the efcacy of hand-held NIRS technology to discriminate, using multivariate analysis, the spectra of some high-value Dalbergia wood species: D. decipularis, D. sissoo, D. stevensonii, D. latifolia, D. retusa, all of which are listed in CITES Appendix II, and D. nigra, which is listed in CITES Appendix I. Identifcation models developed using partial least squares discriminant analysis (PLS-DA)...