250 THE STUDY OF PLANT COMMUNITIES ' Chapter X 



not extend to the northwest limits of the deciduous formation. 

 Beech is replaced in the climax by basswood (Tilia americana), 

 beginning in Wisconsin and continuing into Minnesota. 95 Other- 

 wise the community is changed very little. 



Hemlock-Hardwoods Association — between the northern con- 

 iferous forest and the deciduous forest lies a transitional association 



&.L2 



FlG. 122. Virgin hemlock (Tsuga canadensis) as it once occurred in the 

 hemlock-hardwoods association of the northeast and in mountain coves 

 southward.— U. S. Forest Service. 



of which hemlock (Tsuga canadensis) is an important and con- 

 stant member, together with beech and sugar maple, and, in lesser 

 numbers, yellow birch (Betida Intea), white pine, basswood, elm, 

 white ash (Fraxinus americana), red oak, and other species. The 

 association, which extends from northwestern Minnesota through 

 the Lake States to Nova Scotia, has been given various names by 

 authorities with different points of view. It is the area throughout 

 which occurred the magnificent pine forests of the recent past— 



