TORREYA 
February, 1012 
Vol. 12 No. 2 
WINTER-KILLING AND SMELTER-INJURY IN THE 
FORESTS OF MONTANA* 
By GEORGE GRANT HEDGCOCK 
The great Washoe smelter at Anaconda, Montana, among the 
largest in the world, throws off annually, in spite of certain pre- 
cautions taken to prevent it, a great volume of sulfur oxides and 
arsenic. There is little doubt, in view of the experiments made 
with sulfur dioxid, most of which have been made by European 
investigators, that this form of sulfur even when very dilutely 
diffused in air is injurious to plants. The fumes of arsenic 
take on a solid condition in open air and are probably not injuri- 
ous to the foliage of forest trees. The effect of the accumulation 
of sulfuric acid and arsenic in the soil on the roots of plants is 
still somewhat uncertain, especially in small quantities. An 
excess, especially of the former, must undoubtedly interfere with 
the natural processes of decomposition and soil fertilization. 
The latter in large quantities can hardly fail to be poisonous. 
During the winter of 1908-9 in some portions of the North- 
west, more especially in Montana, many forest trees suffered 
from a peculiar form of injury which was apparently due to 
weather conditions the probable cause of which will be discussed 
in another paper. This injury was most severe in the following 
national forests: Absaroka, Beartooth, Bitterroot, Blackfeet, 
Deerlodge, Gallatin, Madison, and Jefferson. The injury was 
frequently quite severe. During the past three years, in all, 
about 40,000 acres of coniferous trees have died from its effects 
in Montana. 
This form of winter injury has received the name locally of 
* Published by permission of the Secretary of Agriculture. 
[No. 1, Vol. 12, comprising pp. 1-24 was issued 22 Ja. 1912.] 
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