June 22, 1917] 



SCIENCE 



639 



the region indicated in the title is 398. We 

 may surmise that no less than 500 actually 

 occur. T. D. A. Cockerell 



ITniveesitt op Colorado, 



BODLDEE, 



May 13 



NOTES ON METEOROLOGY AND 

 CLIMATOLOGY 



PHENOLOGY 



Phenology is the study of the periodic phe- 

 nomena of plant and animal life in their rela- 

 tion to weather and climate. Phenology is 

 most important in forestry, agriculture, horti- 

 culture and ornithology. In spite of the wide 

 application of such data there has been but 

 little phenological observing done in this coun- 

 try. The extent of such work here and abroad 

 is summarized by J. Warren Smith in Monthly 

 Weather Eeview, Supp. 2, October, 1915, in 

 connection with the remarkably long and ex- 

 tensive records of Thomas Mikesell at Wau- 

 seon, Ohio. These Wauseon records began in 

 part in 1869 and are published including 1912 ; 

 complete data are given concerning 114 kinds 

 of wild plants, 48 forest trees, shrubs and 

 vines, 16 kinds of fruits, 20 field and garden 

 crops (with yields of some), and the tempera- 

 tures, rainfall, frosts and first and last snows. 

 In parts of Europe similar records though of 

 fewer plants have been taken by many observ- 

 ers in the British Isles for more than 20 years 

 and in Hessen 33 years.^. Ihne^ in charge of 

 the latter has made a map of phenological 

 spring, and also compared the distribution of 

 population with the phenological maps. 



The Bureau of Entomology and the Forest 

 Service are studying phenology as an aid in 

 planting and cutting trees and in the control 

 of pests. 



Dr. A. D. Hopkins, of the former, has formu- 

 lated in a general way the law of phenological 

 variation as follows :^ " The average varia- 

 tion in the dates of a phenological phenomena 



1 Quart. Jour. Eoy. Meteorological Soc., J. E. 

 Clark — 13 common plants, 6 birds, 5 insects, more 

 than 100 stations. 



2 ' ' Arbeiteu der Landwirtschaf tskammer fur das 

 Grosherzogtum Hessen. ' ' 



8 ' ' Report on Forest Trees, ' ' 1914. 



of a species is in uniform proportion to the 

 variation in the controlling factors of cli- 

 mate." The general average is the only one 

 for drawing reliable conclusions. A variation 

 of 4 days is to be found with a difference of 1° 

 in latitude, 400 feet in altitude, 5° in longitude 

 westward, or 1° F. The longitude variation 

 seems to be connected with the increasing dry- 

 ness and strength of sunlight for the Central 

 United States, and with the warmth of the 

 Pacific as the west coast is approached. De- 

 partures from the theoretical are the result of 

 local factors. Prevailing sunshine, aridity, 

 absence of large bodies of water, warm ocean 

 currents, prevailing warm winds, S., S.E. and 

 S.W. slopes, narrow summits or plateaus of 

 hills and mountains, broad valleys, open for- 

 ests, barren or sandy and dry soils — these are 

 accelerating; the opposite conditions are re- 

 tarding. The size of departures are roughly 

 as follows: error in interpretation, 2 days; 

 southern or northern slopes 1 to 4 days, other 

 retarding or accelerating factors, 1 to 4 days, 

 early and late individuals 1 to 8 days, coastal 

 influences 10-14 days. 



The results of collection made by the Forest 

 Service of a large amount of phenological data 

 on 72 common trees in the eastern United 

 States is published in Monthly Weather Re- 

 view, Supp. 2, October, 1915, pp. 5-9 inch, " A 

 Calendar of the Leafing, Flowering and Seed- 

 ing of the Common Trees of the Eastern 

 United States," by George N". Lamb. The 

 dates are given only for the extreme north and 

 south limits of their ranges. Further coopera- 

 tion in the collection of such data is desired 

 by the Forest Service. 



In agriculture, phenology contributes not 

 only to the control of pests, but also is of use 

 in determining the proper dates for planting 

 certain crops. On the basis of a thorough 

 study of the Hessian fly at one or more control 

 stations in West Virginia, Dr. Hopkins was 

 able to construct a map and table with which 

 if he knew his location and altitude a farmer 

 could plant his winter wheat during a short 

 period immediately after the usual disappear- 

 ance of the Hessian fly. In the spring, wild 

 plants are used by many to indicate the proper 



