232 PKINCIPLES OF AMERICAN FORESTRY. 



Sapwood Contains More Ready-Made Food in forms 

 acceptable to a greater number of kinds of fungi than 

 the heartwood. This largely accounts for the fact that 

 sapwood is much more liable to decay than heartwood. 

 This is especially true in the case of Cedar and Pine, 

 where the heartwood is protected by resinous substances. 

 But when the sapwood is well seasoned and heavier than 

 the heartwood it lasts as long. Wood that has been 

 once attacked by fungi becomes predisposed to further 

 decay. 



The Time of Cutting Timber affects its durability only 

 as the weather at the time of cutting affects the curing 

 process. Wood cut in summer is generally affected by 

 decay-producing fungi, rapid fermenting of sap, and by 

 bad checking, owing to very rapid curing on the outside. 

 As the cracks thus made go deep into the wood they may 

 increase the danger from fungi. Where summer-felled wood 

 is worked up at once and protected by kiln-drying, it 

 lasts as long as that cut at any other season. 



Early winter is probably the best time to cut timber, 

 as regards durability, since it then seasons slowly at a 

 time when the rot-producing fungi arc not active, so that 

 it can cure over on the outside before summer. Many 

 kinds of fungi and beetles find a very favorable place just 

 under the bark of logs. These can be avoided, the curing 

 of the timber hastened, and its durability greatly increased, 

 by removing the bark soon after felling. When trees are 

 cut in full leaf it is advantageous to let them lie at full 

 length until the leaves are thoroughly wilted (two or 

 three weeks) before cutting to size. With conifers this 

 is a good practice at any season, and while not practical, 

 yet theoretically all winter-cut trees should be left to leaf 

 out in the spring before being worked. In this way 

 most of the sap is evaporated, but in the care of timber 



