4 20 



Yearbook^ of Agriculture 1949 



breaks be detected from lookouts and 

 vantage points. 



The technique finally developed to 

 detect the infested and killed trees re- 

 quired sample lines to be run through 

 the various areas and the trees viewed 

 at close range. Such a survey has been 

 made annually since 1944, with a crew 

 of three to six men. In addition, a close 

 watch for infestation has been kept 

 by the forest rangers during their sum- 

 mer travels. Although coverage has not 

 been so complete and thorough as one 

 would like, a fairly accurate picture 

 has been obtained of the progress of 

 the outbreaks. 



The spruce losses have been phe- 

 nomenal for such a short period. The 

 end of the losses on the White River, 

 Routt, and Arapaho National Forests 

 is not yet in sight. The surveys indicate 

 a serious flight of beetles from the cen- 

 ter of the White River National Forest 

 outbreak to the east across the Colo- 

 rado River into extensive spruce stands. 

 The outbreak on the Gore Range on 

 the Routt and Arapaho National For- 

 ests is rapidly moving northward. The 

 outbreak on these two forests has 

 gained much of its momentum from 

 flights of beetles across the Yampa 

 River Valley. 



A large beetle population remains 

 on the White River National Forest, 

 however, and the continuation of a 

 mass flight there is still not beyond pos- 

 sibility. In 1946, at the end of the at- 

 tack period, 77 percent of the spruce 

 was killed on that forest north of the 

 Colorado River. Nearly all the remain- 

 ing trees were killed in 1947. The 

 beetles have exhausted their food sup- 

 ply on the White River National 

 Forest, and whether they will perish 

 within the infested area or fly to new 

 areas remains to be seen. 



The outbreaks on the part of the 

 White River National Forest that lies 

 south of the Colorado River, and on 

 the Uncompahgre, Gunnison, and 

 San Juan National Forests in Colo- 

 rado, and the Dixie National Forest in 

 Utah started to decline in 1946. They 

 reached an endemic status in 1947, 



even though ample host material re- 

 mained for the insects to attack. 

 Natural control factors, aided by arti- 

 ficial control on the Dixie and Gun- 

 nison National Forests, reduced the 

 outbreaks faster than they arose. 



Active outbreaks continued in 1948 

 on the Grand Mesa National Forest 

 and on the Gore Range on the Routt 

 and Arapaho National Forests. Log- 

 ging of the infested trees and burning 

 of the infested slabs at the mill pre- 

 vented the Grand Mesa infestation 

 from becoming more severe. A similar 

 plan was applied to the Arapaho and 

 Routt infestations. 



IT WAS EVIDENT in 1943 that cutting 

 must be immediate if this beetle-killed 

 timber was to be used for lumber, since 

 it was doubtful if it would remain 

 usable for that purpose for longer than 

 3 or 4 years after attack. Every appli- 

 cation to purchase beetle-killed spruce 

 was granted. An aggressive campaign 

 was started to interest more operators. 

 Small operators soon began cutting in 

 most of the accessible areas. Lack of 

 capital and the difficulty of obtaining 

 proper equipment and labor kept pro- 

 duction low. 



Results have been disappointing 

 when weighed against the large volume 

 of killed timber. It was estimated that 

 by January 1949 about 100 million 

 board feet had actually been salvaged, 

 or less than 5 percent of the operable 

 volume of insect-killed timber. 



The 4-billion-board-foot loss of tim- 

 ber represents better than 20 percent 

 of the Engelmann spruce timber in 

 Colorado. The rough mountain terrain 

 and distance to railheads and markets 

 make about half of this timber inac- 

 cessible and nonoperable from an eco- 

 nomic standpoint. Much of the 2 

 billion board feet considered operable 

 actually requires the construction of 

 roads to make it accessible for salvage. 



Sparse populations, limited funds, 

 and the ruggedness of this mountain 

 country have governed the location of 

 routes of travel between communities. 

 Few roads have been built to open up 



