990 JOURXAI, OF FORESTRY 



was only refused on 25,555 hectares out of a total of 177,090 ! 



Foresters interested in the administration of public forests (as well 

 as the teacher) will do well to study Marc's excellent notes. 



T. S. W., Jr. 



The Ecological Relations of Roots. By John E. Weaver, Carnegie 

 Institute of Washington. Publication 286. Pp. I-VII and 1-228, with 

 58 figures and 23 plates, three of which are in colors. 1919. 



It is only in recent years that American botanists and foresters have 

 given serious attention to the study of root habit and root systems. 

 The labor involved in excavating and tracing root systems to the 

 depth in some instances of ten or more feet and the difficulties met with 

 in following delicate roots through the soil and sub-soil has deterred 

 investigators from attempting work in this fruitful field. For many 

 years, however, students of silviculture have recognized the need for 

 more and better information on the root habit of trees in order better 

 to correlate forest vegetation with the site factors. More recently plant 

 ecologists have appreciated the need of investigation in this field, and 

 the light which careful work therein is likely to throw on a number of 

 unsettled problems in plant distribution. 



More than twenty-five years ago Kefifer, working for the Division of 

 Forestry in the United States Department of Agriculture, traced the 

 root system of a number of tree species, growing in the Dakotas and 

 elsewhere in the West. More recently Cameron and Markle have 

 studied the root systems of desert plants and Sampson has studied the 

 root systems of range plants. Some fifteen years ago the writer of this 

 review studied the initial root habit of some one hundred and fifty 

 species of indigenous trees grown in nurseries and investigated the root 

 systems of a large number of western conifers growing under natural 

 conditons in many habitats from the Black Hills of Dakota to the 

 Pacific Coast. His investigations were confined to the early stages of 

 root growth, namely, the first five years after germination. The results 

 still await publication. Recently Korstian has studied the roots of cer- 

 tain western plants as indicators of conditons of soil moisture. 



Weaver's recent publication contains descriptions of the character, 

 depth and distribution of the roots of about 140 species of plants, none 

 of which, however, are trees. Approximately 1,150 individual plants 

 were examined in eight different communities: (1) Prairies of eastern 

 Nebraska, (2) chaparral of southeastern Nebraska, (3) prairies of 

 southeastern Washington and adjacent Idaho, (4) plains and sandhills 



