29 
4. Picea Engelmanni (Parry) Eng. (Engelmann's spruce). 
5. Pinus ponderosa Laws. (western yellow pine). 
6. Pinus flexilis James (limber pine). 
7. Juniperus scopulorum Sarg. (Rocky Mountain juniper). 
8. Juniperus communis L. (dwarf juniper). 
The last three named species are quite resistant and in Deer- 
lodge National Forest in the Smelter Zone show little or essen- 
tially no injury from smelter fumes. 
The ability of trees to withstand the Red Belt form of injury 
is not in the same ratio as that of thcir resistance to smelter 
fumes. In order of the susceptibility to winter injury the 
species above named are as follows: 
. Pinus ponderosa. 
. Pseudotsuga taxifolia. 
. Pinus contorta. 
Pinus flexilis. 
Picea Engelmanni. 
Abies lasiocarpa. 
. Juniperus scopulorum. 
Juniperus communis. 
All species showed some injury in the Red Belt winter injury 
of 1908-9. Pinus flexilis, Juniperus scopulorum, and J. commu- 
nis exhibited, so plainly, forms of injury that the health of these 
species in the portions of the Smelter Zone where they are found 
is taken as proof that no winter injury has occurred in these 
regions during recent years. 
The leaves of aspens (Populus tremuloides Michx.), alders 
(Alnus tenuifolia Nutt.), and of willows (Salix spp.) exhibit 
peculiar forms of leaf scorch, blackened, reddened, or discolored 
areas of parenchyma which are not found on leaves of the same 
species in other regions, in adjacent forests subjected to the Red 
Belt winter injury, but not to smelter fumes. 
In much of the inner portion of the Smelter Zone adjacent to 
the smelter, few or no seed are borne by conifers, and little or no 
reproduction is taking place. The seedlings, apparently, are 
killed as soon as they appear above the ground. Not so in areas 
outside of the Smelter Zone, where only winter injury has 
Ll 
QU Uo» 
