TREE RECORDS: GEOGRAPHICAL DISTRIBUTION 83 



This curve, smoothed and shown in part in figure 5, distinctly re- 

 sembles the Flagstaff curves in position of the more prominent maxima, 

 but its cycles, 8.5, 16.8, and 35 (2), are characteristic of the Rocky 

 Mountain zone. 



BASIN MOUNTAIN LOWER GROUP (BML) 



The three v-cuts in this group were collected August 13, 1919, as 

 has been described in the preceding paragraph. Their actual loca- 

 tion was on the upper easterly slopes of Basin Mountain, some 500 

 feet vertically below the top. Thus climatically they are in the same 

 situation as the others, but with regard to soil moisture they are very 

 different, for they catch a local drainage. In fact, the lowest of the 

 three, No. H-29, had large complacent rings and could not be used. 

 The two remaining ones average 50 per cent larger growth than the 

 upper group. Mr. Freeman measured these with the cathetometer. 

 The curve, not standardized, begins at 1700 and ends 1918. The 

 smoothed curve from 1750 is shown in figure 5. The cycles are 10.5, 

 11.6, 13.4, 20.4 (oc. i), 22.7 (3), and 37, which resemble the Coast 

 cycles. 



AZTEC EAST GROUP (AE) 



On inquiry, Mr. E. H. Morris found that there were Douglas 

 fir trees nearer Aztec than the pines of Basin Mountain, namely, at a 

 point some 20 miles east. Accordingly, early in 1920 he secured four 

 specimens from there, H 39 to 42, which form this group. They showed 

 severe drought effects in several places, which made the dating of the 

 central parts uncertain, and accordingly later in the same year he 

 sent me five more, H 65 to 69, which gave entire certainty to the 

 dating. The earlier four were then measured by Mr. Freeman with a 

 micrometer slide, and the curve, 1662 to 1919, drawn without standard- 

 izing (as was the case with several of the early curves) and smoothed, 

 is «hown in part in figure 5. As with the others from this region, it 

 resembles the Flagstaff curves. Its cycles are 8.1, 12.4, 19.5, 24.0 (3), 

 and 34.2 (oc. ^-), which resemble both the Flagstaff and the Rocky 

 Mountain cycles. A later curve, using all these "Modern H" trees, 

 gives cycles as follows: 8.2, 13.7, 18.8, 20±, 23.8, and 36. 



THE COAST ZONE 



BOISE, IDAHO, GROUP (BI) 



This group is a set of 10 increment-cores sent by the forest super- 

 visor of the Boise National Forest, in July 1923. They came from 

 the southwestern parts of the forested mountains, some 50 miles 

 northwest of the city. The growth is complacent, but the cross- 

 identification of all 10 is good. Two of the trees cross-identify with 

 some of the trees from Klamath Falls, in southern Oregon. These 



