Table 4. --Basal area summarized for three areas examined that have 



sustained one or more mountain pine beetle infestations 



Tree : Dell : Moody : Pilgrim 



condition : Creek : Meadows : Mountain 



---------- Square feet --------- 



LODGEPOLE PINE 



Live 14.9 137.8 66.5 



Dead! 27.5 28.8 ' 46.8 



Dead^ -- 5.6 6.2 



Total 42.4 " 172.1 ' 119.5 



SUBALPINE FIR AND OTHER SPECIES 



Live 73.8 1.7 26.5 



Dead^ 17.0 



Total 90.8 ■•, 1.7 26.5 



ALL SPECIES 



Live 88.7 ^ 139.5 93.0 



Dead2 44.5 34.3 53.0 



Total 133.2 '■ 173.8 146.0 



^Killed by mountain pine beetle, 

 ^Other causes . 



the development of the fir understory as the lodgepole pine overwood was reduced by 

 repeated beetle infestations. Some mortality also occurred in the subalpine fir stand 

 as reflected by the 17.0 square feet of basal area recorded under dead trees in table 4. 



Moody Meadows . --Another lodgepole pine stand investigated by Roe near Moody 

 Meadows on the Rexburg District of the Targhee National Forest has been infested twice. 

 The first infestation occurred approximately 1937 to 1947. Some control effort, felling 

 and spraying infested trees, was applied in the stand in 1946 (figure 8). This first 

 infestation was light and was probably checked by the control effort or the beetles 

 were unable to sustain themselves in the thin-barked trees in the stand. But now, 21 

 years later, the same stand is reinfested and the latter infestation is more intensive 

 than the former--46.9 trees per acre killed in the current infestation as contrasted 

 with 17.7 trees per acre in the first. The present infestation has killed trees in 

 the 7- to 14-inch range amounting to 16.7 percent of the total basal area in the stand. 



Trees in the residual stand with diameters 4 inches and larger range from 54 to 

 106 years in age with a mean age of 87 years. Some lodgepole pine trees up to 16 inches 

 d.b.h. can be found in the stand. The Moody Meadows stand is stocked with 516 trees 

 per acre, 1 inch d.b.h. and larger, and these are distributed among diameter classes 

 as shown in figure 6. 



Residual lodgepole pine trees in the Moody Meadows stand show definite release as 

 illustrated by the upward trend in diameter following the 1937 to 1947 infestation 

 (figure 9). The release effect appears to be most pronounced in the larger trees, 

 particularly those that were located either in or near the margin of the openings 



12 



