Geography
United States
44 results
Texas
9 results
Canada
7 results
Developing countries
7 results
Africa, Sub-Saharan
3 results
Soviet Union
3 results
Africa
2 results
Brazil
2 results
Hawaii
2 results
Africa, North
1 results
Arizona
1 results
Asia
1 results
Bolivia
1 results
Boston
1 results
Burkina Faso
1 results
California
1 results
Caribbean
1 results
Colorado
1 results
Fraser Experimental Forest
1 results
India
1 results
Latin America
1 results
Massachusetts
1 results
Mexico
1 results
Middle East
1 results
Mountain View
1 results
New York (State)
1 results
Oregon
1 results
Pacific Area
1 results
Russia (Federation)
1 results
Sri Lanka
1 results
Sweden
1 results
Tanzania
1 results
Thailand
1 results
Willamette River Valley
1 results