Botanists Steve Sillett and Marie Antoine are renowned researchers of old growth forest canopies, especially those of the redwoods of California. The husband and wife team are both Oregon State graduates and reside in Arcata, California, where Steve is a professor in the Department of Forestry and Wildland Resources at Humboldt State University, and Marie is an instructor.
The couple often spend their days climbing more than 30 stories into redwood canopies and studying the ecosystems they find there, which house an incredibly diverse number of species. They are known for hiking into the remotest areas of California’s old growth forest to find the world’s tallest trees, as well as pioneering new methods of climbing them. They are also known for championing old growth forests’ survival, and advocating that industry let trees grow old and large before harvesting. Their work was featured in the October 2009 issue of National Geographic magazine. Recently, Steve and Marie took a few minutes to answer some questions for the Powered by Orange blog.
You are both advocates of letting trees grow old. Who do you think needs the most education in that regard, and why?
MA: Yes, I agree that more trees should be allowed to grow bigger and older. I think it is important for everyone everywhere to consider the implications for carbon sequestration if we were to keep a greater proportion of our landscape covered with long-lived, decay-resistant tree species.
SS: I think foresters need to be aware of the fact that trees can retain growth potential well into old age. The notion that trees become decadent with age is deeply entrenched and has become generally accepted among forest practitioners even though it may not be true. If my recent results from tall species are generally true, this has huge implications for how forests are managed.
What initially compelled you to do this work?
MA: I never knew what I wanted to be when I grew up, but I always suspected that things would unfold well if I kept pursuing things I truly cared about – I wanted to work outside, I loved trees and forests, I felt a deep affinity for unspoiled natural places, I liked to climb things – when I met Steve and learned about the work he was doing, I felt an immediate sense of recognition, like, ‘oh, this is what I’m supposed to do, of course!’ At the time I was already studying lichens in the Douglas-fir canopy, so it was a natural transition to the redwood forest canopy.
SS: I started measuring tall trees many years ago, and this work ultimately led to measurements not just of total height or basal diameter but of their entire crowns. I wanted to know how much foliage, bark, cambium, sapwood, heartwood, and decaying wood these trees carry to get a better handle on how their above ground structure affects their growth as well as provides habitat for arboreal creatures.
What do you see as your greatest teaching challenge?
MA: I am a part-time lecturer at HSU. My greatest challenge is to catch and keep students’ attention, and to show them that the natural world has just as much (or much more) to offer than the internet, video games, TV, and the many other distractions of our consumer society.
SS: My ultimate goal is to change the way people think about forests. There is much still to be learned about how trees work, and this is particularly true in old-growth forests created by tall trees. So much of a tall forest remains hidden from an observer on the ground. When I started climbing trees in the 1980s, I realized how much we have been missing. My life’s work is to speak for the trees and help improve the way humans manage and utilize forests.
Why are ecosystems in the the canopies of redwood trees special? How are they different from the canopies of other big trees? What have you seen up there that has surprised you more than anything else?
MA: The old-growth redwood forest canopy is special in its sheer magnitude. These trees can be 350+ feet tall, with dozens or hundreds of reiterated trunks, giant limbs, and couch-sized fern mats. I could go on and on regarding what’s special about various other forest canopy ecosystems, too. I’m surprised each time I see a wandering salamander up there… it’s so cool that there is enough water stored in the redwood canopy (in arboreal soils and dead wood) that these little lungless amphibians can make a living in this exposed environment. I’m also very happy whenever I see a cyanolichen (nitrogen-fixing lichen), because there aren’t many of those in redwoods.
SS: There is nothing particularly special about redwood forest canopies vs. canopies of other forests except for the fact that redwoods are the tallest trees and hence they create the tallest forests. Douglas-fir and Sitka spruce are two other species that create super-tall forests, and these canopies are just as impressive as redwood forest canopies. In fact, these species can harbor more epiphytes than redwoods do, in part because redwood bark is toxic. But redwoods are more decay- and fire-resistant than other trees, so they live longer than other tall trees and thus attain greater sizes (and have bigger, older limbs).
What do you think about on the way down from the tops of these canopies?
MA: Usually by the time I’m rappelling out of a tree at the end of the day I am tired and hungry. However, there is typically a point where I drop below the lower branches into the bole zone, and I’m reminded how incredibly fortunate I am to get to work in such beautiful and amazing places.
SS: Lots of things, mostly about how nice it will feel to get out of my harness and set my feet on the ground!
And what do you think about as you prepare to pull yourself up 300 feet onto branches that don’t look all that sturdy?
MA: Steve makes the dangerous first ascents into trees. I climb the ropes that he places, so I know that they are over branches that are plenty sturdy.
SS: I try not to dwell on the dangers and instead focus on getting to the top of the rope quickly. Sometimes this is difficult as the rope often slips a bit during the initial ascent, sending stuff crashing to the ground.
What kind of chance to you give the Redwood ecosystems’ survival? Do you think they’re understood and appreciated enough now to persist? Or perhaps to make a comeback?
MA: I have no doubt that the redwoods will survive, as long as the old-growth boundaries are protected and as long as regenerating redwood forests are managed properly.
SS: Redwood forests have a good chance to outlive humans, as they have been around on this Earth for many millions of years whereas we are relative newcomers. I think redwoods should be more widely planted (e.g., Oregon coast range) in places where they could create large-stature forests of the future. Their high-value heartwood is great for carbon sequestration, and if young forests are allowed to grow old enough, they can produce amazing wood for human use.
Is climate change affecting the ecosystems you study?
MA: Maybe, and in the long term, almost certainly. I can’t imagine how any ecosystem on Earth will escape the effects of climate change, habitat destruction, and pollution. Our challenge at this point is to try to mitigate the effects and, most importantly, find solutions for lessening our future impacts.
SS: Yes. Climate change is affecting everything living on Earth. No species is immune.
How did you choose OSU? And how did coming here help set you on your course?
MA: I transferred to OSU from UO my sophomore year to pursue the Nutrition and Food Management major. I’m still interested in the subject, but it wasn’t the career for me. However, during that first year in Corvallis, I discovered backpacking in the Cascades, mountain biking in Mac Forest, rock-climbing at Smith Rock, etc. and realized that I absolutely had to get a major that would allow me to work outside. On the first day of my junior year I switched to Environmental Sciences, and things sort of just fell into place after that.
SS: I chose OSU because I loved Oregon from my days at Reed College and longed to return to the Pacific Northwest after earning my Master’s degree at University of Florida. I do not handle hot humid climates very well, and besides the trees in Florida are puny compared to those here! I also wanted to study with some of the great scientists at OSU, most notably Bruce McCune.
*Photo Credit: © Michael Nichols/National Geographic