86 CLIMATIC CYCLES AND TREE-GROWTH 



The cycles are 6.8, 10.2 (2), 14.0 (3), 20.3 (oc. £ or £), 22.6 (2, oc. $), 

 and 28.3 (oc. •£). This is of mixed type and does not readily match 

 any one of the three zones. Its 14- and 20-year cycles remind one of 

 Arizona, but the 10-year cycle is strongly Rocky Mountain and the 

 one close to 23 years is most common on the Coast. There is prob- 

 ably some relation between this set of cycles and its position close 

 to the coast. 



KLAMATH FALLS GROUP (KF) 



This group of 12 increment-cores was received May 12, 1924, 

 through the kindness of Mr. H. B. Rankin, supervisor of the Crater 

 National Forest, near Klamath Falls, Oregon. They had been secured 

 in that forest at an elevation of 5,100 feet above the sea. They cross- 

 identified perfectly, and a few of them show likeness to some of the 

 trees in the Boise and Baker groups. Mr. Austin measured all the 

 specimens, using the long-plot method, and after standardizing, the 

 curve was smoothed by graphic Hann and is given in figure 6. It 

 presents no marked similarity to any other, though the Boise and 

 Baker groups have real touches of likeness. Yet all the while its inter- 

 nal cross-identification was perfect and its smoothed-curve variations 

 look entirely normal. Its cycles are 8.5, 9.6, 14.0, 15.5 (oc. - 1 ), 19.5 

 (oc. •£-), 24.2 (2, oc. •£), and 31.2 (2). This is a mixed set, but perhaps 

 has a little more resemblance to the Arizona area than to the others. 



A very fine 500-year pine record was sent me on July 23, 1925. The 

 tree had been cut by the Pelican Bay Lumber Company in the same 

 forest on the southwest quarter of section 35, township 29 south, 

 range 6 1 east, W. M., at 5,100 feet elevation and about 5 per cent 

 east slope. This tree does not readily cross-identify with the 12 cores, 

 and as it comes from a different place and is very old, it is reserved for 

 future discussion. 



PLUMAS COUNTY GROUP (CP») 



This group of 10 increment-cores from Meadow Valley was sent 

 me by Professor Emanuel Fritz, of the agricultural experiment station, 

 Berkeley, California. He says: 



" Meadow Valley is eight miles west of Quincy, and the borings 

 were collected in Township 24 North, Range 8 East. The region is 

 very mountainous, but Meadow Valley is an ancient lake bed. The 

 borings came from the southern border of the valley on a slope, less 

 than 100 feet above the valley floor, elevation 4,000 feet. The water- 

 supply is excellent and the soil is very rich in humus and carries con- 

 siderable moisture. The forest growth is comparatively luxuriant. 

 All the borings were taken in August, 1922." 



They cross-identified well and were measured by Mr. Cherry, 

 using the auto-plot method. They were standardized and smoothed 



♦"California pines," the first group of that species secured from California. 



