only limited quantities of timber of low quality because 
forest soils, like all others, vary in productive capacity. 
The combined effect of soil, climate, slope, exposure, 
and other factors is measured by site quality. 
The site quality of forest land was measured in two 
ways; for the pine lands of the Coastal Plain and Pied- 
mont it was based on the height of average dominant 
pine trees at 50 years of age (site index) ; for all hard- 
woods in the State and pines in the mountains it was 
based on merchantable height, tree form, and soil and 
moisture conditions. Pine sites were considered good 
if the site index was 80 feet or above, fair if 60 to 79 
feet, and poor if less than 60 feet. Hardwood sites 
were considered good if the merchantable trees, exclu- 
sive of yellow-poplar, averaged three or more 16-foot 
logs, fair if they averaged 1.5 to 3 logs, and poor if they 
averaged less than 1.5 logs. Longer merchantable 
lengths were required in yellow-poplar, pine, spruce, 
and hemlock in the mountains. 
In the Coastal Plain 22 percent of the forest land 
_ was rated as of good site and 68 percent as of fair site, 
_a total of 90 percent that was of satisfactory produc- 
tivity (table 5). This is a much higher proportion 
than in the rest of the State. The deep soils, abundant 
moisture, and lack of erosion in the Coastal Plain ac- 
count for the better growing conditions. In the Pied- 
mont, on the other hand, only 8 percent of forest area 
was of good site, and 69 percent was of fair, a total of 
77 percent of satisfactory productivity. Rapid and 
severe deterioration of soil following land abuse is the 
_ major cause of lower site values in the latter province. 
Taste 5.—Distribution of forest area by physiographic province and 
site class, 1940 
Physiographic province Good Fair Poor 
Percent Percent Percent 
Goustal bl arm iace tage eee ie ey tee ee 22 68 10 
Piedmon tease ete ace eee eth ees ES cis 8 69 23 
PTO yin cali ee veer peice ae ee se 3 74 23 
Al iiprovincesm es seep ee eee 10 71 19 
In the mountains only 3 percent of the area was of 
_ good site, but 74 percent was of fair. Good sites are 
rare because of the effects of topography and thin soils. 
In general they are confined to the lower north slopes, 
coves, and narrow valley floors. Except for the upper 
coves, these locations are commonly put in cultivation 
or grass pasture, reducing still further the forest area 
in the good-site class. 
Virginia Forest Resources and Industries 
825098°—49 4 
Stocking 
The relation of the density of the average stand in 
terms of volume in cords per acre to the density of 
the best 10 percent of stands is referred to, in this 
report, as stocking density. Data are available only 
for the Coastal Plain and Piedmont. In the former, 
the average pine stand was only half stocked (fig. 29), 
containing 18 cords per acre as contrasted with 36 
cords for the best 10 percent of the stands. Degree 
of stocking varied only slightly from age class to age 
class, ranging from 41 percent in the 11- to 20-year 
age class to 55 percent in the 51- to 60- and 61- to 
70-year classes, then declining in the older age classes. 
F-A41779 
Figure 29.—This loblolly pine stand is about 60 percent 
stocked, or 10 percent better than the average pine stand 
in the Coastal Plain. 
In the northern Piedmont, average stocking in the 
upland hardwood type was only 49 percent, while in 
the shortleaf pine-hardwood type of the southern Pied- 
mont it was 61 percent. For the Piedmont as a whole 
in all cordwood and saw-timber stands, pine types 
averaged 47 percent stocking, hardwood types 51 
percent. 
21 
