Effect of weathering on accuracy of fuel-moisture-indicator sticks in the Pacific Northwest.

Abstract

How much does weathering affect accuracy of fuel-moisture indicator stick readings in different sections of Oregon and Washington? If unpainted lumber is exposed to weather for a few years, its color changes and the grain shows as much erosion as if it were sandblasted. According to the Forest Products Laboratory, chemical as well as physical changes produce these effects. Repeated, unequal swelling and shrinking--caused by wetting and drying at the surface--distorts surface fibers and raises the grain. Sunlight, air, and water on the surface cause chemical changes that produce first brown then gray color and make lignin and cellulose partly soluble. Similar erosion and leaching of fuel-moisture-indicator sticks would cause a loss of weight and consequent inaccuracy.

Citation

Morris, William G. 1959. Effect of weathering on accuracy of fuel-moisture-indicator sticks in the Pacific Northwest. PNW Old Series Research Notes No. 171, p. 1-6