U. S. DEPARTMENT OF AGRICULTURE 
CLIMATIG PROVINCES AND 
129° 12% 125° 123° 
V 
121° 
2M) 
= 
a Y 7 
Sev 
= 
y 
0S 
eS 
A, Fi 
Cb ; 
Yi, OX 
yf 
Cal ee 
25° (GS ea 20 | EB’ 21 _JeEC’d 
bea] 
Mize 
PLANT GROWTH REGIONS OF THE UNITED STATES 
Od 
NWN 
* CLIMATIC PROVINCES 
y ps AC'r 
[ee EB ec: 
GW ec's 
wy co'r 
11] Cc’s 
[44 ]ccra 
HUMIDITY 
PROVINCE 
A Wel 
B Humid 
C Sub-Humid 
D Semiarid 
E Arid 
KEY TO SYMBOLS 
TEMPERATURE 
PROVINCE 
A’ Tropical 
B’ Mesothermal 
C 
D 
E 
Microthermal 
" Taiga 
’ Tundra 
' adequate at all seasons 
Ss summer deficiency 
d deficiency at all seasons 
SEASONAL DISTRIBUTION alle 
OF PRECIPITATION 
Examples: 
121° 119° 117° 15° 113° We 
era Wet, Mesothermal, Adequate at all seasons. 
{2 ] Wet, Microthermal, Adequate at all seasons. 
P| 
Humid, Tropical, Adequate at all seasons. 
Humid, Mesothermal, Adequate at all seasons. 
Humid, Microthermal, Adequate at all seasons, 
North Pacific Coast. 
Central California Valleys. 
Cascade - Sierra Nevada. 
Southern California. 
Columbia River Valley. 
BENal| 
On how _— 
Climatic Provinces by C. W. Thornthwaite. Soil Conservation Service, U. S. D. A. 
Plant growth Regions by Furman Lloyd Mulford, Bureau of Plant Industry, U. S. D. A. 
Humid, Mesothermal, Summer deficiency 
Humid, Microthermal, Summer deficiency. 
Subhumid, Mesothermal, Adequate at all seasons. 
Subhumid, Microthermal, Adequate at all seasons. 
Subhumid, Mesothermal, Summer deficiency. 
Palouse - Bitterroot Valley. 
Snake River Plain- Utah Valley. 
Great Basin - Intermontane. 
Willamette Valley -- Puget Sound. 
Southwestern Desert. 
Southern Plateau. 
Northern Rocky Mountains. 
SOIL CONSERVATION SERVICE 
147° 
45° 
EB’d—arid, mesothermal, moisture deficient _— 
at all seasons (El Paso) 
DB’s—semiarid, mesothermal, summer dry 
climate (Los Angeles) 
Scale in Miles 
100 50 25 0 50 100 
LEGEND FOR CLIMATIC PROVINCES 
{a7} Subhumid, Microthermal, Summer deficiency. 
[£53259]: Subhumid, Tropical, Deficiency at all seasons. 
Subhumid, Mesothermal, Deficiency at all seasons. 
300 
Subhumid, Microthermal, Deficiency at all seasons. 
Semiarid, Mesothermal, Summer deficiency. 
LEGEND FOR PLANT GROWTH REGIONS 
Central Rocky Mountains ISS 18 Northern Black Soils. 
Southern Rocky Mountains. 19 Central Black Soils. 
Northern Great Plains. 20 Southern Black Soils. 
Central Great Plains. 21 Northern Prairies. 
Southern Plains. Ss 22 Central Prairies. 
Sita 95° 93° 
gI° 
AS 28) 
10 24 
(a25 
WZ 26 
Rees] 27 
Semiarid, Microthermal, Summer deficiency. 
Semiarid, Mesothermal, Deticiency at all seasons. 
Semiarid, Microthermal, Deficiency at all seasons. 
Arid, Tropical, Deficiency at all seasons. 
Western Great Lakes. 
Central Great Lakes. 
Ozark - Ohio - Tennessee River Valleys 
Northern Great Lakes -St. Lawrence. 
Appalachian. 
Arid, Mesothermal, Deficiency at all seasons. 
Arid, Microthermal, deficiency at all seasons. 
Taiga. 
Tundra. 
Piedmont. 
Upper Coastal Plain. 
Swampy Coastal Plain. 
South - Central Florida. 
Subtropical Florida. 
Lith, A, Hoen & Co. 
\J 
TS. 
43° 
39° 
Siva 
Sou 
33° 
31° 
_—| 29° 
255 
Map prepared by Cartographic Drafting Unit 
