32 
BULLETIN 933, U. S. DEPARTMENT OE AGEICTTLTUEE. 
for this prevailing inferiority of walnut plantations — either there 
was a poor choice of planting sites or there was wrong management 
of the planted stands, or both. 
Table 13. — Diameter growth in plantations, in comparison with average and 
slow grotvth in natural stands. 
Age 
(years). 
Diameter, breast high (inches). 
In plan- 
tations. 
In natural stands — 
Of aver- 
age 
growth. 
Of slow 
growth . 
10 
20 
30 
40 
50 
60 
70 
80 
2.0 
5.2 
7.4 
9.2 
10.9 
12.3 
13.4 
14.4 
1.2 
5.0 
8.8 
12.5 
15.7 
18.3 
20.6 
22.2 
0.6 
3.1 
5.4 
8.0 
10.8 
12.9 
15-2 
17.2 
CHOICE OF PLANTING SITES. 
The plantations of walnut in the prairie regions were quite natu- 
rally started in the situations in which the owners most needed trees ; 
that is, on the treeless uplands or, occasionally, in recent years, on 
parts of cleared bottom lands. The sites selected were only rarely 
those which supported tree growth at the time of the settlement. 
The soil quality of these sites may be excellent, but the moisture 
present in the soil during the summer is insufficient for the flourish- 
ing growth of walnut. 
As has been pointed out on pages 4 and 18, walnut needs for good 
growth a deep, fertile soil, both well watered and well drained, per- 
mitting the free movement of soil moisture and, at the same time, the 
access of air to the roots. These qualities are the more necessary the 
less favorable the climatic conditions, especially the precipitation. 
From Indiana westward soils suitable for planting are to be found 
j^rincipally in bottom lands, but bottom-land soils are in fact to be pre- 
ferred even in the East. Swampy areas and places where cottonwood, 
willows, sycamore, or river birch form, or have formed, the chief 
growth will usually prove unsuited to walnut, though areas subject 
to floods for short periods, in which the backwater does not stand 
long in the depression, may form excellent sites. If the soil is a 
sterile sand, or if hardpan exists not far beneath the surface, as in 
parts of the Lake States, walnut can not be grown satisfactorily, 
even in the most favorable climate. 
In the East, with its larger amount and better distribution of rain- 
I'all. much more freedom in the selection of planting sites is possible 
than in the prairie regions or in the Lake States. In the limestone 
regions of Tennessee, Kentucky. West Virginia, and the northeastern 
part of the range in general, cut-over lands and even rocky hillsides, 
