VIEW ARTICLE

Physiology and Biochemistry

Influence of O₂ and CO₂ on Wood Decay by Heartrot and Saprot Fungi. T. L. Highley, Forest Products Laboratory, Forest Service, U.S. Department of Agriculture, maintained in cooperation with the University of Wisconsin at Madison; S. S. Bar-Lev(2), T. K. Kirk(3), and M. J. Larsen(4). (2)(3)(4)Forest Products Laboratory, Forest Service, U.S. Department of Agriculture, maintained in cooperation with the University of Wisconsin at Madison. Phytopathology 73:630-633. Accepted for publication 5 November 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/Phyto-73-630.

The effect of various partial pressures of O₂ (0.01, 0.1, 0.2, and 0.4 atm) and CO₂ (0.004, 0.1, and 0.2 atm) on decay in sapwood and heartwood by four heartrot fungi (Phellinus everhartii, Ph. igniarius, Ph. ferrugineofuscus, and Inonotus glomeratus) and three saprot fungi (Ph. ferreus, Ph. ferruginosus, and Poria medulla-panis) was studied to determine whether heartrot fungi possess ligninolytic and cellulolytic systems tolerant of low O₂ and high CO₂ levels. Decay caused by both groups of fungi was reduced by low O₂ (0.01 and 0.1 atm) and high CO₂ (0.1 and 0.2 atm). Increasing O₂ partial pressures above 0.1 atm enhanced decay by the saprot more than by the heartrot fungi. The saprot fungi were generally more selective in lignin removal than were the heartrot fungi. It is concluded that the unique ecology of the heartrot fungi is not attributable to an unusual ability to decompose wood at the high CO₂ and low O₂ concentrations found in the hearts of living trees.