that on poor summer range, showed significant 
differences in fawn-doe ratios, percentage of 
multiple births, and productivity in the year- 
ling age class. Productivity in this youngest 
producing age class reflects range condition 
more sensitively than does productivity of 
older age classes. 
Hungerford (1964), in studies of Gambel’s 
quail in southern Arizona, found that late win- 
ter and early spring moisture was closely cor- 
related with breeding, rate of production, and 
survival of young birds. The early moisture in- 
duced production of green food, which, in turn, 
produced more vitamin A for storage in the 
liver. 
As stated previously, mortality is the most 
spectacular manifestation of poor-quality for- 
age. In the chaparral range of northern Cali- 
fornia, the principal period of mortality in 
deer is midwinter. Late summer and fall 
dieoffs occur after unusually hot summers. 
In either case the loss is associated with poor 
forage conditions and dietary deficiencies 
(Taber and Dasmann 1958). Swank (1958) 
found similar relationships of mortality to 
poor forage quality in deer studies in Arizona. 
Robinette et al. (1952), in studies on Utah 
ranges, found that winter deer losses varied in- 
versely with forage quality. In the Jawbone 
deer herd study, Leopold et al. (1951) found 
that deer had such a strong attachment to a 
home range that they would not shift to higher 
quality forage even to survive. 
Some forage species have a high nutritive 
content, but partly inhibit rumen micro-organ- 
isms (Dietz et al. 1962). Sagebrush, for exam- 
ple, is highly nutritious when fed in combina- 
tion with other browse species. However, when 
it is fed alone, it produces harmful effects or 
malnutrition. 
IMPROVEMENT OF FORAGE QUALITY 
THROUGH PRACTICES 
Timber Cutting.—Clearings for wildlife in 
extensive timber types are an accepted im- 
provement practice in the Eastern United 
States. This practice is widely used on Na- 
tional Forests and is used to a lesser extent on 
State and private lands. The principal objec- 
tive in making such clearings is to remove 
patches of the overstory so that sunlight will 
reach the herbaceous vegetation to increase its 
abundance and nutritional value for wildlife. 
Clearings also result in better composition of 
low-growing plants and afford opportunities to 
grow planted forage crops of high nutritional 
value for both deer and small game species. 
In hardwood forests, cuttings often produce 
vigorous stump sprouts palatable to deer. On 
the Pisgah National Forest, N.C., deer pre- 
ferred sprouts over the more abundant seed- 
lings (Moore and Johnson 1967). 
If properly planned, clearings resulting 
from timber sales can serve the same purpose 
as clearings made specifically for wildlife. The 
principal difference is that timber sale cuttings 
form transitory openings, lasting 10 to 20 
years, whereas clearings made specifically for 
wildlife are generally maintained as perma- 
nent openings. Clearings are expensive to es- 
tablish and to maintain. This indicates the 
need to plan and to utilize cuttings in timber- 
sale areas for their multiple benefits. 
On the Black Hills ranges in South Dakota, 
livestock showed a decided preference for for- 
age grown on open meadows compared with 
that grown under ponderosa pine. Studies of 
chemical composition of plants grown on both 
sites disclosed generally higher levels of pro- 
tein, crude fiber, calcium, and phosphorus in 
plants grown under timber. On the other hand, 
plants growing in the open had higher levels 
of nitrogen-free extract. The heavier grazing 
use in the meadows was attributed to the high- 
er percentage of nitrogen-free extract (Mc- 
Ewen and Dietz 1965.) 
Deer population estimates of the Forest Ser- 
vice indicate a 4-fold increase in black-tailed 
deer on the National Forests in Oregon since 
the mid-1940’s, when patch-cutting of Doug- 
las-fir timber got under way on a large scale. 
Even today, the preferred feeding areas in 
Douglas-fir stands are the recent clearcuts. Ex- 
cessive use on some clearcuts has delayed or 
even prevented reforestation. There has been 
similar improvement of quality of the deer 
range on logged areas of western Washington 
(Brown 1961). 
As a habitat improvement practice for deer 
and turkey, clearings are planned so that they 
complement natural openings or timber-sale 
cuttings. The objective on some National For- 
ests is to have up to 5 percent of the area in 
dispersed openings of 1 to 5 acres. 
In the Northeastern States, abandoned log- 
ging roads are seeded and maintained as 
grouse feeding areas as well as to facilitate 
foot travel by hunters. Rights-of-way for pipe- 
lines and powerlines are also utilized as clear- 
ings for wild life. 
Studies of forage under various levels of tree 
thinning indicate that production is inversely 
related to the basal area of pine stands; the re- 
lationship is usually logarithmic. In eastern 
Washington, the degree of thinning in over- 
story pine timber directly influenced the vege- 
tation (McConnell and Smith 1965). As the 
canopy was progressively opened by thinnings, 
the proportion of grasses increased linearly. 
Thinnings to a 40- to 45-percent canopy result- 
ed in equal increases of both grasses and forbs. 
