238 Minnesota Plant Diseases. 



The subject of timber rots has in recent years been made the 

 object of special study by agents of the U. S. Department of 

 Agriculture. The following abbreviated account is based 

 largely on these reports. The importance of timber rots can be 

 realized in the consideration of the ties, fence posts, telegraph 

 and telephone poles, mine and ship timbers, paving blocks and 

 bridge timber which are all subject to conditions extremely fa- 

 vorable for decay, in addition to all other building timbers 

 which, though not under such unfavorable conditions, may still 

 undergo serious rotting. Efforts have been made at different 

 times for more than a hundred years to lengthen the "life" of 

 such timbers by various kinds of treatments. From the nature 

 of the case, long periods of time are necessary for carrying on 

 experiments in this line and a great deal of progress has not 

 yet been made. A number of satisfactory methods, however, 

 are known at present, but on account of the cheapness of timber 

 in this country have not until recently been introduced and are 

 not even yet extensively employed. 



In the first place seasoning of timber is an important factor. 

 Green timber contains more moisture, which is directly favora- 

 ble to the fungus growth and subsequent decay of the wood. 

 It must also be noted that different kinds of timber require 

 different lengths of time for seasoning. Beyond a certain point 

 seasoning does no good but may work harm. Even wood of 

 the same kind from different localities may require different 

 treatments. Seasoning, therefore, is not only an important fea- 

 ture but is also one which is not altogether simple. Its value is 

 beyond doubt, as has been shown by numerous experimental 

 results. Another feature which needs mention at this point is 

 the storage of the timbers. Close piling often results in closed 

 moisture-laden chambers, which easily encourage the growth 

 of fungi and the close contact of the wood admits of the rapid 

 spread of the decay from piece to piece. The drainage of 

 water is also seriously interfered with. Timbers, therefore, 

 should be piled so as to admit of as complete aeration as possi- 

 ble, so that each piece shall have the opportunity of thorough 

 drying out in proper season. The dangers of the storage of 

 contaminated timbers with sound timber have already been 

 mentioned. 



