HOW WOOD IS PRESERVED 149 



decay above the ground level but just at the point where 

 they enter the ground they become soaked with moisture 

 and rapid decay takes place. Wood when used green and 

 full of sap is extremely inviting to fungi because in addi- 

 tion to moisture the sap contains starches and sugars 

 which supply the agencies of decay with plenty of food 

 for their development. The seasoning of timber not only 

 adds greatly to its durability but also increases its 

 strength to a marked degree. 



In some cases timber is allowed to season in the log 

 but as a rule, seasoning in the round is due to an over- 

 supply of logs rather than to intention. When logs 

 have been sawed into planks greater surface is exposed 

 to the air and consequently the seasoning process is 

 more rapid. The change in strength and durability 

 after seasoning is not alone due to the loss of a certain 

 amount of water but in addition there are certain 

 changes in the cell walls. 



The seasoning of lumber is an extremely important 

 part in its manufacture and sawmill men select the 

 location for their mill with great care. Timber may 

 "be ruined by poor seasoning or at least the grade of 

 the material may be lowered, thereby decreasing its 

 value. If the mill site has been unwisely chosen so 

 that free circulation of air is impossible, material may 

 season very poorly and a fungus growth like "blue 

 stain" will be extremely common with certain species 

 ^hich will spoil the appearance of the valuable grades. 

 The length of time which timber is allowed to season 

 in the pile depends much upon the species. Conifers 

 will be well seasoned in from three to six months while 

 hardwoods require close to a year for perfect seasoning. 

 Manufacturers very often will ship lumber before it is 

 wholly seasoned for by removing a part of the water 



