TREE RECORDS: GEOGRAPHICAL DISTRIBUTION 81 



same way as the yellow pine and Douglas fir. While dating the records, 

 it was evident that the Engelmann spruce was giving a different 

 story and could not be joined with the firs and pines. So the brook 

 trees are separated into two groups, of which this one is made up of 

 4 firs and 2 yellow pines. One of these firs, PP-35, carries a dendro- 

 graph designed by Dr. D. T. MacDougal. The two yellow pines are 

 only a few feet away, and these three trees are sometimes referred to 

 as the dendrograph group; but they are themselves close to the brook 

 and their records agree well with the other Douglas firs near by, so 

 they make up part of this group. These six cores were measured by 

 Mr. Austin, using the long-plot method, and after standardizing gave 

 a curve from 1782 to 1919, which was smoothed in the usual way and 

 is shown in figure 5. This closely agrees with the other adjacent 

 groups already described, and with them (PPB, HNT, LNT, ST, and 

 C) forms a collection of homogeneous groups which must represent 

 this region exceedingly well. The cycles of the Douglas fir brook 

 group are 7.5, 9.5 (2), 11.4 (oc. £), 14.3 (oc. £), 20 - 4 ( 2 )> 22 -5 ( 2 , 

 oc. ■£), and 39, a good Rocky Mountain set. 



BROOK GROUP OF ENGELMANN SPRUCE (BES) 



Engelmann spruce growth on the San Francisco Peaks in Arizona 

 had been too complacent for use in climatic study, but on Pike's Peak 

 four trees, PP 28 to 31, along Ruxton Brook, showed attractive 

 variations and even exhibited weak signs of cross-identification 

 among themselves. But when the curves were drawn, it was seen 

 that their growth does not match the growth of the other brook 

 species. The cores were measured by Mr. Austin by the long-plot 

 method and standardizing lines marked on each individual tree-curve 

 by the writer, as always. The resulting smoothed curve, from 1775 

 to 1919, shown in figure 5, presents marked variations, departing 

 greatly from the typical Pike's Peak curve. Its cycles are 8.9 (2), 

 12.2 (2), 14.1 (2), 17.6 (£), 24.7 (oc. £), and 34 (oc. •£). The 17- 

 year cycle is characteristic of the Rocky Mountains, but the presence 

 of a 14-year cycle and a probable sunspot cycle make this set resemble 

 the cycles of the Coast zone. 



CLOUDCROFT. NEW MEXICO. GROUP (CC) 



Any real representation of the Southwest would be incomplete 

 without specimens from New Mexico's summer resort, Cloudcroft, in 

 the Lincoln National Forest. Accordingly, six good v-cuts from pine 

 stumps were sent me by Mr. Dan Felts, forest ranger there. Three 

 only could be used, and these, as Mr. Felts writes, come from the 

 northwest quarter of the southeast quarter of section 23, township 

 16 South, range 11 east, New Mexico prime meridian. This is the 

 extreme upper end of Nelson Canyon watershed, half a mile west and 



