Increased Absorptiveness of Molded Douglas-Fir Posts

Wet, freshly cut and peeled Coast-type Douglas-fir posts 3 to 6 inches in diameter were sprayed with: a) 2 percent solution of sodium fluoride in water, b) 4 percent solution of equal mixture of sodium pentachlorophenate and borax, 2 percent sodium fluoride and Trichoderma spore innoculum, unsprayed control. Drying of sprayed and control posts was retarded for 70 days before final drying indoors to an equilibrium moisture content. Fungus, predominately the mold Trichoderma, infested posts except those sprayed with sodium pentachlorophenate and borax. Sections of dried posts were tested for permeability to a 50-50 solution of coal tar creosote-petroleum oil applied by soaking and hot-cold-bath methods. Absorption of creosote solution was 3 to 5 times greater in infected posts, similar increases in radial penetration were shown. Breakdown of parenchyma cells characterized infected wood and increased its permeability.

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