FOREST FORMATIONS AND FOREST TREES 



47 



ago, gives descriptions of a part of the arborescent flora of the state. 

 Unfortunately there is no new work which gives all of the trees nor one 

 which discusses the forest formations. Probably the most useful single 

 book is the new work of Dr. Britton. 1 Anyone interested in the larger 

 aspects of forestry will find useful articles from time to time in the 

 National Geographic Magazine and in the magazine, Conservation. 



Fig. 42. — Sub-alpine Scrub at Timbebline 



This latter publication is the organ of the American Forestry Association. 

 The Flora of Colo ado 2 is valuable for the professional botanist — indeed 

 it is -a perfect mine of information — but is rather too technical in its 

 treatment for the amateur. The present writer has made free use of 

 this work in the preparation of his account of the tree species of Colorado. 

 At the close of the present paper are noted some of the books and 



1 Britton, N. L., North American Trees, pp. 1-894, New York, 1908. 



3 Rydeerg, P. A., Flora of Colorado, Bull. 100, Colo. Agric. Exper. Sta., pp. 1-447, Ft. Collins, 



:oo6. 



