capability of from 20 to 50 cubic feet of wood 

 per acre per year. A major problem in relation 

 to productivity is at the lower elevational fringe 

 of the forested zone. Much of this land simply 

 will not support enough trees to meet the pro- 

 ductivity level required for commercial forest. 



Another major factor affecting timber in- 

 ventory on this unit is the changing land use. 

 Pressure on the Forest by people is increasing 

 rapidly and as a result, an ever-increasing 

 amount of forest land is being devoted to non- 

 timber uses. 



Summary of the Coconino 

 National Forest 



Normal timber inventory procedure. — The 

 Coconino National Forest was studied at the 

 same time it was being reinventoried for tim- 

 ber. As a consequence it is possible to directly 

 contrast the study criteria and the land classifi- 

 cation criteria applied in the reinventory . 



The primary aerial photo point sample 

 taken on the Forest involved 8,300 samples. 

 Following is the estimate of area by broad land 

 class based on those samples. 



Land class Acres 



Productive forest land 902,522 



Unproductive forest land 516,390 



Nonforest land 355,798 



Total 1,774,710 



A subsample of 271 photo point samples 

 was drawn for field checking of land class and 

 measurement. The results of the field classifica- 

 tion were then used to correct the primary sam- 

 ple estimates. As a result of the field check, 24 



Land class 



Category A (commercial): 



Full yields expected 

 Modified yields expected 

 Total — Category A 



Category B ( marginal ) : 

 Currently inoperable 

 Fringe and low site areas 

 Total — Category B 

 Total — Timber Growing Base 



samples classed as productive forest land on the 

 aerial photos changed to nonproductive. In 

 other words, 24 of the field samples did not 

 meet the productivity criteria of 20 cubic feet 

 of wood per acre per year because of low site. 

 Following are the corrected estimates of area 

 by broad land class : 



Lzmd class Acres 



Productive forest land 854,355 



Nonproductive forest land 564,431 



Nonforest land 355,924 



Total 1,774,710 



Study criteria applied. — Using the addi- 

 tional data collected on stocking capability, it 

 was possible to more realistically assess land 

 productivity. In addition, it was possible to use 

 available soil data for identification of land 

 that, whUe supporting some timber, was from a 

 soil point of view alone, not to be considered 

 timber growing land. Also, it was possible to 

 use available vegetation type information for 

 identification of areas where the soil was ade- 

 quate, but because of moisture limitations was 

 not suitable to produce commercial tree 

 species. 



Productive forest land in the crest zone was 

 considered unsuited for timber use. Also con- 

 sidered unavailable for timber growing was pro- 

 ductive forest land in the special multiple use 

 zone, including such things as experimental 

 areas and designated natural areas and land in 

 management units managed primarily for non- 

 timber uses. Following are the results of ap- 

 plying the study criteria : 



Area in acres 



436,702 

 41,267 



477,969 



67,804 

 22,888 



90,692 

 568,661 



36 



