12 BULLETIN 316, U. S. DEPARTMENT OF AGRICULTURE. 
Table 1. — Average height of willow stands in the Mississippi Valley. 
Stand near- 
Stand. 
Soil. 
Average 
height. 
Clay City, Ind 
Ste. Genevieve, Mo 
Cairo, 111 
Memphis, Tenn 
Helena, Ark 
Vicksburg, Miss 
St. Joseph, La 
Williamsport, La... 
Years. 
53 
40 
42 
37 
55 
41 
45 
57 
Close. . . . 
Medium. 
Close. . . . 
Medium. 
Close. . . . 
...do 
...do 
...do 
Sandy 
do 
do 
Very poor drainage. 
Black 
do 
.....do 
do 
Feet. 
82 
74 
83 
81 
110 
98 
116 
104 
In the South black willow attains its principal height growth at 
from 35 to 40 years; in the North at from 30 to 35 years. In the 
South, however, growth frequently continues more slowly after this 
age until the heights ranging between 100 and 135 feet are reached. 
Table 2 gives the average height growth of black willow, based on 
255 trees in the Mississippi Valley region from southern Indiana and 
southern Missouri to central Louisiana. Most of these measurements 
were taken in the southern half of this range. 
Table 2. — Height growth of black willow in the Mississippi Valley. 
(Based on 255 trees.) 
Growth 
Periodic 
Growth 
Periodic 
Age. 
Height. 
in 5-year 
annual 
Age. 
Height. 
in 5-year 
annual 
periods. 
growth. 
periods. 
growth. 
Years. 
Feet. 
Feet. 
Feet. 
Years. 
Feet. 
Feet. 
Feet. 
5 
32 
^2 
6.4 
35 
96 
7 
1.4 
10 
50 
18 
3.6 
40 
101 
5 
1.0 
15 
63 
13 
2.6 
45 
105 
4 
.8 
20 
73 
10 
2.0 
50 
109 
4 
.8 
25 
82 
9 
1.8 
55 
113 
• 4 
.8 
30 
89 
7 
1.4 
60 
116 
3 
.6 
DIAMETER GROWTH. 
Black willow makes its most rapid diameter growth during the 
first 10 years, after which the growth falls off gradually. At the age 
of 60 years the average tree is generally mature or overmature, and 
produces little increment after that. Occasionally an individual will 
survive longer than this in a protected place and continue growing 
up to an age of 75 years. On poor sites, such as a rather sandy 
river bank, or on soils having a scant moisture supply, the diameter 
growth is about 0.4 of an inch per year for the first 10 years, while 
on the best sites in the South, where there is a long growing season, 
it averages from 0.5 to 0.7 of an inch. The maximum annual diame- 
ter growth on the best sites is 0.9 of an inch the first 10 years. A 
particularly interesting fact is noted in that beyond the age of 45 
years the annual diameter growth of all trees is practically the same, 
averaging about 0.28 of an inch. The trees having a maximum 
