506 MINNESOTA STATE HORTICULTURAL SOCIETY, 
growth is much slower; so at the end of thirty years we will begin to cut 
100 acres a year, and will continue to seed or re-seed the same amount of 
land. The mill has now been placed on a permanent basis and may continue 
operations indefinitely, occupying only 3,000 acres of land with growing 
pulp material. 
The figures given for the Hendrickson trees should not be accepted as 
conclusive for all cases, as the rate of growth varies with conditions. In 
the case of the black spruce cut in the woods at Cloquet, there was an in- 
crease of diameter during the last ten years equal to about one-third of the 
previous growth in diameter. This one-third growth in diameter for the 
ten years represents a sectional area almost as great as that of the whole 
fifty-five years previous. The sectional area of the stem with diameter 
of 334 inches is 8.93 square inches; with a diameter of 2% inches grown in 
fifty-five years it was 4.9 square inches. The difference between these two 
areas is 4.03 square inches; which is the sectional area grown during the 
last ten years. This increased growth was due, no doubt, to the removal 
of surrounding timber trees, which over-topped and suppressed young 
growth below. 
The great diffe-ence in rate of growth of the Norway and the native 
Minnesota spruces is more clearly shown in the following summary: 
Black, spruce in woods at Cloquet, one inch in 19.26 years for 65 years. 
Black spruce in stock pile. Cloquet, one inch in 11.60 years for 52.92 
years. 
White spruce in stock pile, Cloquet, one inch in 8.35 years for 79.30 
years. 
White spruce in Bulletin 49, one inch in 7.50 years for 50.67 years. 
Norway spruce, Experiment Farm, one inch in 3.30 years for 15 years. 
Norway spruce, Hendrickson Farm, one inch in 2.20 years for 30 years. 
Norway spruce, Parker Farm, one inch in 2.30 years for 30 years. 
Norway spruce, Rosehill Nursery, one inch in 2.14 years for 25 years. 
Whether or not the wood of the Norway spruce is as well adapted to 
pulp making as the black spruce, I cannot say, but will make that the sub- 
ject of further investigation. It is a heavier wood than either the white 
or the black spruce, with a specific gravity of .47 as compared with .4051 
and .458 in the others. The black spruce is a short lived tree on dry land 
in Minnesota, so that when we find Norway spruce growing to a timber size 
in thirty years, around a well drained open field, with sandy subsoil, we may 
assume that it has some advantage over black spruce, which is general in 
muskegs and other wet places. 
* To compare Norway spruce with the red spruce of Maine, which is the 
great pulp wood of the eastern states, I obtained from the Third Annual 
Report of the Forest Commissioner of the State of Maine (1896), figures 
showing that in 106 trees 108 years old there were 1,229 cubic feet, an average 
of 11.6 cubic feet for each tree. And for pine, which he proposes to substi- 
tute for spruce as pulp material when the latter is exhausted, 121 trees con- 
tained 1,030 cubic feet at an age of fifty-four years, or 8.5 cubic feet per 
tree. The average for the Norway spruce on the Hendrickson place is 
13.15 cubic feet at thirty years, and, supposing that the Maine figures exclude 
the bark I will deduct one-sixth, which is the allowance made by the Maine 
commissioner for bark, leaving 10.96 cubic feet for a thirty years’ growth. 
This. as you notice, is greater than the volume for pine at fifty-four years, 
