Influence of moisture on rate of decay of loblolly pine root wood by Heterobasidion annosum

Abstract

Root segments of loblolly pine (Pinus taeda L.) were decayed by Heterobasidion annosum (Fr.) Bref. (=Fomes annosus (Fr.) Karst.) over a broad range of wood (33–317%) and soil (36–259%) moisture contents in modified soil-block tests. Maximum weight loss occurred at 50–286% wood moisture content. Decay was inhibited at wood moisture contents over 290%. Water moved rapidly into the root segments by capillarity, and some decay occurred within 2 weeks. Water uptake was faster in inoculated segments than in noninoculated segments at a soil moisture content of 172% of the 0.2 bar (1 bar = 100 kPa) moisture content.