B. r. I.— C54. 



THE TIMBER ROT CAUSED BY LENZITES 



SEPIARIA. 



INTRODUCTION. 



The value of the total timber and wood cut in the year 1908'^ in the 

 United States was slightly more than $1,000,000,000. About three- 

 fourths of this immense production was supplied by the coniferous 

 si)ecies of trees. A large proportion of the timber used in heavy con- 

 struction, such as bridges, railroad ties, trestles, etc., is coniferous. 

 One may obtain a slight idea of the enormous quantity of coniferous 

 timber that is required from the fact that untreated coniferous rail- 

 road ties last only from 1 or 2 to 10 years, according to their conditions 

 of use, the average length of service being about 7 years. Because of 

 the great aggregate values involved, any factor which influences the 

 length of service of this timber becomes a matter of primary import- 

 ance. This is especially true at tlie present time when we are threat- 

 ened with a shortage of timber of all kinds. The most important 

 factors affecting the length of service of coniferous timber when 

 exposed to the weather or in contact with the soil are the wood- 

 rotting fungi. These greatly shorten the period of usefulness of such 

 timber and thus help to increase the already too great demands upon 

 our forests. 



While tliere are dozens of wood-rotting fungi which attack conif- 

 erous wood, certain ones are especially i)revalent and destructive in 

 their action. Lenzites sepiaria (Wulf.) Fr. and Lentinus lepideus Fr. 

 are probably the most widespread and injurious in this country. 

 The former is most destructive in the southern part of the country, 

 wldle the latter is very prevalent in the northern part, although both 

 are widel}'^ distributed in both sections. Lenzites sej>iaria is common 

 wdierever coniferous timber grows or is used. In the north the 

 climatic conditions are such that peeled timber will season before the 

 fungus can get well started in its growth, but it succeeds in causing 

 the decay of unpeeled timber. 



In spite of the economic importance of this fungus, not only in 

 America but in Europe, no publication, so far as the WTiter knows, 



"Bureau of the Census, Forest Products, vol. 10, p. 5, 1909. 

 214 7 



