Decay and Termite Resistance of Medium-Density Fiberboards Made from Wood Residue

Fiberboards of approximately 45 lb./cu.ft. density were made from northern white cedar, mixed northern hardwood planing mill residue debarker scrap, hardwood sawdust, or mixed hardwood tree tops. The cedar and tree tops were chipped and with the other raw material run through a Bauer pressurized refiner. Boards were made using a urea-melamineformaldehyde adhesive with setting induced by high frequency energy in a heated platen press. Standard ASTM methods were used for evaluation of decay and termite resistance. Boards of a white cedar heartwood sapwood mixture were more resistant to termites than the controls of cedar or southern pine sapwood. The former were also more resistant than boards made of 50 percent cedar or all hardwood residue. White cedar heartwood was slightly more resistant than the all-cedar board. All boards were more resistant to decay caused by Lenzite trabea or Poria monticola than aspen or southern pine sapwoods but less resistant than northern white cedar heartwood. None of the woods or boards showed useful resistance to decay by Poria incrassata. Besides extractive content of boards made of cedar, hardness probably contributed to termite resistance.

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