Stephen C. Sillett (born March 19, 1968) is an Americanbotanist specializing inold growth forest canopies. As the first scientist to enter theredwood forestcanopy, he pioneered new methods forclimbing, exploring, and studying tall trees.^[1] Sillett has climbed many of the world'stallest trees to study the plant and animal life residing in their crowns and is generally recognized as an authority on tall trees, especially redwoods (Sequoia sempervirens).

He is the firstKenneth L. Fisher Chair in Redwood ForestEcology for the Department ofBiological Sciences atCal Poly Humboldt. He is featured inRichard Preston'sNew York Times best sellerThe Wild Trees, as well as in academic journals, general interest magazines, and nature television programs. He lives inArcata, California, with wife Marie Antoine, a botanist and fellow forest canopy research scientist.^[2][3]

Sillett was born March 19, 1968, inHarrisburg, Pennsylvania. He has a younger sister, Liana, and an older brother, Scott, who is also featured inThe Wild Trees. Both Sillett brothers were inspired to pursue careers in science by their grandmother, Helen Poe Sillett, who was a bird enthusiast.^[4]

Sillett studiedbiology as an undergraduate atReed College inPortland, Oregon, to pursue his interest in botany, later refocusing on tall trees andLobaria, a type ofnitrogen-fixinglichen associated withold-growth forests, in thePacific Northwest. He received his Bachelor of Arts in 1989. He went on to receive aMaster of Science in Botany from theUniversity of Florida in 1991, and aDoctor of Philosophy fromOregon State University in 1995.

Sillett began teaching atCal Poly Humboldt in 1996, where he dedicates much of his time to field study of not only coast redwood but also giant sequoia (Sequoiadendron giganteum), Douglas-fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), and the tallest trees of the Southern Hemisphere,Eucalyptus regnans andE. globulus. He currently teaches courses in General Botany,Lichens andBryophytes, and Forest Canopy Ecology at Cal Poly Humboldt.^[3]

Sillett beganclimbing Douglas-fir trees during his undergraduate years at Reed College. While working on his Masters, he studied acloud forest canopy inCosta Rica, focusing on bryophytes inhabiting the emergent crowns of strangler figs (Ficus tuerckheimii). His doctorate work focused on old-growth Douglas-fir forests in theCascade Mountains of westernOregon. It was not until he began teaching at Cal Poly Humboldt that he began climbing and studying redwood forests.^[4]

After moving to northwestern California, Sillett began studying old-growth redwood forests and thebiodiversity found in their canopies. Additionally, Sillett studies how water is transported up the tree in an effort to understand the limits to tree height. One of his chief interests is in determining the maximum attainable heights of the 6 tallest tree species.^[4]

To reach the canopies, he uses an arrow to set a climbing line, then ascends using a modified arborist-style safety swing involving ropes, leather harnesses, andpulleys. Once in the canopy, Sillett and his research crew move about in a style known asskywalking using motionlanyards on a web of climbing ropes. To reach outlying branches, Sillett deploys aTyrolean traverse between adjacent trees.^[5]

In addition to studying redwood canopies, Sillett studies other tall forests in the US, Canada, and Australia. He has climbed and measured the tallest of each of the six tallest trees species. Sillett and his team do not disclose precise locations of the world's tallest trees. Sillett allows only students and research team members to climb with him, to maintain both the security of the trees and the safety of fellow researchers.^[6]

• Discovery of the redwoodGrove of Titans in 1998, accompanied byMichael Taylor.^[4]
• Sillett began climbing redwoods in 1987, becoming the first scientist to enter the old-growth redwood forest canopy.^[4]
• He has climbed and measured the height of the tallest knownlive-topped tree of each of the five tree species known to grow over 100 m (300 ft) tall.^[7]
• In 2006, Sillett measured and verified the redwoodHyperion as the world's tallest tree at 115.55 m (379.1 ft). Previous record-holderStratosphere Giant is 112.83 m (370.5 ft).^[6]
• Sillett is the first holder of theKenneth L. Fisher Chair in Redwood Forest Ecology at Cal Poly Humboldt. This is the world's first and only endowed chair supporting the study of one tree species. Theendowment is designed to promote field research of redwood canopies.^[7][8]
• Sillett, wife Marie Antoine, brother Scott, and other climbing and research companions including Michael Taylor and Chris Atkins are featured in Richard Preston's bookThe Wild Trees.^[4] The book details some notable climbs, including his first ascent into the crown of a tall redwood tree.
• Sillett's research has been published in a number of academic journals includingNature, theAmerican Journal of Botany,Ecological Monographs,Ecological Applications,Bryologist,Northwest Science, andMadroño. His research has also been profiled inThe New Yorker (by Richard Preston),^[1][9]Discover,^[10]New Scientist,^[11] andNational Geographic.^[12]
• Sillett has been profiled on nature television programs such as National Geographic'sWild Chronicles,BBC'sPlanet Earth, andPBS'sOregon Field Guide.^[3]
• Sillett was named Scholar of the Year atCal Poly Humboldt in 2006.^[13]

His wife, Marie E. Antoine, a fellow botanist, lectures at Cal Poly Humboldt and assists Sillett in his field research. They were married on December 8, 2001.

In addition to being a Grantee to theSave the Redwoods League, some of Sillett's awards and acknowledgments include:

• The William Sterling Sullivant Award for Best Bryophyte Paper (1995)
• ANational Science Foundation Fellowship
• The Beinecke Brothers Memorial Scholarship^[14]

Affiliations include:

• Ecological Society of America
• American Bryological and Lichenological Society
• Northwest Scientific Association
• California Native Plant Society
• California Faculty Association
• International Canopy Network^[14]

• Sillett, S. C., and R. Van Pelt. 2007. Trunk reiteration promotesepiphytes and water storage in an old-growth redwood forest canopy.Ecological Monographs, in press.
• Williams, C. B., and S. C. Sillett. 2007. Epiphyte communities on redwood (Sequoia sempervirens) in northwestern California, USA.Bryologist 110:420-452.
• Woolley, L. P., T. W. Henkel, and S. C. Sillett. 2007. Reiteration in the monodominant tropical treeDicymbe corymbosa and its potential adaptive significance.Biotropica, in press.

• "Climbing the Redwoods," Richard Preston,The New Yorker, February 14, 2005, p. 212^[1]
• "Tall For Its Age," Richard Preston,The New Yorker, October 9, 2006, p. 32^[9]
• Preston, Richard (2007).The Wild Trees: A Story of Passion and Daring.Random House.ISBN 978-1-4000-6489-2.

• 1968 births
• Living people
• People from Harrisburg, Pennsylvania
• American ecologists
• Oregon State University alumni
• University of Florida College of Liberal Arts and Sciences alumni
• Reed College alumni
• California State Polytechnic University, Humboldt faculty
• Forestry academics
• People from Arcata, California
• American foresters

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• Short description is different from Wikidata
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