2 BULLETIN 1140, U. S. DEPARTMENT OF AGRICULTURE. 



proximately 16,000,000 feet board measure, over an area roughly of 

 200,000 acres. Further work in the next three or four years .will 

 probably involve cutting an additional 20,000,000 feet of merchant- 

 able timber on adjoining areas. These trees must be left on the 

 ground until such time as they can be reached by logging operations. 

 The rate of deterioration of this felled timber then becomes of para- 

 mount importance. It is in connection with this project that the 

 study reported here Avas made. 



METHOD OF COLLECTING DATA. 



Local control work has been carried on in this region for some 

 years by the Klamath Forest Protective Association, and records 

 of this association were available, giving the general location of 

 trees felled yearly since 1915. From these records, felled trees were 

 relocated and examined during November, 1921. 



Each tree was opened up sufficiently with ax and saw to permit 

 scaling in 16-foot logs with the Scribner decimal C scale, according 

 to standard commercial practice. Logs two-thirds or more unmer- 

 chantable by volume were culled. Diameter measurements were 

 taken to the nearest inch, and length measurements to the nearest 

 tenth of a foot. The gross scale where given is the actual merchant- 

 able volume in the trees at the time of felling, determined when this 

 study was made. In making the measurements of decay, the subse- 

 quent advance of decay present in the living tree at the time of fell- 

 ing was disregarded. In the region in which the trees were stud- 

 ied the decays in living yellow pine seem to advance very slowly or 

 not at all after an infected tree is felled. Characteristically, west- 

 ern yellow pine is a sound species, and the normal loss through 

 decay in stands of living trees does not exceed 2.5 per cent and may 

 be much less. The only two kinds of decay found in the trees ex- 

 amined which were there at the time of felling were rots caused by 

 the ring-scale fungus (Trametes pini (Thore) Fr.) and brown cu- 

 bical butt-rot caused by the velvet-top fungus (Polyporus schwei- 

 niizii Fr.). Two trees had been infected with the first-named rot, 

 with a slight loss resulting. Brown cubical butt-rot had also been 

 present in two trees, but there was little indication left of the decayed 

 wood, which had been almost completely destroyed by fire when the 

 bark removed from the trees was burned. 



Data were obtained on a total of 100 trees, all western yellow pine, 

 near Bly, Klamath Falls, and Keno, in Klamath County, Oreg., at 

 elevations around 6,000 feet above sea level. The site conditions 

 were essentially the same for all the localities. These trees varied 

 from 16 inches to 43 inches in diameter outside bark at stump height, 

 and the usual stump height ranged from 21 to 3 feet. 



RATE OF DETERIORATION. 



These felled trees deteriorate with extreme rapidity, far more 

 rapidly than the casual observer is led to believe. The heat from 

 burning the bark and from the sun's rays results in a pronounced 

 drying of the outer sapwood to depths averaging one-half inch. 

 This outer layer, being too dry to decay, remains hard and sound 

 for several years, and if tested superficially leads to the belief that 



