MISTLETOE INJURY TO CONIFERS. 9 
or in some cases the entire tree may succumb (fig. 7 and PI. ITI, fig. 
1.) In many parts of the Whitman National Forest, wherever the 
heaviest infection of yellow pine occurs the percentage of dead or 
spiketopped trees reaches a comparatively high figure. 
In a report to Supervisor Ireland, Ranger Smith, in referring to 
the seriousness of the infection of yellow pine in the vicinity of 
Susanville, Whitman National Forest, states that since 1907, the 
year in which the mistletoe damage in the region first received at- 
tention, the infection 
of all age classes has 
been growing worse, 
probably 40 per cent 
of the stand now be- 
ing infected. Of the 
more mature stand, 
approximately twice 
as many trees near 
the station as were 
noted in 1907 have 
since died. Ranger 
Smith further states 
that for a most pro- 
nounced general in- 
fection of all species 
the drainage basin of 
the South Burnt 
River particularly 
illustrates the devas- 
tating effects of mis- 
tletoes. “Almost 
every yellow pine 
from seedlings up 
and Douglas fir above Fie. 6.—Douglas fir, showing the death of the upper por- 
sapling size 1s heavily tion of the crown caused by Razoumofskya douglasii. 
3 The tree to the right with the series of immense brooms 
infected and most of also has a dead top. A large broom had split off from 
the mature timber the trunk of the tree on the left. All the young growth 
in the vicinity of these trees is seriously infected. 
shows great retarda- 
tion of growth and is now adding little or no increment. This 
infection covers a large part of the best yellow-pine sites in the 
yellow-pine belt of this watershed.” This region was not visited by 
the writer, but to judge from studies in other parts of the same 
forest Ranger Smith’s observations are undoubtedly correct. 
In order to determine the relative amounts of different species 
cut as snags on the W. H. Eccles Lumber Co. sale (Whitman Na- 
24182°—Bull. 360—16 
9 
