G4 RURAL MICHIGAN 



on the driest and poorest sandy gravels, the red pine 

 [Pinus resinosa) associates and sometimes predomi- 

 nates, the white pine not representing more than ten 

 to twenty per cent of the number of trees. In the 

 ]iortliern regions jack pine (Pinus divaricata) takes 

 the place of the red pine. The typical pine forest 

 on fresh sandy soils consists of wliite pine (-iS to 55 

 per cent of the dominant growth) mixed with red 

 pine (25 to 45 per cent) with scattering hemlock 

 (10 to 15 per cent) and occasional fir and hard- 

 woods. On moister sand with loam or clay subsoil 

 hemlock and hardwoods replace the pine, the red 

 pine vanishing entirely and the white pine occurring 

 only in large isolated individuals. Into wet or 

 swampy places the white pine also penetrates in 

 single individuals among arbor vita?, hackmatack, 

 and spruce. As the loam in the composition of the 

 soil increases, the hardwoods increase numerically, 

 the white pine occurring only in single individuals 

 and groups, and red pine and hemlock only occa- 

 sionally. Finally, the heavy clay soils toward the 

 southern range of the species give absolute preponder- 

 ance or exclusive possession to the hardwoods, mainly 

 sugar maple, yellow birch, and beech, although oc- 

 casionally white pine appears scattered, or even in 

 smaller or larger groups." ^ 



Of particular areas a number of special studies 

 have been carried on to ascertain the character and 

 correlation of the flora, fauna and physical condi- 



^ Spalding and Fernow: "The Wliite Pine," Washington, 

 189!), 14; map facing p. 11. 



