20 BULLETIN 275,, U. S. DEPARTMENT OF AGRICULTURE. 



A systematic study of the relative position occupied by the heart- 

 rot factor in the economy of the forest presupposes a knowledge of the 

 morphology and biology of the specific fungi attacking the species of 

 which the forest is made up. Morphologically, most fungi of economic 

 importance are well known; biologically, there is much left to be 

 learned. The susceptibility of each host species to specific attack, 

 the age at which a given species becomes liable to attack by the 

 fungi adapted to live on it, the age at which a given species is liable 

 to suffer appreciable loss from this source, the relation of accessory 

 factors in the tree and outside T)f it to fungus growth, the relative 

 loss caused by each fungus in its specific host all these are funda- 

 mental problems which must be solved for every important fungus 

 on every commercial species of our forest trees. So far, no definite 

 and clear, comprehensive answer can be given to any one of these 

 questions. 



In determining upon a suitable starting point in the overwhelm- 

 ingly large amount of work before us, the question is that of deciding 

 where such work is most needed at the present time. 



Leaving out of consideration such species as bigtree (Sequoia 

 gigantea), which is never cut in national forests, and redwood (Sequoia 

 sempervirens) , which is hardly represented in national forests, the 

 commercial timber of the national forests in the western part of the 

 United States is composed of coniferous trees, such as pine, larch, 

 spruce, fir, Douglas fir, hemlock, incense cedar, and western white 

 cedar. They constitute the goods the Government has to offer for 

 sale. Of these the pines cause least trouble. Pine lumber is eagerly 

 sought and pays good prices; moreover, the loss from decay is com- 

 paratively small. In Government timber sales there is never any 

 difficulty about pine timber; the more the Government has to sell 

 on a given tract the better. Not so with the so-called "inferior 

 species." 



The term " inferior or undesirable species," as it is generally applied, 

 is originally not a technical one. It is meant to designate those more 

 or less heavily represented commercial species which suffer from a 

 distinct prejudice on the part of the purchaser. If we could grow 

 sound incense cedar, for instance, there would be a ready market and 

 a good price for every foot, board measure, of it that the Government 

 could offer on timber sales. Distinction should be made between 

 species which actually yield technically poor lumber, even if sound, 

 and species, on the other hand, which when clear and sound yield 

 valuable material, but which are in general underrated by the pur- 

 chasing public on account of the extraordinary prevalence of decay. 

 An example of the first class is eastern hemlock. An example of the 

 second class is incense cedar, which, although of excellent quality 

 when sound, suffers from a very bad reputation among lumbermen, 



