FOEEST PLANTING IN THE LAKE STATES 
53 
The plantations of white spruce are not old enough to give infor- 
mation on yield, but Kenety (4.0) , after making a study of the species 
in Minnesota, concluded mat in plantations " 50 cords per acre is 
a probable yield at the end of 50 years on the proper type of soil." 
In a commercial planting operation with white spruce in Quebec 
(44) a yield of 38 cords in 50 years was predicted from a study of 
natural stands. 
These figures derived from the growth of natural stands may be 
regarded as conservative, for the regular spacing between the trees 
in plantations should promote a more rapid and uniform develop- 
ment of a greater number of trees in the stand and hence a higher 
yield than would be possible in the more or less irregular natural 
stands. 
.Representative yields at merchantable size and age have been esti- 
mated for plantations on medium sites, and it is believed that they are 
conservative for the region. Jack pine should produce on the average 
30 cords of pulpwood to the acre at 40 years when the trees average 
about 5 inches in diameter. Norway and northern white pine will 
probably require 60 years to produce small saw timber. The yield 
at 60 years should be at least 15,000 and often 20,000 board feet to the 
acre. At 60 years the trees would average 9 to 10 inches in diameter 
with a fair proportion of larger trees up to 18 inches. Indications 
of the yields of the pines at different ages on different sites are given 
in Tables 7, 8, and 9. a White spruce may be expected to produce 30 
cords of pulpwood in 60 years. These ages are as low as they can be 
placed with any degree of assurance, although under especially favor- 
able conditions it may be possible to grow merchantable crops of 
these species in shorter periods. The yield of any specific plantation 
should be estimated for the particular conditions of the planting site. 
Table 7. — Yields of Norway pine in naiural well-stocked stands 
Age (years) 
Total 
height of 
average 
tree on 
medium 
site 
Diameter breast 
high on medium 
site 
Yield per acre by site quality 
Average 
Maximum 
Good 
Medium 
Poor 
5 
Feet 
2 
20 
30 
40 
50 
58 
65 
72 
78 
83 
92 
Inches 
Inches 
Board feet 
Board feet 
Board feet 
10 
1 
3 
5 
7 
9 
10 
12 
13 
14 
15 
17 
2 
6 
10 
13 
16 
18 
19 
21 
22 
23 
25 
20 
30 
40 
4,100 
9,400 
15, 100 
20, 900 
26, 500 
32, 300 
38,500 
50, 800 
2,000 
6,100 
10,200 
14, 300 
18,600 
22, 900 
27,400 
36, 700 
50 
2,800 
60 .... 
5,300 
70 
7,900 
80 
10, 700 
90 
100 
13,700 
16,900 
120 
23,100 
Figures in this table are taken or adapted from the publication by Woolsey and Chapman (77) en Norway 
pine in this region. Board foot yields by Seribner rule. 
9 These tables, based on data from natural stands for different sites, soils, localities, 
and degrees of utilization, are not comparable one with another and are only suggestive 
of the yields of plantations. Their use should be checked on any specific area on which 
yields are to be estimated. 
