SELLING LUMBER 



219 



when crushed between the fingers. This disease rarely extends 

 very far up into the trunk. In boards or timbers cut from the 

 butt end of the tree it frequently appears for from several inches 

 up to several feet. Emphasis should be placed upon the fact that 

 when the pine tree is cut, the organisms which cause the heart rot 

 and the butt rot defects die at once. In other words, in sawed 

 lumber the heart rot and the butt rot do not continue to develop 

 after the trunk of the tree is once cut up. These fungi differ 

 very materially in that respect from those which will be next con- 

 sidered. 



After the logs have been cut and lumber manufactured there- 

 from, the wood is liable to be attacked by a very much larger 

 number of fungi which cause different types of decay. The sap- 

 wood is extremely susceptible to the attack of these fungi, and in 

 most cases, where the conditions are at all favorable, will not 

 last more than a year or two. The heartwood, on the other hand, 

 in all species of Southern yellow pine is comparatively resistant 

 and has been known to resist decay for twenty years or more under 

 favorable conditions. 



There is much discussion at the present time whether the per 

 cent of resin in a piece of yellow pine indicates its power to resist 

 decay. The weight of evidence so far is that it does not, although 

 very resinous pieces have been known to last many years. 



All fungi which grow on lumber after it is cut from the tree 

 require certain conditions to develop. These are a certain amount 

 of heat, a certain amount of water, a certain amount of food sup- 

 ply, and a certain amount of oxygen. The exact proportions of 

 these physical requirements vary with the different species. This 

 may to some extent explain why in some cases one form grows on 

 yellow pine lumber and in other cases why this same form will not 

 flourish. 



One of the most important of these fungi is the one which 

 causes the so-called blue stain or sap stain of yellow pine lumber. 

 The blue stain fungus grows naturally in the forest on dead twigs 

 and trunks and produces countless numbers of spores which are 

 blown about throughout the entire country near a pine forest. 

 When freshly cut boards are taken to the yard millions of these 

 spores fall on such boards and during favorable months, par- 

 ticularly from March until October, they sprout with exceeding 

 rapidity and penetrate the sapwood, attacking the starch, sugar 

 and oils found in the sapwood, and oftentimes within twenty-four 



Rot in 

 Living Tree 

 Ends with 

 Cutting. 



Fungi That 



Attack 



Lumber 



Resin Does 

 Not Increase 

 Decay Re- 

 sistance 



The Origin 

 of Blue 

 Stain 



