INTRODUCTION 
In his classic article on the climax forest of 
Isle Royale, Lake Superior, Cooper (5) refers to the trans- 
itional zone between the two great phytogeographic regions - 
the northeastern conifer forest and the eastern deciduous 
forest. Certain features of both regions, he says, are 
found in the southwestern portion of the island; but he 
did not carry out his first intention of tracing the relat¬ 
ions between them. On the mainland of Michigan to the south, 
the maple forest is well developed, especially at certain 
inland points. Areas near the coast, however, may show 
many transitional features, such as occur in the Porcupine 
Mountains, which are about 125 km. south southwest of Isle 
Royale. These so-called mountains, which are really 
prominent hills or hilly ridges, represent the highest points 
of land reached in the Upper Peninsula. As Leverett (20) 
points out, they are "the most conspicuous features in this 
entire area, for they rise on their north slope very abruptly 
from the shore of Lake Superior to a height of 1400 feet 
above the lake". 
The purpose of this ecological survey was to make 
a careful study of the climax formation of the region, in 
eluding their relations to each other, and to correlate, 
if possible, the various plant associations occurring within 
them. 
