VIEW ARTICLE

Source of Increased Decay Resistance in Sodium Hydroxide- and Ammonia-Treated Wood. T. L. Highley, Pathologist, Forest Products Laboratory, Forest Service, USDA, Madison, Wisconsin 53705; Phytopathology 63:57-61. Accepted for publication 18 July 1972. DOI: 10.1094/Phyto-63-57.

In tests that simulated aboveground exposure to promote low decay by brown rot, the increase in decay resistance in wood treated with ammonia or sodium hydroxide and heat was not attributed to destruction of the thiamine in the wood. The pH and the ammoniacal nitrogen content of the wood were found to affect decay resistance. When the pH of sodium hydroxide-treated southern pine (Pinus sp.) and sweetgum (Liquidambar styraciflua L.) was lowered by leaching in acid, decay by Poria monticola occurred. When ammonia-treated southern pine was leached in acid to lower ammoniacal nitrogen content, the wood was readily decayed by P. monticola.