TREE RECORDS! GEOGRAPHICAL DISTRIBUTION 75 



the Rim and about halfway between Pine and Fort Apache. The 

 elevation is under 6,000 feet. The region is reached by motor from the 

 White River Indian School near Fort Apache. The cores were meas- 

 ured by Mr. Patterson, using the auto-plot method, and fully re- 

 checked. The curve, 1652 to 1919, was plotted directly from the 

 averages and cross-identifies closely with the Flagstaff record. The 

 graphic Hann from 1750 on is shown in figure 4. It resembles RL 

 strongly. The cycles are 8.2, 9.6, 12.1, 18.5, 23.8 (3), and 30.5. There 

 was no sign of a 14-year cycle, and therein it resembles the Rocky 

 Mountain curves. 



PINAL MOUNTAIN GROUP (PNL) 



Surrounded by the lower levels of southern Arizona, the Pinal 

 Mountains form an island 90 miles from the Rim groups described 

 above. To reach them from that part of the Rim, one motors down 

 Tonto Creek and after leaving Four Peaks on the right, passes Roose- 

 velt Lake and Dam. Twenty-five miles beyond are the cities of 

 Globe and Miami, south and west of which are the Pinal Mountains. 

 A road goes to Tucson over each flank. To the east is the Winkelman 

 road ascending almost to the pine level; to the west is the Globe- 

 Superior Highway, a splendid bit of road engineering over a rocky and 

 picturesque table-land. Four borings were made September 5, 1924, 

 above the camp-grounds, southwest of the main peak. These cores 

 were measured by Mr. Swan Erickson, using the long-plot method. 

 Each tree of the three usable ones was standardized and the resulting 

 curve (see fig. 4) shows distinct resemblance to the Flagstaff curve — 

 more in fact than do the curves of the other island mountains. The 

 cycles are 7.6 (2), 10.1, 14 (oc. •£•), 23, and 27. This grouping of cycles 

 is classed as general, since it is rather deficient in the special charac- 

 teristics of each zone. 



CATALINA MOUNTAIN GROUP (SC) 



The Catalinas are about 60 miles a little west of south from the 

 Pinals. They are a large, rambling mountain mass without distinctive 

 top and form an emphatic northern boundary to the Tucson Valley. 

 The main summit, Mount Lemmon, elevation 9,150 feet, has an 

 inconspicuous rounded top with a fire lookout. Close on its southeast 

 edge is the resort, Summerhaven, with an easterly ridge extending 

 4 or 5 miles to Bigelow Peak and beyond. Central on this ridge is the 

 beautiful little valley known as Bear Wallow, with the ranger station 

 and Soldiers' Camp. The SC group consists of eight increment-cores 

 and one 350-year v-cut, all usable except one core. Their location 

 extends from Summerhaven to Mount Bigelow. Some are on the very 

 crest of the ridge and some are a hundred feet or so lower down on the 

 south side. The average elevation is about 7,500 feet. The contours 



