14 BULLETIN 149 7, U. S. DEPARTMENT OF AGRICULTURE" 
this disease are taken promptly the risk of loss is small. _ White 
spruce is subject to losses due to the spruce budworm, especially in 
the natural stands where balsam fir is usually associated with the 
spruce: but in plantations where the spruce is planted pure or in 
mixture with pine, losses are not likely to be serious. Tamarack and 
European larch are both subject to attack by the larch sawfTy. The 
danger of destruction by this pest is so great that for this reason 
alone planting of tamarack in the swamps can not be recommended. 
It may be that either species if planted on upland sites, where both 
make Vigorous growth, would be able to resist successfully the at- 
tacks of the insect, although even this is not certain. Jack pine is 
attacked by several insects and a fungous disease, but so far none of 
these has proved to be serious. Other species, as sugar maple, bass- 
wood, red oak, white ash. eastern cottonwood, and northern white 
cedar, are not subject to damage to a degree that should affect their 
desirability for planting. 
DOUBTFUL SPECIES 
Several of the species that have been mentioned have certain 
obvious advantages but yet are not recommended for planting, either 
because too little is known as to their probable success in the northern 
Lake States or because existing plantations are not or do not promise 
to be satisfactory. These are Scotch pine, Norway spruce, eastern 
cottonwood, white and green ash, Russian poplar, and box elder. 
Scotch pine has been extensively planted in the region. It adapts 
itself readily to a wide variety of soils including the poorest. The 
trees in the older plantings, however, are almost invariably so 
crooked and have such large, heavy limbs that it is doubtful whether 
they will be valuable for anything but cordwood. For that purpose 
Scotch pine is less desirable than jack pine, which grows faster 
and in addition to cordwood will produce lumber which is not 
excessively knotty. It is often stated that Scotch pine from seed 
produced in northern Russia (known as the Riga variety) or in 
the northern Scandinavian countries will grow straight and clean. 
If Scotch pine is to be planted, an attempt should be made to obtain 
seed or stock from these sources. It is probable also that the form 
of the trees could be improved by planting them not more than 3 or 
4 feet apart. On the whole, however. Scotch pine can not now be 
recommended for planting in the northern Great Lakes region. 
Norway spruce has also been planted in several parts of the region 
but has been only moderately successful. Usually only a few trees 
grow rapidly. It certainly has not done as well as. according to 
report, ft has done in the southern part of the Lake States or in 
the Northeastern States, where its rapid growth and ease of propa- 
gation have sometimes given it the preference over the native spruces. 
The evidence from plantations in the northern lake States is not 
sufficient either to condemn Norway spruce or to prove that it is 
either inferior or superior to white spruce. Natural growth of 
white spruce does so well in the region, however, that it is recom- 
mended in preference to Norway spruce. 
Cottonwood plantations were not found in the region studied, 
although many have been established in the prairie region to the 
west and south. Cottonwood planting and the yields from planta- 
