30 TIMBER ROT CAUSED BY LENZITES SEPIARIA. 



service in the country. It alone probably destroys nearly one-fourth 

 of these timbers. The latest statistics show that coniferous ties and 

 poles bought in 1908 cost $32,500,000, making an annual item of more 

 than $8,000,000 worth of timber which has its length of service 

 seriously shortened by this fungus. 



Lenzites sepiaria is widely distributed, being prevalent throughout 

 Europe, in AustraHa, in the East Indies, and in South America. In 

 North America it is undoubtedly present throughout Canada to the 

 northern tree hue, everywhere m the United States, and at least in 

 the coniferous forests of Mexico. It occurs on the wood of Popidus, 

 Salix, Alnus, Abies, Larix, Picea, Pinus, Tsuga, Pseudotsuga, and 

 Juniperus. It is a saprophyte, but under certain conditions can 

 attack wood that is apparently alive. It usually enters timbers 

 through season cracks and under favorable conditions is able to form 

 mature sporophores within five months' time on newly cut tmiber. 

 The fungus has been known in Europe for many years, being easily 

 traced back to 1786. The sporophores are rather small, usually 

 occurring in groups or fusing laterally. They may revive after long 

 periods of desiccation, the writer having obtained spores from speci- 

 mens after two years. The spores are given off by hundreds of mil- 

 lions. Hence, decayed timbers should be destroyed, as they are a 

 prolific source of infection for new timber. Mature sporophores may 

 be produced within to 10 days after the first mycehum shows on 

 the exterior of an afi'ected timber. ;Many pure cultures have been 

 made by the writer, usually using the living mycelium instead of 

 spores for inoculation. Inoculations into green timber produced 

 sporophores within five months' time in Texas. 



The decayed wood is brown in color, irregularly fissured into tiny 

 cubical masses which crumble into dust between the fingers. 



Microchemical tests show that the lignin has lost some of its con- 

 stituents and is disorganized. Pure cultures grown upon sterihzed 

 green wood have produced the decay which constantly accompanies 

 the fruiting bodies in the field and forest. 



The factors governing the growth of wood-rotting fungi are food, 

 air, water, and temperature. These fungi cause decay by disorgan- 

 izing the wood tissues in which their mycelumi vegetates, and the 

 above factors which govern their growth consequently govern the 

 decay caused by them. Hence, the decay caused by Lenzites sepiaria 

 may be prevented or greatly retarded (1) by seasoning, which 

 decreases the water content of the timber to such a point that fungi 

 can not readily grow; (2) by floating, which excludes the air and 

 proba])ly has some effect on the food materials within the timber; 

 and (3) by chemical treatment, which infiltrates the wood with sub- 

 stances deleterious to the fungi. 



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