6 BULLETIN 820, U. S. DEPARTMENT OF AGRICULTURE, 
NORWAY PINE LAND. 
Jack pine is found in mixture with Norway pine on fresh-to-dry 
flats and ridges of fine sand, jack pine sometimes composing one-half 
the stand. 
WHITE PINE LAND. 
On moist flats of very fine sand and silt, where white pine thrives, 
jack pine occurs sporadically as a subordinate tree. After lumbering 
and burning on these lands, however, jack pine may take possession 
and for a while form the dominant growth. 
JACK PINE AND POPLAR (ASPEN). 
Considerable areas bearing jack pine and poplar (aspen) are found 
in the western part of the range of jack pine in Canada. The type 
varies “‘from jack pine scattered in poplar to poplar scattered in jack 
pine. In these areas the jack pine is usually of very good growth, 
since it occupies better soils than it usually does.’ 
CONIFEROUS SWAMPS AND MUSEEGS. 
In the Lake States jack pine grows only occasionally in swamps, 
but toward the north, as the number of tree species inhabiting 
muskegs gradually decreases, the proportion of jack pine in them 
becomes larger. However, in this type the jack pine is seldom of 
commercial importance. 
Tables 29, 30, and 31 (appendix) show what species occur, more or 
less abundantly, with jack pine in the Lake States and in Canada on 
land where it is the prevailing tree. The appearance of tamarack 
and ash in Table 29 indicates that the edge of a swamp was included 
in some of the acres measured, as these species are not found in any 
of the jack-pine forest types. 
SOIL, MOISTURE, AND LIGHT REQUIREMENTS. 
Jack pine is primarily a tree of light, dry, medium to coarse, 
thoroughly drained sands and gravels. It is confined to geological 
formations which contain no limestone.? One ofits important char- 
acteristics is its ability to reproduce and grow fairly well on thin, dry, 
sandy uplands where other species will not grow. Jack pine grows 
best, however, on fairly deep upland flats, where the drainage is good 
but the water table fairly near the surface. This is really Norway — 
pine land, from which Norway pine usually crowds out the jack pine 
if fires are kept out.? (See Pls. V, VI, and VII.) 
1 Extract from aletter by R. H. Campbell, Director ofthe Canadian Forestry Branch. 
2 See B. Moore in Vol. XVII, p. 887, of the Journal of Forestry. 
3 Table 17 (appendix) indicates that in northern Minnesota jack pine stands occur prevailingly on me- 
dium to coarse sands, Norway pine stands on fine sand, and white pine stands on very fine sands and silts. 
(Medium to coarse sands comprise in a large degree the ‘‘Soils of the Laurentian country in Canada, where 
jack pine reaches its best development.’’ See Forestry Quarterly, Vol. IX, No. 1, p, 7.) 
