88 CARNEGIE INSTITUTION OF WASHINGTON. 



of the soils has been mapped over a small portion of the valley in which 

 the vegetation has been charted in detail, and is being extended to the 

 entire floor of the valley. A series of photographic records has been 

 begun for certain areas in which erosion is active, and benchmarks have 

 been established from which to secure future measurements of the 

 changes of level to which the floor of the valley is subjected. It is 

 desired particularly to study the deposition and cutting of the incipient 

 streamways, the development of which is retarded by their very slight 

 gradient and by their heavy load of detrital material. Photographs 

 are also being secured as records of the changes of vegetation due to the 

 deposition on portions of the valley floor and the inundations to which 

 it is seasonally subjected. 



A Soil-Temperature Survey of the United States and Canada, by Forrest Shreve. 



The preliminary soil-temperature survey of the United States and 

 Canada, which was begun in 1916 as a committee project of the 

 Ecological Society of America, has been continued during the past 

 year, through the reappointment of a committee consisting of Forrest 

 Shreve, chairman, and Dr. Alfred E. Cameron, of the Dominion Ento- 

 mological Service of Canada. 



In the United States 3 new stations have been added to the 30 in 

 operation during 1917, and observations have been begun at the Domin- 

 ion Experimental Farms in Canada. The location of the new stations 

 is such as to fill some of the largest gaps in the geographical distribution 

 of the older series. Readings at two stations in the Western States 

 have unfortunately been discontinued on account of the curtailment 

 of work at certain of the experiment stations of the Forest Service. 



Special features of soil-temperature work have also been continued 

 by five of the cooperators, giving readings at different depths, and 

 data regarding the influence exerted on the temperature of the soil 

 by its physical character, by the nature of the cover, and by tillage of 

 surface. The complete elaboration of the results of the survey is being 

 deferred until the completion of the third year of continuous observa- 

 tions. 



Stem Analysis and Elongation of Shoots in the Monterey Pine, by Forrest Shreve. 



The Monterey pine {Pinus radiata) is of local occurrence along the 

 coast of central California and is strictly confined to the maritime cli- 

 mate of the "fog-belt." The equable conditions of temperature in this 

 belt give the pine a f restless season varying from 8 to 10 months in 

 length. The rapid growth of the Monterey pine has frequently been 

 noted, but no exact work has been done with it, chiefly owing to its 

 limited occurrence and negligible commercial value. 



