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ROP ee ee ne ee Be ee, ee Mie esr EL 7) eS a a le Eee aes eS ey Ne Te ey tS Fp, SES = ae tal Re ee ee er 
1913] COOPER—ISLE ROYALE 13 
having been least disturbed by accidental conditions such as fires; 
and of these islands Smithwick was the most iently situated. 
So primeval and luxuriant is the aspect of the forest here that at 
first it seemed almost safe to assume that the island had never been 
burned over since its emergence from the lake. [I found, however, 
in one place, at a depth of one-third of a meter, a layer of carbona- 
ceous material with fragments of charcoal. It is certain then that 
fire, to an unknown extent, has entered into the history of the 
island, notwithstanding the many indications to the contrary. 
Nevertheless, granting that the island may have been burned over 
at some time, it is plain that the forest has long since returned to 
its natural condition and may fairly be taken as a suitable area 
for the study of the climax state. We may be sure that the forest 
on Smithwick Island has not been disturbed for many hundreds 
of years at least, and this is not often the case on ‘the main Isle 
Royale. 
There is one somewhat abnormal feature of the conditions 
surrounding these outer islands that should be mentioned, namely, 
that the exposure to the strong lake winds is greater than on the 
main island, and that the death-rate among the trees is thereby 
increased, and not always proportionally among the different 
species. On the whole, though, this added exposure merely inten- 
sifies certain processes that are in operation everywhere, and thus 
renders them easier of observation. 
‘The average elevation of Smithwick Island is about 7m. The 
southwest one-third was thoroughly burned over about 15 years 
ago. The forest covers the unburned portion almost completely, 
being bordered along most of the Rock Harbor side by a narrow 
shingle beach, and on the lakeward edge by a belt of bare sloping 
rocks, frequently interrupted by broken or precipitous sea cliffs. 
Seen from Rock Harbor the forest has the following appearance, 
and this description will apply fairly well to the climax forest of 
Isle Royale in general (fig. 2). The first impression is of great 
density, the thick foliage extending to the ground at the edge of the 
forest, allowing no view into the interior. The sky line is ragged, 
made up of an irregular combination of sharp points and rounded 
curves, due to the mixture of broad-leaved trees and conifers. 
