296 CARNEGIE INSTITUTION OF WASHINGTON. 



in plant terms to a large degree. This can be done only by means of 

 permanent quadrats and definite vegetational experiments carried 

 through a series of years, preferably the 12 to 15 year period of a sun- 

 spot cj^cle. As a consequence, an especial endeavor has been made 

 during the year to select locations for permanent quadrats in the 

 various climaxes and their most important serai areas. Some of 

 these have already been installed and charted at such widely sepa- 

 rated points as Tucson (Arizona), La Jolla (California), Eugene and 

 Bend (Oregon), Logan (Utah), Colorado Springs, etc. A consider- 

 able number have also been installed in connection with cooperative 

 studies on carrying capacity and the effect of eradicating rodents 

 from grazing ranges. It is hoped to increase the number until every 

 climax is adequately represented in its various associations and to make 

 the most important of the quadrat installations regional centers for 

 quantitative studies and vegetation experiments. In the attempt 

 to secure a record of plant parts below ground, a quadrat-bisect method 

 has been devised by which depth, spread, and competition relations 

 may be charted for the wet and dry phases of the cycle. 



Indicator Plants, by F, E. Clements. 



The special study of indicator plants carried on during the past 

 five years has been completed, and the results have been embodied 

 in a book to be published during the year. It has become more and 

 more evident that indicators are of the greatest importance prac- 

 tically as well as scientifically. Hence, a particular effort has been 

 made to render the results of the widest service to agriculturists, 

 foresters, and grazing experts, as well as to ecologists. For this reason 

 an account has been given of the results of other investigators in 

 so far as they deal directly with indicator values. While it has 

 proved possible to greatly increase the number of indicators and to 

 definitize their meaning and application, it is recognized that precise 

 quantitative values can be assigned to but few at present. In spite 

 of this the general values which can be given mark a decided advance 

 in our knowledge, and permit the outlining of a definite system of 

 indicators which can be filled in as experimental and quantitative 

 investigations increase in number. 



Grazing Research, by F. E. Clements, Edith Clements, and G. V. Loftfield. 



Grazing problems have constituted one of the major lines of 

 research throughout the year. Because of their emergency nature 

 under war and drought conditions, a vigorous effort has been made 

 to secure effective cooperation throughout the West. This has been 

 remarkably successful, with the result that the Institution is now 

 cooperating informally but effectively with several bureaus of the 

 Department of Agriculture and the majority of the western experiment 



