File:The distribution of vegetation in the United States, as related to climatic conditions (1921) (20977199025).jpg

Title: The distribution of vegetation in the United States, as related to climatic conditions
Identifier: distributionofv00livi (find matches)
Year: 1921 (1920s)
Authors: Livingston, Burton E. (Burton Edward), 1875-1948; Shreve, Forrest, 1878-1950
Subjects: Phytogeography
Publisher: (Washington) Carnegie institution of Washington
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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380 ENVIRONMENTAL CONDITIONS. We have prepared another chart of this kind by superimposing the chart of the physiological summation indices of temperature for the average frostless season (plate 40 and fig. 1) upon that of the precipi- tation-evaporation ratio for the average frostless season (plate 57 and fig. 16), and the result is shown in figure 19, where the broken lines represent temperature conditions and the full ones represent condi- tions of moisture. On this chart each of the five temperature provinces is subdivided into four moisture provinces and the country is thus represented as a mosaic of small areas of various shapes and sizes, each area being characterized by a certain range and amplitude of the temperature index and also of the moisture index. Following our previous usage, climatically descriptive adjectives may be employed 29° 127° 125° 123° 121° 119° 117° 115° 113° 107° 105° 103° 1U1° 89' 97° 95 81° -9° 77° 75° 73° 71" G9° 07°
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Fig. 19.—Two dimensional moisture-temperature provinces, being a combination of figures 1 and 16. Broken lines limit temperature efficiency provinces (fig. 1), full lines limit precipitation- . evaporation provinces, (fig. 16). (See also Plates 40 and 57.) in designating these ranges of index values, and two such adjectives sufl&ce to describe any one of the irregular areas shown on the chart. Thus, we may refer to the warm semiarid 'province, the medium humid province, the cool semihumid province, etc., each of these provinces including the coincident or overlapping portions of the corresponding temperature and moisture provinces. An examination of figure 19 shows, however, that several different geographical areas may be characterized by the same pair of adjectives, and these may be designated by geographically descriptive terms,

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