Trees and Timber 371 



of the tree rise the numerous white-gilled, honey-colored 

 sporophores, their viscid tops flecked with white; the stems 

 swollen and with a ring (annulus). 



This disease may spread for long distances through the 

 soil by means of the fine roots and infect neighboring trees. 

 Upon newly cleared land diseased roots of forest trees may 

 be a source of infection to fruit trees subsequently grown 

 thereon. The disease is common to both conifers and de- 

 ciduous trees and has been particularly troublesome on oak, 

 pine, chestnut, larch, sycamore, poplar, locust, hemlock, 

 birch, alder, maple, and orchard trees. 



Red-rot ^^^ {Forties annosus Fr.). — Though not very de- 

 structive in this country, this fungus has been found on 

 pine, spruce, fir, and other conifers, more rarely on deciduous 

 trees, where it brings about a brown or red-rot of the root 

 system, which ultimately results in the death of an affected 

 tree. The fruiting bodies form small, cup-shaped shelving 

 or irregular masses on the roots or around the base of the 

 trunk. The fungus has also been found gi'owing on old, dead 

 trees. Neighboring trees generally become infected from a 

 diseased tree, through the small fibrous roots. 



Red-brown Root-rot '■^^^ (Polyporus sckweinitzii Fr.). ^ 

 A destructive root-rot of spruce, fir, arbor-vitae, hemlock, 

 larch, and pine, by weakening tlie rocjt or trunk, leads to the 

 overthrow of the tree by wind. 



The point of attack is always the root, through the heart 

 of which invasion is made into the trunk. This often leads 

 to one-sided decay of the trunk's heartwood. The wood is 

 rendered brittle, yellow, and later of cheese-like character, 

 so that it can readily be cut cross grain when wet or reduced 

 to a powder when dry. 



The pore-bearing sporophores, which appear in July or 

 August, are from 10-35 cm. across, growing either from the 

 roots or the trunk. If from the trunk, they are sessile; 

 from the roots they are stalked. The fresh spore layer is rose- 

 colored, and turns dark red if bruised. 



This disease is very common throughout northern for- 



