oe WESTERN YELLOW PINE IN ARIZONA AND NEW MEXICO. 
When yield tables are not available and it is desired to estimate the 
future growth on cut-over land, it is necessary to caliper a certain 
per cent of the stand left. Compute the average acre and the size of 
the average tree, and apply the average diameter growth for any 10- 
year period desired. As an example, Table 20 shows the average 
stand on eight selected acres on good soil in the Coconino and Tusayan 
National Forests. 
TABLE 20.—Averdge number of trees per acre of different classes in virgin 
forest before cutting. 










| 
Yellow pine. Blackjack. 
Diameter breast high.) 
| Diseased To be | Thinned 
| Sound. | to be cut. | Dead. saved. | to becut. Dead. 
Inches 
A= GB tee pe sie oe baie | 0.01 0.03 0.03 0.55 0.16 0.03 
[aOR a A ie ee ete .16 . 54 16 Sa2o - 26 09 
11(0 5 PAS te eee ere ne . 36 sou 20 3.16 oo 06 
IB Sb 6 sees cameo 1.02 26 11 2.41 5 1183 02 
MC es Sean Se Oca 1.92 39 21 1.74 al) 01 
1S EA) eS, Sipe ee eS 2.44 24 33 1 27/ -OL 03 
DOM ee ee aaa 2 Wee eD 31 50% Sus 02 uiltsae seers 
DO—D [pe eee oa eee 1.97 Pil 20 SUGen| Sees 01 
DS—SE il ferss e| 1.35 .19 21 04 03 01 
SESE ee hee ee eee ae 52 . 06 13 03) shasetenes es oe eee 
BER Meda een ae ee 45 .05 Ed een eared teammate Rhett Soe ob 
S1=09 as sae nes | .38 OL Sp FSRe eee Rae re ee es | eee 
ADR AD eee ead 51163 02s ieee ie, So OS | ee eee ee sea eee 
ASA aha i fees day pe Xe reel ae ey ma eee ae i | ee 
INDOWeN 25sec ee 12. 47 1.74 1. 64 6.13 34 08 
IADOVE WI See es ee | 9.53 1.09 | 1587 1.98 06 05 
a 



1 To be left for second cut in 20 years. 
Ordinarily in a Federai timber sale all the merchantable diseased 
yellow pine would be cut, as well as’the healthy yellow pine above 21 
inches in diameter, and the blackjack in need of thinning. The dead 
trees yielding saw logs would also be marketed. Of the trees over 12 
inches in diameter left on the ground, the average diameter for both 
blackjack and yellow pine is 17.8 inches. The stand over 12 inches 
in diameter left on the ground amounts to 1,054.3 board feet of black- 
jack, and 1,194.3 board feet of yellow pine, or a total of 2,249 board 
feet per acre. From Table 10 it appears that in 20 years the 17.8-inch 
blackjack will grow to 19.55 inches, and the 17.8-inch yellow pine 
to 19.15 inches. In addition, there wiil be trees of 12 inches and less 
in diameter that have in the meantime grown into the merchantable 
class. In 20 years the 11-inch blackjack will have a diameter of 14.30 
inches, and the 11-inch yellow pine one of 13.10 inches. This gives 
in 20 years a total stand of 3,093 board feet per acre, composed of 
1,418 feet of yellow pine and 1,675 feet of blackjack, a natural 
increase of 37.5 per cent, or about 2 per cent annually for the 20- 
year period. | 
The growth of stands will, of course, vary with the percentage of 
blackjack in composition. The more blackjack, the more rapid will 

