Cubic-foot volume was computed for the sound- 

 wood content of stems only, from stump to 4-inch 

 tip inside bark, limbwood and bark excluded, of all 

 trees of or above the 6-inch (5.1 to 7.0 inches) 

 diameter class. 



The estimates cover all timber areas, including 

 farm woods, outside the platted limits of munici- 

 palities. Differences between present estimates and 

 previous estimates for given areas are due princi- 

 pally to depletion which has taken place between 

 the time the two estimates were made and to differ- 

 ences between present and previous cruises as to 

 standards and as to completeness, and in some 

 instances to insect losses that occurred subsequent 

 to the date of early cruises. 



Species Classification 



An estimate of total volume of living timber was 

 made and recorded separately for every species that 

 usually attains saw-timber size and character and 

 that was present in commercial types in quantity 

 measurable according to survey standards. In 

 some cases estimates were combined for pairs of 

 species having similar dendrological characteristics. 

 Western juniper and some hardwoods do not usually 

 attain saw-timber size in the ponderosa pine region. 

 Although not included in the board-foot volume 

 estimates, these species are included in the cubic- 

 volume estimates. 



The species for which volume was recorded are 

 given in the following list. The nomenclature used 

 is that approved by the Forest Service (77). 3 as 

 amended in a few cases by recent Forest Service 

 decisions. Species bracketed were recorded as one. 



Conifers 



Ponderosa pine {Pinus ponderosa) 



Sugar pine (P. lambertiana) 



Western white pine (P. monlicola) 



Lodgepole pine (P. contorta latifolia) 



Douglas-fir (Pseudotsuga taxifolia) 



Western redcedar ( Thuja plicata) 



Alaska yellow-cedar (Chamaecvparis nootkatensis) 



California incense-cedar (Librocedrus decurrens) 



Western hemlock (Tsuga heterophylla) 



Mountain hemlock (T. mertensiana) 

 I Grand fir {Abies grandis) 

 (White fir (A. concolor) 

 J Noble fir (A. nobilis) 

 {Shasta red fir {A. magmfica shastensis) 



3 Italic numbers in parentheses refer to Literature Cited, 

 p. 84. 



Pacific silver fir {A. amabilis) 



Alpine fir (A. lasiocarpa) 

 (Western larch (Larix occidentalis) 

 (Alpine larch (L. lyalli) 



Engelmann spruce (Picea engelmanni) 



Sierra juniper (Juniperus occidentalis) 



Broadleaf Trees 



Red alder (Alnus rubra) 



Bigleaf maple (Acer macrophyllum) 



(Northern black cottonwood {Populus trichocarpa hastata) 

 (Narrowleaf cottonwood (P. angustijolia) 



Golden aspen (P. tremuloides aurea) 



Type Definitions and Type Mapping 



The definition of forest-cover and land-use types 

 for an area as large and varied geographically as 

 the ponderosa pine region was a difficult problem. 

 Each type used in the survey had to have some 

 significance in forest management. Types had 

 to be within practical limits in number, and defini- 

 tions had to be such that types could be determined 

 from office records such as timber cruises and could 

 easily be recognized in the field and sketched on 

 field maps. Even in the primeval forests many 

 species associations occur and fire, cutting, and 

 land settlement make conditions more complex. 

 However, by employing as a base a type scheme 

 already in use by the Forest Service for intensive 

 surveys, a scheme was devised that has been 

 proved to be satisfactory. 



The forest-cover types recognized in the forest 

 survey of the ponderosa pine region are as follows: 



Woodland Types 



No. 4. Oak: A stand containing approximately 

 60 percent or more of one or more species of oak. 

 No separation of age classes. 



Nos. 5A and 5B. Juniper: A stand composed 

 principally of juniper, often with more or less 

 mountain mahogany. Not so classified: Land 

 where the trees are so scattered that they occupy 

 less than about 5 percent of the ground surface. 

 The two juniper types are classed by size and den- 

 sity; in the dense type (5A) the juniper trees are 

 so large or numerous that they occupy 10 percent 

 or more of the land area; in the scattered type (5B) 

 they are so small or scattered as to occupy between 

 5 and 10 percent. 



No. 5}i. Ponderosa pine woodland: A border- 

 line zone, with solitary trees, or groups of trees 

 too small to map separately, in which mature 



