Biography

American botanist and climatologist. Holdridge specialised in tropical forestry, in which he was a renowned expert, but he is best known for developing the 'Life Zones of the World' ecological classification system, which charts tropical ecosystems according to climate and vegetation zones. He first published the life zones chart in 1947 and updated it in his 1964 book, Life Zones Ecology, and it has since been used throughout tropical countries in Latin America as a frame of reference for agricultural improvement experiments, and by NASA in its models of climate change. He also gained recognition for establishing the research station La Selva in Costa Rica.

Leslie Rensselaer Holdridge was born in Ledyard, Connecticut, and studied forestry at the University of Maine, graduating in 1931. He went on to work as a reforestation foreman in the Kisatchie National Forest, Louisiana, before moving to Puerto Rico in 1935 where he was appointed head of the planting department for the Caribbean National Forest (1935-1938) and then forester for the U.S. Forestry Service (1938-1941). In the 1940s he managed the forestry division of the Haitian rubber production company, Société Haitiano-Americaine Development Agricole, and also carried out research on cinchona in Colombia and Guatemala. In 1947 he gained his PhD in botany from the University of Michigan, in which year his first version of the life zones chart also appeared in a paper entitled "Determination of World Plant Formations from Simple Climatic Data", published in Science.

Holdridge moved to Costa Rica in 1949, taking up directorship of the Inter-American Institute for Cooperation on Agriculture from 1950-1951 and remained as head of its natural resources department until 1960. During this period he established La Selva research station, its mixed plantations offering a site for experimentation with new methods of natural resource management. La Selva was later purchased by the Organisation for Tropical Studies (OTS) and is now one of the foremost tropical rain forest research stations.

In the 1960s Holdridge worked as a private ecological consultant and on Central American fieldwork for the Associated Colleges of the Midwest, before founding Costa Rica's Tropical Science Centre in 1967. Five years after publishing Life Zone Ecology he was awarded the Inter-American Medal of the Inter-American Institute of Agricultural Sciences (1969) and in 1971 published another influential work, Forest Environments in Tropical Life Zones. He spent four years as a part-time professor of ecology and dendrology at the Costa Rican Instituto Tecnológico (1978-1982) before retiring. He lived in Costa Rica until well into his eighties, when he lost his eyesight. He died in Easton, Maryland. At least nine angiosperm species have been dedicated to Holdridge, including Sacoglottis holdridgei Cuatrec. (Humiriaceae), the dominant tree species of Isla del Coco.

Sources:
Anon., 1999, The Cutting Edge, 6(3):
http://www.inbio.ac.cr/papers/manual_plantas/jul99/jul99not.html
C.H. Smith, 2007, "Some Biogeographers, Evolutionists and Ecologists: Chrono-Biographical Sketches":
http://www.wku.edu/~smithch/chronob/HOLD1907.htm
F.H. Wadsworth, 1999, "Leslie R. Holdridge, 1907-1999", International Society of Tropical Foresters News, 20(3): 3
Botanical Society of America, Scott A. Mori, How I became a Tropical Botanist:
http://www.botany.org/profiles/scott_mori.php
IICA Honors; Outstanding Contributions to Agriculture:
http://www.iica.int/Eng/regiones/norte/usa/IICA%20Office%20Documents/iica_screen.pdf.