Do you think about geometry and physics while climbing a tree?
Erik Saunders does, because his life depends on it.
Erik Saunders uses ropes, knots and protective gear to scale tall trees.
(Ann Cameron Siegal For The Washington Post)
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A Tree by Any Other Name?
Everyone knows what a tree is, right? To be a tree, a plant must:
• Be a woody plant.
• Have a single, straight trunk that is at least three inches across.
• Grow taller than 13 feet (this is true for most trees; a few are smaller).
• Have a "crown" of leaves that you can easily see.
There are more than 700 types (species) of trees in North America, and 100 of them are pretty common. Don't confuse a tree with a shrub, a short, woody plant that has a lot of stems instead of one trunk. And a vine is a woody plant that grows on a single stem, but is much thinner than a tree.
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Saunders, 37, is a climbing arborist. His work often takes him 60 feet or more above the ground, where he expertly moves among tree branches, using a chain saw to prune healthy ones and cut off dying ones. Saunders's nickname is Spiderman.
When Saunders was young, he loved being outdoors so much that his uncle said, "He's not a boy, he's a wood animal."
In high school, Saunders found biology fascinating. "I always considered trees to be real live organisms, not just things that get in the way." He took a college course in dendrology, or tree identification. (Did you know that there are more than 25 kinds of oak trees on the East Coast?)
After talking to people who had tree-related jobs, Saunders decided to become an urban forester and work with trees around homes and businesses. To move from limb to limb and bring down branches safely, Saunders must have detailed understanding of pulleys, levers, inclined planes, angles, knot-tying and Isaac Newton's laws of motion.
On the job, Saunders is outfitted much like a rock climber, wearing a hard hat and strapped into a saddle (harness) for back support. He maneuvers around each tree using a series of ropes and a knot called a Blake's hitch.
He also has to know about wood characteristics. "When I wrap a rope around a limb, it has to be able to hold my weight," said Saunders, who is 5 feet 11 inches tall and weighs 200 pounds. Because oaks are strong, he can tie on to a limb as small as his wrist, but that's not the case for tulip poplars or pines, which have much weaker branches.
Shouting "timber!" as branches drop sounds like fun, doesn't it? Well, not exactly. In Saunders's business, no one yells "timber." A shout of "headache!" is the standard warning before a branch is cut. This alerts the ground crew to get out of the way. The final cut is not made until the crew shows it has heard the warning.
Saunders doesn't drop tree limbs randomly either. He knows exactly where a branch is going to land before he cuts it off. That's where geometry comes into play.
A lowering line is tied to the tip of a limb, but before the cut is made near the trunk, Saunders draws angles in his mind. "The art of rigging is the most challenging," he said. "I have to send the branch to the ground under control."
Tree work can be dangerous, and Saunders must think several steps ahead. What if a rope breaks? What if a strong wind comes? Understanding motion and force helps him anticipate problems and react quickly to keep himself and his crew safe.
The work also requires incredible arm and leg strength. "The tree is my gym," he said. When climbing, he wears 10 pounds of gear and carries a 12-pound chainsaw and about 20 pounds of rope.
Saunders says that studying martial arts has helped make him more confident and focused.
But, he added, "You do have to be a little goofy to do this."
