Region
United States
14
West (U.S.)
10
Northeastern States
4
Southern States
4
Rocky Mountains
3
Mexico
2
Southwestern States
2
Arizona
1
Asia, Central
1
British Columbia
1
Fort Valley Experimental Forest (Ariz.)
1
Fraser Experimental Forest (Colo.)
1
Great Plains
1
Hawaii
1
Mexican-American Border Region
1
Middle East
1
North America
1
Northwest, Pacific
1
Rocky Mountains Region
1