TREE RECORDS: GEOGRAPHICAL DISTRIBUTION 73 



formed from the melting winter snow. Mr. Patterson measured 7 of 

 this group of eight v-cuts by the auto-plot method in 1922. Each 

 tree record was later standardized, tabulated, and plotted by Mr. 

 Austin in a curve from 1716 to 1919. This curve is of perfect Flagstaff 

 type. The graphic Hann shown in figure 4 was made by Mr. F. M. 

 Douglass in 1926. The cycles belong to the Arizona classification, as 

 follows: 11.7, 14.5, 18.4, 20.8 (2), 23, and 36 (oc. ■§•). 



DIXIE FOREST (UTAH) GROUP (DF) 



This is a group of Swedish increment-cores collected and sent me 

 by Mr. William M. Mace, supervisor of the Dixie National Forest, 

 from the Pine Valley Mountains, in the southwestern corner of Utah. 

 As in the case of the Charleston Peak of southern Nevada, it seemed 

 desirable to find some groups intermediate in position between the 

 Flagstaff area and the region of the big trees of California. Mr. Mace 

 writes that these specimens came from the westerly side of the moun- 

 tains at an elevation of 8,500 feet. This would seem to correspond 

 in topography to group FLH, but their record, though very complacent 

 like FLH, resembles FL more than FLH does. The cores were received 

 October 1, 1923. Mr. Austin measured them by the long-plot method 

 in 1926. Each tree was standardized and the table and averages and 

 plot were also made by Mr. Austin. The curve extends from 1616 to 

 1922 and shows good resemblance to the Flagstaff curve. It was 

 smoothed by graphic Hann and is thus shown from 1750 in figure 4. 

 Its cycles are of the Arizona type, as follows: 19.6 (3), 27.1, and 40 

 (2, oc. i). 



UPPER RIM GROUP (RH) 



Next to the Grand Canyon, Arizona's most remarkable scenic 

 feature, on a large scale, is the Rim. This is the abrupt southern edge 

 of the great Colorado Plateau. It is an ancient fault-line; the rocks 

 to the north average 7,000 feet above sea-level and 1,000 to 2,000 feet 

 higher than those to the south, with other steep slopes below, so that 

 from the Rim one looks over enormous stretches of Southern Arizona 

 with its island mountains showing faintly in the blue haze of distance. 

 The edge of the Rim stretches across half of the State in a generally 

 uniform direction, but is wavy or zigzag in detail. So, when seen from 

 below, for example, from near Pine or the Natural Bridge, its sinuous 

 length extending easterly as far as the eye can see, could be classed 

 as one of the wonders of the world. 



An extraordinarily large and pure pine forest covers this Rim and the 

 adjoining slopes, connecting on the north with the Flagstaff area and 

 extending on the east past the White Mountains and into New Mexico.* 



♦Years ago, by kindness of Mr. F. S. Breen, then supervisor of the recently created national 

 forest, it was my privilege to traverse this Rim from Camp Verde to Nutrioso, close to the New 

 Mexican border, in a buckboard. I have no doubt that 600-mile trip from Flagstaff, lasting 26 

 days, helped to originate this investigation of the history recorded in tree-rings. 



