1902. 



FORESTRY AND IRRIGATION. 



61 



young trees of the Bull and lyodgepole 

 Pines in Idaho ; others grow only in 

 the heartwood of living trees. Such a 

 one is shown in Fig. 3. It is the large 

 brown punk ( Tranietes pini) found on 

 all pines (here shown on the Shortleaf 

 Pine Pi)ius echinata). This fungus 

 makes the doty wood (Fig. 4), the first 

 stage of which is called ' ' red heart ' ' 

 b}' timber men. It destro3'S enormous 

 quantities of timber every year. Some 

 trees are attacked more than others. 

 Forty per cent, of the Red Fir in cen- 

 tral Oregon is diseased because of this 

 fungus, while the mountain pine of 

 northern Idaho is so badly diseased that 

 it is often impossible to find a tree en- 

 tirely free from it. The spores of this 

 fungus are blown about in the forest, 

 and get into wounds caused by the 

 breaking off of branches. Older trees 

 alone are attacked, as it is only in these 

 trees that the branch has formed heart- 

 wood. 



One fungus {Polyporus schzceinitzii) 

 enters coniferous trees throvigh the 

 root. It is the cause of the ' ' butt rot ' ' 

 of the older trees. The heartwood has 

 turned into a dry, brittle mass, which 

 may extend from one to sixty feet up 

 the trunk. Trees affected with this 

 disease usually break off near the 

 ground during storms. 



A distinct class of fungi grows only 

 on dead timber. Their spores alight on 

 the outside of a dead tree, and as the 

 fungus grows into the wood it destroys 

 the same. Fig. 5 shows a section of 

 one of these trees, a Bull Pine from 

 vSouth Dakota, killed by fire three years 

 ago. It will be noted that on the north 

 side, where the bark prevented the 

 rapid dr3dng of the wood, one of the 

 wood-destroying fungi entered and de- 

 cayed the wood in a very short time. 



The decay of railway ties, bridge and 

 mine timbers, fence posts, etc., is caused 

 by a number of these fungi. When 

 placed in positions where these timbers 

 are left moist, decay will set in from the 

 outside. This decay makes it necessary 

 to remove timbers frequently, involving 

 the cost of removal as well as the cost 

 of a new timber. When one reflects 

 that white oak railway ties last on an 



FIG. 2. RUST FUNGUS ON SEEDIJNG BULL 

 PINE. 



average onl}' eight years, it is easy to 

 understand what an enormous amount 

 of destruction these fungi do. 



One of the great problems of todaj- is 

 to find how one may prevent the de- 

 struction of timber by these fungi. 

 The trees in the forest when once at- 

 tacked cannot be saved. In some places 

 where permanent lumbering operations 

 are being carried on it wall be possible 

 to cut down all diseased trees, so as to 

 save at least a portion of the tree. This 

 cutting down will prevent the formation 

 of fruiting bodies, the spores of which 

 might infect other trees. In Germany, 

 where systematic forestry has been car- 

 ried on for many years, it is difficult to 

 find a diseased tree at this time. As 

 older trees are the ones usually attacked, 

 it follows that when we once know 

 where the danger limit begins, it will be 

 desirable to cut all trees which reach 

 that limit. 



