352 CARNEGIE INSTITUTION OF WASHINGTON. 



Succession in Inland Dunes and Sandhills, by F. E. Clements. 

 In connection with the developmental study of the climaxes of the West, 

 the seres of dunes and sandhills have been under investigation since 1914. 

 During this time the large majority of inland dune and sandhill areas from 

 Nebraska to California have been visited, some of them several times, and 

 some comparative studies have been made on the dunes of the California 

 coast. Most of the areas concerned he within the grassland climax, but 

 dune areas of importance occur also within the sagebrush and desert-scrub 

 climaxes. During the present season such areas have been visited in the 

 Colorado Desert, near Fallon, Nevada, in eastern Colorado and southern 

 Nebraska, at Eufaula, Oklahoma, at Burkburnett and Quanah on the Red 

 River, at Odessa and El Paso, Texas, and at Deming, New Mexico. While 

 the early stages of all the areas studied have much in common, they naturally 

 diverge more and more as the various climaxes are approached. In some 

 cases at least the formation of dunes appears to be related to climatic cycles, 

 and an attempt is now being made to correlate this with other cyclic phe- 

 nomena. 



Permanent Quadrats and Tristats, by F. E. Clements, E. S. Clements, and 



J. V. G. Loftfield. 



In addition to maintaining the quadrats, transects, and tristats already 

 installed, a considerable number of new ones has been established. The 

 Hill pantograph and the methods of charting and record have been further 

 improved and a new unit for volume measures has been devised. This is 

 termed a cubon; it is designed to permit the counting or charting of organisms 

 in unit volumes of the soil or the air and, to a certain degree, in water. The 

 community chart has been further developed and modified to serve a variety 

 of purposes. The quadrat has been adapted to life-history studies by means 

 of charting at intervals of 2 weeks or a month during the growing season 

 and at longer intervals between. This permits a record of the growth and 

 spread of the plant from the appearance of the seedling or shoot through 

 flowering and fruiting to the time of its disappearance or entrance into the 

 resting period. The overhead method of quadrating by means of the camera 

 has been perfected, and it is being employed in the field to determine the 

 different uses to which it can be profitably put. It is thought that it can be 

 combined with the tristat to give a complete picture of the structure and 

 setting of any part of a plant community. The development of quantitative 

 measures of vegetation has been rapid during the past 5 years, and it is 

 planned to make the new methods available to working ecologists, together 

 with some account of the results to be obtained by their use. 



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

 In addition to the usual field work on overgrazing, carrying capacity, 

 indicators, and the effect of climatic cycles on the growth and composition 

 of grasslands, the projects at the 3 cooperative stations have been con- 

 siderably expanded. At the Santa Rita station, 24 new seedling quadrats, 3 

 additional burn quadrats, and 5 special quadrats have been installed, in 

 addition to transects for determining the effect of clearing off scrub upon the 

 behavior of the grasses. The relation of burning to composition and growth 

 is being followed in communities of native grass, in scrub and savannah, and 



