216 TWENTY-FIRST REPORT. 



THE UPLAND VEGETATION OF LAKE COUNTY, MICHIGAN. 



TJie Deciduous Forest Climatic Formation. 

 I. The Regional Climax Association Type. 



The Climax Forest Mixed Hardwood Association. 

 II. The Bdaphic Formation — Complexes of the Region. 



a. The Yellow-White Pine Complex. 



b. The Black-White Oak Complex. 



1. The Jack Pine Association Complex. 



2. The Jack Pine-Oak Association Complex. 



3. The Black-White Oak Association Complex. 



It is thus contended upon ecological grountls that any region should be 

 classified upon the basis of the highest ecological type which may find expres- 

 sion therein. Upon this basis the southern peninsula should then be consid- 

 ered as a northern extension of the deciduous climax forest formation. This 

 classification also establishes the existence of edaphic formations — two of these 

 are here recognized, viz. : the yellow-white pine and the black-white oak for- 

 mations. Further field work may make it seem desirable to include the jack- 

 pine association in the same category. At the present time, however, it has 

 seemed best to include it as the initial stage in the black- white oak complex. 



Nichols ('17, '18) has reached similar conclusions relative to the edaphic 

 formation complex on the basis of his work in Cape Breton, but his inferences 

 rest mainly upon field observations. In 1910 I expressed a similar conclusion 

 before this section relative to the oak formation of south central Michigan. 

 It would seem that we now have in the above data adequate experimental 

 demonstration of the regional edaphic formation, which under natural condi- 

 tions will remain definitely self-perpetuating and successfully maintain itself 

 against a successional invasion of the regional climax association, the mixed 

 hardwood association. If these conclusions are substantiated by further field 

 and experimental results, it is obvious that we must reconstruct our concep- 

 tions as to succesion and the ultimate domination of a regional climax forma- 

 tion within the geographical limits of extensive transitional zones. 



Western State Normal School. 



Kalamazoo, Mich. 



