DETEBIOEATIOX OF WESTEKN YELLOW PIXE. 3 



the tree is sound throughout, when as a matter of fact it ma} T be 

 commercially a complete loss through decay. Table 1 shows the 

 rate of deterioration. 



Table 1. — Rate of deterioration of felled western yellow-pine trees in Klamath 



County, Or eg. 



When cut. 



Volume (board feet). 

 Seasons 



Per- 

 centage 

 of cull. 



Trees with 



merchantable 



volume. 



Average 



diameter 



inside 



Num- 

 ber of 



posure. 



Gross. 



Cull. Net. 



Ppr- 

 Der - of total. 



bark | trees 

 stimip (basis), 

 (inches). 



1 



2 3 



4 



5 



6 



7 8 



9 



10 



April, 1921 



1 ! 6,400 



1 11.350 



2 11,610 



2 8,080 



3 15,870 



4 2,650 



5 . 35,510 



6 13,270 



7 11,470 



810 I 5,590 



13 



fi 100 



24 

 23 

 23 

 21 

 24 

 23 

 31 

 23 

 25 



6 



December, 1920 



February, 1920 



November, 1919 



Spring of 1919 



Spring of 1918 



April, 1917 



2,060 9,290 18 12 100 

 7,360 4,250 63 ; 11 79 

 6,120 1,960 76 i 6 75 



12,900 2,970 81 10 62 

 1,790 860 68 3 100 



28,960 6-550 82 ! 7 44 



12 

 14 



8 

 16 



3 

 Id 



Spring of 1916 



Spring of 1915 



12,060 

 10,710 



1,210 

 760 



91 



2 14 

 1 9 



14 

 11 



In Table 1 the expression " seasons of exposure " means the num- 

 ber of growing seasons that have elapsed since the trees were felled. 

 It is, of course, during the growing season that the greatest deteriora- 

 tion occurs, although loss continues throughout the year. This is 

 shown by the fact that the trees cut in April, 1921, and exposed for 

 one season show a loss of 13 per cent, while those cut in December, 

 1920, also exposed for one season but with four additional months 

 in winter and early spring, show a loss of 18 per cent. The same 

 relation holds for the trees exposed for two seasons but cut at dif- 

 ferent times. 



The important feature of Table 1 is the enormous increase in the 

 cull percentage after the first season. This increase is from 13 and 

 18 per cent for the first season to 63 and 76 per cent for the second 

 season and is so great that from an economic standpoint felled trees 

 must be utilized before they pass into the second season of exposure. 

 This means that the bulk of the trees cut on a control project must 

 be regarded as a loss, since it is at present commercially impossible 

 so to adjust logging operations that trees scattered over a large area 

 can be picked up in a single season. 



After the second season deterioration increases steadily, until by 

 the end of the seventh season there is little merchantable volume to 

 be obtained, and this only in an occasional tree much larger than the 

 average or with some other abnormal condition. For example, the 

 merchantable volume in the trees cut in 1916 came from two trees 

 only, as is shown in column 7 of Table 1. One of these was a large 

 tree with a diameter inside bark at stump height of 37 inches, while 

 the other, though 11 inches smaller in the same dimension, had an 

 unusually resinous butt log. The 760 feet board measure in the 1915 

 trees came from the first three logs in a 43-inch tree. 



The criticism may be made that Table 1 is based on insufficient 

 data. An examination of the table will show that the trees are well 



