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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
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Title: Shading Aboveground L-joint and Lap-joint tests: Comparison of White Pine and Sugar Maple Test Assemblies

Source: Forest Products Journal, Volume 61, Number 3, 265-269. 2011

Author(s)Clausen, Carol A.; Linder, Daniel L.

Publication Year: 2011  View PDF »

Category: Journal Articles
Associated Research Project(s):   FPL-4723-3

Abstract: Five-year performance ratings are presented for two types of untreated, uncoated wood joints (L and lap) in aboveground tests under shaded conditions. The effect of shading on moisture entrapment in pine and maple L and lap joints was evaluated in a moderate decay zone (Madison, Wisconsin). Variations were observed between wood species, visual ratings, joint type, moisture content readings, and fungal growth on the specimens. Representative fungal fruiting bodies were identified as members of the Peniophorella praetermissa species complex by microscopic and DNA analyses. After 5 years, the highest average rating (indicative of most severe deterioration) occurred in white pine L-joint specimens followed by maple lap joints and maple L joints. Pine and maple L-joint specimens demonstrated considerably lower rating variation between specimens compared with lap-joint specimens. White pine lap joints shaded with a tarp had lower average moisture content but showed similar average ratings to pine lap joints shaded by a tree. Regardless of the shading method. white pine lap joints had the lowest average decay rating. Under shaded conditions in a moderate decay zone, untreated and uncoated L-joint performance was notably more uniform from specimen to specimen than lap-joint performance following 5 years of outdoor exposure. A single-point moisture content taken at the time of inspection was not a reliable indicator of the degree or rate of decay for aboveground joint test assemblies evaluated in this study. Likewise, uniform specimen wetting or drying is not predictable under shaded conditions.

Keywords: Timber joints, joints, testing, deterioration, wood-decaying fungi, biodegradation, fasteners, moisture, wood moisture, Acer saccharum, Pinus strobus, shades, shadows, weathering, durability, species differences, Peniophorella praetermissa, resistance to decay, decay fungi, sugar maple, white pine, lap joints, L-joints, connectors, maple, pine, moisture content, exposure tests, timber connectors

Publication Review Process: Formally Refereed

File size: 251 kb(s)

Date posted: 10/17/2011

This publication is also viewable on Treesearch:  view
RITS Product ID: 41244
Current FPL Scientist associated with this product
Clausen, Carol A.
Supervisory Research Microbiologist

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