FOREST FORMATIONS AND FOREST TREES 



39 



away at the sides, these river-bottom forests may be a quarter or half- 

 mile in width. More often, however, they are much narrower. Along 

 the smaller streams there is frequently a single row of cottonwoods or 

 willows. The pine-ridge forests are on the high ground extending 

 between adjacent streams where they grow in coarse, frequently rocky 

 soil. Good examples of pine-ridge forests are seen along the divide 

 between the South Platte and the Arkansas and also at the edge of the 



Fig. 36. — Map of Colorado. The continental divide is shown by the heavy dotted 

 line, the front range of foothills by the short horizontal lines. East of the foothills lie the 

 great plains. 



"high plains" in the northeastern part of the state. The trees of these 

 ridges are rock pines and cedars which form scattered groups hardly to 

 be dignified by the name of forest. Near Pawnee Buttes in. northeastern 

 Colorado there are limber pines instead of rock pines. To the south, 

 and in certain parts of the western area of the state, the pinyon pine is 

 added to the rock pine and cedar. - 



Classification of forests. — From a botanical standpoint forests may 



