94 WESTERN YELLOW PINE IN ARIZONA AND NEW MEXICO. 
TABLE 11.—Diameter of western yellow pine breast high on the basis of age, 



i Annual 
Apache | Prescott | Jemez Zuni Datil Meo | Aaa 
Age.l from | ment for 
Forest. | Forest. | Forest. | Forest. | Forest. SiO. last 20 
years. 
Years. Inches. Inches. Inches. Inches. Inches. Inches. Inch. 
20 eee eerste 2.6 2.8 4.0 Pn, 2.0 2.6 0. 130 
AQ) lnk i roe ts by 72 6.1 8.2 4.6 4.2 5.8 . 160 
GOR2 eee 8.0 9.4 12.3 foil 6.6 8.7 . 145 
SOR Raa LOW 12.0 15.8 9.4 8.8 11.4 a bs) 
OOS Se aie 13.4 14.1 18.6 ie) 10.8 Bi, 7 .115 
20 RS nonce ek 16.0 16.2 20.8 16}, 77 12.5 15.7 . 100 
AO see yore 18.5 18.0 22.8 14.6 13.9 17.5 . 090 
GOR eee aoe 20.9 19.4 24.6 15.9 15.0 19.0 075 
SON ee Dane, 20.5 26.1 16.9 15.9 20.2 . 060 
OO Re eee 25.3 21.6 27.6 17.8 16.7 PNG S3 055 
7A) ests tae pe Dai fest: lal Visage og ee | LSE eee ee Ba 18.7 17.4 223 . 050 
DA re ee PAD BOs: (eee hs ey er nonce 19.5 18.0 Dol . 040 
PAG OEY Aaa gen SOE eee be eas | ey ernest 20. 2 18.6 23.8 - 035 
280 ee BQ Oy od eete ke el Reena aes 20.9 19.1 24.5 - 035 
S002 Re eee SOHO | eceeeeny ae ete es et sre wil. 7 19.5 25m 030 
Mean.... . 1130 . 1080 . 1380 . 0723 . 0650 SUSStN) Wecsccsssoc | 





162 years allowed for stump height. 
VOLUME GROWTH. 
Volume tables for western yellow pine are given in the Appendix. 
The increase in volume of single trees can be computed readily for 
a given number of years by applying the diameter growth, Tables 
9, 10, or 11, to a tree of known diameter; and by finding the volume 
of the tree, Tables 29 to 32, on the basis of present and future di- 
ameters. The difference between the two trees represents the volume 
increment. It is often desirable to apply the increase in height 
and read the present and future volume from the diameter-height 
volume tables. 
THE YELLOW-PINE TYPE. 
The typical western yellow pine forest of the Southwest is a pure 
park-like stand made up of scattered groups of from 2 to 20 trees, 
usually connected by scattering individuals. Openings are frequent, 
and vary greatly in size. Within the type are open parks of large 
extent, whose origin may be due to peculiar soil conditions, such as 
hardpan, or in other cases to periodic flooding. What is known as 
Garland Prairie, in the Coconino National Forest, contains some 
16,800 acres of rolling, open land. In a timber-sale area of 9,250 
acres on the Tusayan National Forest, bordering the woodland type, 
and with a westerly and northerly exposure, 6,609 acres were for- 
ested, while the remainder, about one-third of the total area, was | 
open land. At the lower limits of the yellow-pine type, pinion, alli- 
gator juniper, cedar, cypress, Gambel oak, and other woodland 
species occur in mixture with the pine. At the higher elevations | 
ure Douglas fir, white fir, limber pine, Mexican white pine, Engel- 





