He earned his doctorate investigating physiological limits to tree growth at timberline and then devoted much of his career to the study of diverse forest, tundra, and, more recently, desert ecosystems, traveling widely throughout North America and Europe.
(He; devoted; much of his career to the study of diverse forest, tundra; T:then) (He; earned more recently; traveling widely throughout North America and Europe) Context(He earned more recently,List([0, 182))):(He; earned more recently investigating; physiological limits to tree growth at timberline)
He earned more recently,List([0, 182))
He He He
devoted earned more recently earned more recently investigating
much of his career to the study of diverse forest, tundra T:then
traveling widely throughout North America and Europe
physiological limits to tree growth at timberline