Banner for LabNotes
From Lab Notes
Contact Information
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592


You are here: FPL Home  / Information Products & Services  / Publications

Requested Product

Title: The role of moisture content in above-ground leaching

Source: IRG/WP ; 07-50245. Stockholm, Sweden : IRG Secretariat, 2007. 15 pages.

Author(s)Lebow, Stan; Lebow, Patricia

Publication Year: 2007  View PDF »

Category: Journal Articles

Abstract: This paper reviews previous reports on the moisture content of wood exposed above ground and compares those values to moisture contents obtained using simulated rainfall and immersion methods. Laboratory leaching trials with CCA-treated specimens were also conducted and the results compared to published values for leaching of CCA-treated specimens exposed above ground outdoors. Previous researchers have reported that the moisture content of wood exposed above ground may range from over 80% to minimums of approximately 10%. In most studies, the maximum moisture content fell within 40% to 55% for horizontal specimens and between 30% to 50% for vertical specimens. Minimum moisture contents were generally in the 10% to 15% range. Average moisture contents reported for horizontal exposures ranged from 21% to 26%, while the averages reported for vertical exposure were 19% and 25%. The simulated rainfall method produced a maximum moisture content of 49% in CCA-treated lumber specimens, but did not provide realistic drying between rainfall events. A 14-day continuous immersion with lumber specimens yielded an average final moisture content of 52% in CCA-treated specimens. Both methods produced cumulative copper and chromium leaching values slightly below, and arsenic values slightly above, those reported for wood exposed outdoors. Trials with smaller specimens indicated that immersion and drying schedules could be adapted to create moisture contents similar to those reported in service. Leaching methods could be improved by developing a better understanding of moisture conditions in wood exposed above ground, and of the role of drying cycles in preservative leaching.

Keywords: Above ground, moisture content, leaching, simulated rainfall, immersion, rain, rainfall, wood preservatives, wood moisture, chromium, copper, arsenic, simulation methods, weathering, preservatives, chromated copper arsenate, moisture content, CCA

File size: 161 kb(s)

This publication is also viewable on Treesearch:  view
RITS Product ID: 28565
Current FPL Scientists associated with this product (listed alphabetically)
Lebow, Patricia K.
Mathematical Statistician
Lebow, Stan T.
Research Forest Products Technologist

Additional items that might interest you
View the video celebrating FPL's 100 years of public service in 2010, from the producers of the Greatest Good....view

Research Highlights from FPL....view

Termite Eradication: A search for the Holy Grail.... view

Moisture Management in Residential Construction Series videos...view

Wood Floor Systems in Residential Construction Series videos....view
- FPL's Mission and Strategic Plan -

FPL's mission is to identify and conduct innovative wood and fiber utilization research that contributes to conservation and productivity of the forest resource, thereby sustaining forests, the economy, and quality of life. ... ..more »

- FPL Research Emphasis Areas -
Advanced Composites

As an integral part of the FPL mission, we improve the long-term sustainability of our Nation's forests by creating valuable composite products from biobased materials ... ..more »

Advanced Structures

The FPL has been in the forefront of wood-frame housing research since 1910 and has long been recognized as a world leader in such housing-related areas as engineered wood ... ..more »

Forest Biorefinery

We all know the compelling reasons that the United States needs to reduce its dependence on fossil fuels. Historically, the greatest increases in energy demand have been for transportation fuels ... ..more »


A leader in wood products research for over a century, the FPL is positioning itself to become the lead Federal research facility for the application of nanotechnology in forest products ... more »

Woody Biomass Utilization

Forests in the United States contain a substantial amount of small-diameter, overstocked, and underutilized material.FPL research projects are exploring the potential of the small-diameter ... ..more »