BALSAM FIE. 31 



Since the fruiting bodies of the fungi, or, as the lumbermen call 

 them, "punks" or "conks," appear on the fir after the tree is con- 

 siderably rotten, it is exceedingly hard to tell merely by the appear- 

 ance of the tree whether it is sound or not. Being short-Uved, 

 balsam fir at the age of 80 to 100 years is abeady old, and especially 

 susceptible to rot of any kind. Therefore one seldom finds an old 

 balsam that is perfectly sound. 



During the winter months balsam fir logs often have on cross 

 section a "glassy" or "icy" appearance, which some lumbermen 

 consider an indication of defect. When cut by the crosscut saw, 

 the wood shows irregular areas which are perfectly smooth and shiny 

 as if planed. A microscopical examination of the wood,^ however, 

 did not reveal any signs of decay in the smooth areas, and the struc- 

 ture could not be distinguished from that of the ordinary rough areas. 

 During winter the water present in the wood of balsam fir is 

 mostly frozen, and the shiny, smooth spots are therefore not due to 

 any disease, but to the frozen condition of the wood. That this is so 

 is further shown by the fact that the same section of wood when cut 

 in an unfrozen condition appears rough over its entire area. The ice 

 formed in the wood acts as reenforcing material and prevents tJie 

 usual tearing of the wood fiber. 



Balsam fir is very sensitive to fire. Its superficial roots are easily 

 aff'ected by surface fires, and the flames reach its cambium through 

 the thin, tender bark, killing the tree. In a balsam injured by fire 

 the lower foHage first turns brown, and finaUy the top. The dying in 

 some cases is very slow, but is none the less certain. 



Balsam fir does not suffer from windshake, but it is easily uprooted 

 and broken by wind because of its shallow root system and slender, 

 brittle bole. 



THE WOOD. 



GENERAL STRUCTURE. 



The wood of the balsam fir m external appearance is strikingly 

 like that of eastern spruce, and it is often necessary to go to the 

 gross and minute characters of its anatomical structure in order 

 to distinguish it. Balsam fir is ordinarily close-grained and, like 



1 Glassy Fir,, by Hermann von Schrenk. Sixteenth Annual Report of the Missouri botanical Garden, 

 pp. 117-120. St. I.ouis, Mo., 190.5. 



