. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. Wash-cgloit, D. C. July 21, 1923 A STUDY OF DECAY IN DOUGLAS FIR IN THE PACIFIC NORTHWEST. By J. S. Boyce, Pathologist, Office of Investigations in Forest Pathology, Bureau of J*lant Industry. CONTENTS. Page. Importance of decay in Douglas fir 1 Method of collecting data 2 Fungi causing decay 3 Position of the decays in the tree 4 Relative importance of the decays 4 Mechanical injuries 5 Page. Entrance of the decays 7 Indications of decay in living trees 10 Extent of incipient decay
. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. Wash-cgloit, D. C. July 21, 1923 A STUDY OF DECAY IN DOUGLAS FIR IN THE PACIFIC NORTHWEST. By J. S. Boyce, Pathologist, Office of Investigations in Forest Pathology, Bureau of J*lant Industry. CONTENTS. Page. Importance of decay in Douglas fir 1 Method of collecting data 2 Fungi causing decay 3 Position of the decays in the tree 4 Relative importance of the decays 4 Mechanical injuries 5 Page. Entrance of the decays 7 Indications of decay in living trees 10 Extent of incipient decay 15 Summary 16 Outlook 17 Literature cited 19 IMPORTANCE OF DECAY IN DOUGLAS FIR. Douglas fir is the most important timber tree in the Pacific North- west, covering, as it does, the greater part of the foothills and lower slopes of the Cascade Mountains and the Coast Range in practically pure stands of great density. The stand of this species in Oregon and Washington is estimated at 505 billion feet (6, p. 23) / or nearly one- fourth of the remaining merchantable timber in the United States. The loss through decay in Douglas fir in this region is very high. While some overmature stands are relatively sound a loss of 20 per cent in such stands is not uncommon. In certain cases the cull figure may reach 50 per cent or more, so high that in timber on difficult ground it becomes impossible to log at a profit. It is only in young stands of second growth that Douglas fir is uniformly sound. Plate I shows defective trees left uncut after logging in an overmature stand. In this instance about 25,000 feet board measure per acre was left standing. Where clear cutting is practiced numerous logs and entire trees remain on the ground after logging, absolutely worth- less on account of decay. This is illustrated in Plate II. Practically all the large pieces were left because of rot. Recognizing the importance of this question, foresters and lumber- men in the Douglas fir region have repeatedl
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