Sitka spruce: uses, growth, management. 19 



pear at the base of the tree, on the trunk in old wounds, or on the 

 ground, coming up from decaj^ed roots. Those on the ground have a 

 short, thick stalk. The disease spreads both by spores blown about in 

 the air and through the ground by means of the decayed roots, The 

 decay which is confined to the heartwood is light reddish brown in 

 the early stages, and pronouncedly cubical, reddish brown, crumbling 

 to a fine powder between the fingers, and often with thin resinous 

 crusts of mycelium in the typical stage. The rot is found in the roots 

 and butt, and rarely extends beyond the first log. Besides the actual 

 loss due to the volume of wood rendered unmerchantable by decay, 

 the infected tree is frequently broken off at the base as a result of the 

 weakening of the roots. Many large overmature trees, completely 

 rotted at the base except for a thin layer of sapwood, are found broken 

 off between 5 and 20 feet above ground, and their loss can be charged 

 directly to the destructive work of this fungus. 



The red-belt fungus (Fomes pinicola) is of equal importance with 

 Poli/porus schweinitzii as a butt rot in living trees; but it is also 

 common on dead snags, old windfalls, stumps, and other debris, and 

 thus functions as a beneficial scavenger in the forest. The fruiting 

 bodies are usually found at the base of the tree in the flare of the roots 

 or at scars along the lower portion of the trunk. The typical decay 

 is light reddish-brown in color, somewhat cubical, crumbly and 

 brittle, with white feltlike layers of mycelium occupying the cracks. 

 Infection caused by this fungus is illustrated in Plate XVI, figure 1„ 



One of the most common fungi found on fallen Sitka spruce, be- 

 sides the red-belt fungus, is the lacquer-top fungus' (Ganode?*ma 

 oregonense) , readily recognized by the shiny, lacquerlike, reddish 

 upper surface of the annual fruiting body. This organism has not 

 been reported on a living spruce, but is often found on its associate, 

 the hemlock. There are a number of other fungi of less importance 

 which live on fallen trunks, but do not attack living trees. 



Sitka spruce is much freer from decay than either western hem- 

 lock or Douglas fir, but snags and down timber decay very rapidly. 

 The earliest infection appears in trees between 60 and 100 years of 

 age; only a slight amount of rot is found in stands between 150 

 and 300 years of age, and this is confined to the butts of trees. Over 

 300 years, or after maturity, however, the tops commonly break off, 

 and top rot as well as butt rot is very prevalent, becoming more 

 marked with age. It is not unusual, however, to find trees of 400 

 years entirely sound at the butt and with very little decay along the 

 trunk or in the top. In general, this species is remarkably free from 

 decay up to 200 years of age. 



The amount oi resin which the wood of a tree contains, or that 

 it is able to produce to cover any injury, affects its ability to ward 

 oft disease. Spruce, which has very little resin, is almost never able 



