210 NINETEENTH REPORT. 



Probably the most obvious characteristic of the forest vegetation as a 

 whole is the extreme variety of species composing many of the associa- 

 tions and the general dissimilarity between it and the usual upland type 

 lying westward and mostly outside of the county. One may clearly 

 observe this transition in going from Ann Arbor to Detroit. The change 

 is abrupt and takes place a short distance west of Ypsilanti or some 

 twenty miles west of the Detroit River, where tlie rolling morainal 

 topograpliy changes to the level glacial lake basin of which Wayne 

 Coimty, except the small northwest portion, is a part. The change is 

 apparent in the shrubs and lierbs, but particularly in the trees that now 

 remain either scattered or grouped in woodlots. Many of the trees show 

 by their age tliat they were part of the heavy and nearly unbroken 

 forest which existed less than a century ago. People who remember tlie 

 forest as it existed fifty years ago testify that there was an abundance 

 of such trees as black walnut, whitewood ( Lirodendron Tulipifera) and 

 others which would have made the individuality of the forest more 

 strongly marked then than at present. This type of vegetation covers 

 a large and important part of southeast Michigan along that portion 

 of the state bordering the St. Clair River, Lake St. Clair, the Detroit 

 River, and Lake Erie. It occupies the glacial lake basin following the 

 trend of the ancient beach lines in its western limits. Unpublished obser- 

 vations by Schaffner, Transeau, Sears, and others, make it evident that a 

 similar distinction exists over this glacial lake basin which extends south- 

 ward and eastward over northern Ohio, bordering Lake Erie. In a survey 

 of the vegetation made by automobile they were enabled to mark the 

 change of vegetation wherever they passed upon the basin area. Over 

 the western morainal area, such as we observe about Ann Arbor, the 

 hard maple and beech, in order of relative abundance, are characteristic 

 trees. This is the climax "forest, as recently given by Zon for this region. 

 Over the eastward lake basin area occur a variety of associations, but 

 we notice a marked absence of the hard maple-beech forest, except for 

 a small area here and there, as in southeast Brownstown. Beech often 

 occurs but, except for the small Plymouth-Northville district, it is asso- 

 ciated with Acer ruhrum, A. saccharinum, and other trees, forming a 

 forest totally unlike that outside the basin, botli in character and appear- 

 ance. 



CHARACTERISTIC TREES. 



The great variety of species occurring in several of the forest associa- 

 tions of Wayne County makes it difficult, at the outset, both to recognize 

 some of the associations, particularly in the central north-to-south belt, 

 and to follow the boundaries formed by the meeting of two associations, 



