2 BULLETIN 820, U. S. DEPARTMENT OF AGRICULTURE, 
and prolong the tenure of jack pine over extensive-areas of sandy 
ridges and plains. There are large areas with poor soil and severe 
climate, especially in Canada, on which jack pine is the permanent 
forest growth. It is, therefore, one of the characteristic forest types 
of the North.1 
In the Lake States jack pine produces chiefly small-sized, knotty 
lumber, much inferior to that from the Norway and white pines which 
grow withit. it has, however, good possibilities of profitable utiliza- 
tion for pulpwood, box boards, mine timbers, and other low-grade 
material, its rapid growth when young, its good yields per acre on 
poor land, and the ease which it reproduces itself make it suitable 
for timber growing on a short rotation. | 
Jack pine is an important tree for forest management on poor, sandy 
soils in the region of its natural distribution, and has been successfully 
planted outside of its natural range in the sand hills of western Ne- 
braska. In the Lake States there are hundreds of thousands of acres 
of poor, sandy plaims-land, impoverished by fires, on which jack 
pine is a pioneer tree, forming stands by natural reproduction where 
white and Norway pine have not appeared. These two species come 
in later with improved soi! conditions and under the shelter of the 
jack pine. Wherever good stands of jack pine can be secured without 
expense by natural reproduction, that is usually preferable to plant- 
ing the land with more valuable species at considerable expense and 
with less certainty of success. 
DISTINGUISHING CHARACTERISTICS. 
Jack pine has leaves in bundles of two, from ? to 12 inches long, flat, 
or slightly concave on their inner surface, and surrounded by a short 
sheath. The cones are frem 14 to 2 inches long, oblique at the base, 
sessile, erect, and strongly incurved, with thick, soft scales, armed with 
minute, incurved prickles which usually fall away. (See Pls. I and II.) 
The only other two-leaved pine with which jack pine is likely to be 
confused is the lodgepole (Pinus contorta). The ranges of these two 
species overlap slightly in central western Alberta.? Their leaves are 
about the same size, and theirconesareverysimilar. Thecones of both 
are curved, but those of jack pine are erect or pointing in the direction 
of the end of the twig, while those of lodgepole are horizontal or declin- 
ing, pointing upward or even backward. Jack pine is further dis- 
1The growth, yield, form, and volume tables which are the chief basis for this bulletin were compiled 
mostly from measyrements taken in 1905 on pure, dense, even-aged stands of jack pine in Hubbard 
Coutity, Minn., by Prof. H. H. Chapman, of the Yale Forest School. The bibliography of data used and 
reports consulted in the preparation of this bulletin is found on page 34 (appendix). 
2“<The lodgepole is ordinarily confined to higher elevations in Alberta. The upper portions of river 
slopes will be occupied by lodgepole pine, while the lower slopes and bottom lands may be covered with pure 
jack pine. As the river is followed into the hills the lodgepole pine gradually replaces the jack pine on the 
lower levels and finally occupies the whole river bottom and side slopes.” —Extract from a letter by R. H. 
Campbell, Director of the Canadian Forestry Branch. 
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