CELL WALL DOMAIN AND MOISTURE CONTENT INFLUENCE SOUTHERN PINE ELECTRICAL CONDUCTIVITY
Keywords:wood-moisture relations, electrical properties of wood, timber physics, percolation theory, wood damage mechanisms
Recent work has highlighted the importance of movement of chemicals and ions through the wood cell wall. Movement depends strongly on moisture content and is necessary for structural damage mechanisms such as fastener corrosion and wood decay. Here we present the first measurements of electrical resistance of southern pine at the subcellular level as a function of wood moisture content by using a 1 µm diameter probe. Measurements were taken with the probe contacting the S2 layer of the cell wall and the cell corner compound middle lamella in the latewood and the cell corner compound middle lamella in the earlywood. The resistance decreased with increasing relative humidity in all locations. The resistance decreased more rapidly with relative humidity in the S2 layer than in any of the middle lamellae. These results give insight into how some moisture-dependent wood properties affecting ion movement may be partitioned across cell wall layers.
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