Sunday felt like a good day for another tree climb, so my roommate Nels and I loaded ourselves down, left the house, and began walking in the direction of East River Flats.

I keep thinking I should just go ahead and buy myself a harness, but they're $38–$70 and I can rent one for three days for $2.50. The economics of renting make some sense in the short-term, but no the long-run.

However, some features of the harness-to-be are becoming clear. It should have good pads for the legs, none of this seatbelt-junk. The front should tighten from both directions, to keep the belay loop (comfortably) centered. The haul-loop should be full-strength so I can hang from that, if necessary. Full-strength gear loops would also be nice. Self-double-backing buckles are a nice bonus.

Granted, any rock climbing harness is going to be a little uncomfortable for tree climbing. They're meant to be minimalist, body-conforming harness that you can ignore while scaling rock faces and which catch you when you fall. They're not really designed to be sat in while you work your way up, hanging on them, into a high tree.

Here, let me show you.

These are rock climbing harnesses. The one on the left is a minimalist "seatbelt" harness—the sort of thing you rent for a few bucks when you go to the climbing gym. It protects you from falls, but isn't too comfortable and doesn't have any useful loops for hauling gear around. The one on the right is a higher end rock climbing harness. You'll notice that the back and leg loops are larger and padded to distribute weight. There are a few extra loops on the sides for hanging gear on, the leg loops are separated from the body of the harness for comfort and flexibility, and the waist has two buckles.

These are tree climbing harnesses. You'll notice right away that there is much more padding. The harnesses are generally of a more rugged design, in some cases leather or other difficult-to-cut materials are incorporated (these harness are used primarily by people dangling from ropes while wielding running chainsaws). In some designs the dual leg-loop design is replaced with a single strap (sometimes incorporating an actual plank to make a firm seat). Most of these harnesses have D-rings on either side, offering alternative connection points to the tree.

Alas, these harness typically run around $200 and, while a rock climbing harness will work well-enough for tree climbing, the reverse is not necessarily true. So far I've spent about $160 in equipment for tree climb, which isn't bad. But there are still some things I'd like to get ahold of.

[Update (08/11/02012): I've tried the harness on the far right and it tends to squish one's legs together uncomfortably while simultaneously making movement difficult. Best to be avoided.

On the low-end, a little spool for my throw line would be nice—it's difficult to manage sometimes. And some sheets or tarps to run the rope off of the ground. Grit and such eats away at the rope's tiny fibers, making it weaker. This is especially important for my rope, which is braided and unsheathed. Speaking of which, moving up the price scale, it would be nice to get a sheathed rope (~$150). Not only because this would keep the grit out, but also because it would permit use of mechanical ascenders (~$65). These may or may not be safer, but they'd probably be quicker to climb with and would definitely make branch-walking easier. A sheathed rope would also be good because no matter how many times you tell people not to step on the rope, they do. And that's bad for it. Also, a decently-powerful laser. Trying to point out a target branch from the ground is a difficult exercise in description and pointing with one's finger doesn't work when a dense crown is sixty feet away.

Nels and I reach the mall and are walking past a girl busy doing homework, when her protractor slips out of her hands and falls in front of us. We advise her to keep better track of it, because "protractors are wily", and continue over to Walter Library. Nels, looking up, says that this is his favourite tree.

I've looked at it before. It's a beautiful, spreading elm. From the ground it's debatable how much movement will be possible in the crown, but… it is Nels's favourite tree. So I take out the throw line, biff the first few shots, hit the branch on the next two, and, on the seventh throw get it into the tree. I used to kind of lob it upwards, depending primarily on luck, but I've since discovered that if I just think about it a little more, I tend to be much more accurate.

I run Nels through the knots. The system incorporates five of them. I tie the three that support the climber's weight and then pass these around as necessary so they needn't be retied by anyone else. The other two knots are simple and provide back-up and mobility. This is handy when one is in the tree because the weight-bearing knots do not bear weight until they've borne weight; which is to say, they tend to slip slightly when you first use them. No problem on the ground, slightly terrifying at sixty feet.

The branch I've chosen is perhaps forty or fifty feet up, so it's shaping up to be a long climb. After about ten feet, I decide it's time for an experiment. I learned how to climb ropes in circus and at one point was able to do so by gripping the rope between my big toe and the toe next to it, walking upwards this way. Now that my callouses are gone, I prefer a simple foot-lock. I disconnect my foot-loop and WOW is it faster! I also learned a couple of things right away. Since this is faster and puts your body in different positions with respect to the rope, it's important to put the gate of the carabiner away from the dangling end because the gate stands a chance of fraying the rope as it goes upwards and the rope stands a chance of unscrewing the gate-lock.

I like to choose branches whose fall-line intersects another branch before hitting the ground. That way, I have something to stand or sit on when I get up there; today's branch turns out to be about three feet from the fall-line, so I have to reach out and grab it with my legs and then twist—hard—to get on. The branch is about a foot-wide, so it's easy to stand up. Now, where to go?

Looking trunkwards of my position, I see that the branch curves downwards six or seven feet coming to a kind of crotch. The main trunk of the tree rises upwards and then splits in three directions at once, leaving a kind of platform. I slack the rope, leaning backwards and away from the branch for stability, and begin walking down the curve. This is my third branch-walking experience and the most epic yet. Despite this, the trunk is an easy target.

Inside, the tree is spectacular! From my position, several branches, including the one I've just come in on, arch counter-trunkward offering twenty to thirty feet of walking space. The three "sub-trunks" split out in different directions with no sign of cracking or stress. Between them and above me is a wide area of free space surrounded by limbs suitable for possible anchoring. High on my todo list is some practice at three-space movement, where I use two systems and move between them.

But I'll leave all that for later. I tie onto an overhead branch and send the loop down to Nels. I've found the first ten feet or so are the most difficult for people as they try to establish a rhythm and cope with moving the knots. After that, things tend to go smoothly.

When I first began taking people up with me, I debated about whether it was better to be on the ground or in the tree. An optimal situation would be having someone knowledgeable at both ends. As it is, I elect to stay in the tree. I figure if something's going to need to be sorted out, it's probably going to be in the air. Looking down, I can tell from the general shape of the knots being tied and the arm movements of the people tying them whether they're correct or not; add to this that the knots' aesthetic and function both define a proper form that would be difficult to mess up.

This squirrel had never seen anything like this in its tree before and kept staring at me from different angles, just a few feet away

There are, I think, only two ways to accidentally mess up the system. One is unscrewing your carabiner's gate. This happened to me—twice—on this climb, so I think perhaps I've been screwing the gate too loosely; if it happens again, I'll buy a new set of carabiners with a different locking mecahnism that isn't vulnerable to this problem. How much of a problem is unscrewing the gate? From a physical perspective, having the gate open turns at 24kN carabiner into a 7kN carabiner (the strength decreases from 5,395lbs to 1,574lbs), which is still more than sufficient to hold a person up. Provided you're not falling on the carabiner, which is to be avoided anyway.

Pragmatically, it depends on the position you're in. Climbing the tree is probably the most dangerous place for this to happen because your weight alternates between the carabiner and the foot-loop, leading to slack. When you're in the tree the line is generally under tension and less likely to pop out through an open gate. Still I have to keep an eye out for this. [Update (9/4/02011): In another ascent with Kathur on a different tree, we had no problems with the gates.] [Update (8/11/02012): This problem has still not occurred again.]

The other potential accident is to grab the ascension knot. By design, doing this causes the knots to descend the rope—which I can tell you is really handy for getting out of the tree. After trying it both ways, I now generally wait until a climber's six or seven feet of the ground before telling them about this, my idea being to give them a chance to use and gain trust in the rope before pointing out a very manageable pitfall. The worst-case scenario is that the climber grabs the knot, feels it sliding, panics, and grabs the knot harder. To protect against this, we leave a series of safety knots in the rope.

When climbers descend, they either tend to pull too little, failing to put the knot into “descend mode”, or pull too hard, dropping a foot or two before stopping, bodies full of adrenaline. It reminds me a lot of a scooter I rented in Greece; it's important to try to get people on the safe end of the spectrum.

Nels makes it up into the tree and begins to look around. As he's doing so, we here a voice from below, "So how do you keep track of a wily protractor?" Nels and I have a shouted conversation back and forth and, when he's ready to head down we decide to invite her up.

Caiol's climb goes well, though at some point she hits a kind of “fear wall” and has to stop briefly. Shortly, she continues upwards. After introducing a number of people to rock climbing and tree climbing it seems as though there's some distance above the ground where people feel out of their comfort zone. For some people that's anytime their feet leave the ground, but for most it seems to come between ten and twenty feet… I wonder if any research has been done on this. As Caiol gets up among the branches she tells me that having them around makes her feel safer, so maybe it's three-space that people are afraid of. As you get higher on the rope, you can hear creaking sounds: the leather cambium saver interacting with the bark. A harmless, but somewhat alarming sound that freaked me out the first couple of times I climbed until I figured out what it was.

Caiol's not feeling like branch-walking (understandably), so I throw out a line and tow her back into the tree to have a look around.

Which, of course, is the exact moment a police car drives up.

A little earlier an old guy with a foreign accent had walked by, looked up, and asked if we needed help. Nels had gone over and told him no, that we were fine, but he'd continued to walk around. And now, somewhere below us, a cop is shouting indistinctly upwards that we need to get down… for our own protection.

The situation makes me unhappy. Imagine for a moment, that it were the case that this were a dangerous situation. Would parking a car beneath the tree help? Would shouting at the people in the tree make things safer somehow? Apparently the cop either does not think the situation is dangerous (in which case it's unclear why he's saying it is), or the cop is not thinking.

After more of his shouting, I hear him decide that he doesn't need Nels's ID and “just wants us out of the tree”. Typical. Trees are in a gray area. They're in public spaces, so they're accessible. But climbing them is “dangerous”. Climbing them with ropes probably makes things appear visually more dangerous. A few years ago the International Tree Climbing Competition was held in Loring Park, Minneapolis. Despite this, one can't climb there today for risk of being charged with the crime of “vegetation molestation”. Because, really, what else could one be charged for?

At this point the police officer drives away. I hook a line into the back of Caiol's harness (remember that haul loop?) and let her back out to the main line where she descends safely to the ground, leaving me alone in tree.

I had been planning to walk out onto a different branch, set up another system, and descend from it. It was an idea I liked because the branch-walk would be easy and the branches appear strong, visible, and uncluttered. The alternative is climbing back up the branch I came in on. And the thing about branch-walking is that it's generally easier in one direction than the other.

Getting back up the branch is not easy.

To climb well requires a certain faith. It's easy enough, when you're on the ground, to begin climbing upwards. But, at the top of the tree, I find it more difficult to transfer my weight off of a branch and onto the rope. The first time I did this, with Bripi, I'd tied a new knot system after climbing farther up into the tree. It turns out that the ascension knot I use has to deform slightly to do its work, before which it slips on the rope. As I began transferring my weight, I could feel the knot moving, but, after a double-check, I had to accept that that was part of what it did. After gingerly letting myself onto it for a foot or two, the knot shaped itself and held.

The guy who called the police is sitting at a table on the far side of the mall, his feet propped up, watching all this, so I disconnect myself from the line and go over to talk to him. He says it looked dangerous and the natural thing to do when you see something dangerous is to call the police; that he's known mountaineers who climbed, until they got crippled.

An aspect of tree climbing, and other endeavours, which I try to keep myself aware of is that incompetence hinders self-assessment. There's a lovely paper entitled Unskilled and Unaware of It which says the following:

People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.

It's humbling to read about this sort of cognitive bias, not just because being aware of it probably doesn't help you avoid it, but also because skill in recognising your inabilities is itself a skill prone to such bias! Ahhhh!

If the man was referring to tree climbing as dangerous in this sense, I'd forgive him; the evidence is, that he is generally correct. But he isn't. In his mind, the activity itself is dangerous enough to require police intervention, regardless of who is doing it. Other such activities include mountaineering… will he next want to ban the mountains? I keep a postcard on my desk. It asks the question, "Do you have enough risks in your life to stay alive?" There's another as well, "Don't take life too seriously… you won't get out of it alive." Or maybe we should refer to the tagline for the movie Braveheart, "Every man dies; not every many truly lives." The point isn't that we should take stupid risks or intentionally put ourselves in harms' way, but that risks are often associated with gains and can lead to satisfaction. The point is to understand risks and take the those you're comfortable with, and some that you aren't. The man talking to me now goes beyond avoiding risks himself, he thinks it is morally permissible to prevent others from taking risks he deems unacceptable, even if he has limited understanding of the situation.

I doubt the mountaineers he "knows" would agree with such a philosophy. But I digress.

I've played a frisbee game similar to the very popular "ultimate frisbee" three times this year. In the first game, I watched two people run directly into each other, the smaller one flying backwards and hitting the ground. Hard. In the second game, I tried to catch a frisbee, and unwittingly redirected it into my eye. In the third game, another player leaped and collided with me in mid-air, doing something odd to my hip. It took four days before I could walk normally again. In four years of rock climbing at the U, I've heard of perhaps two twisted ankles and one shoulder injury among all the people I've climbed with in that time. I don't know if you can relate this to tree climbing, where the worst I've experienced is a few scrapes, but it seems somehow significant that activities we innately think of as "safe", such as frisbee, are not, whereas activities which look "dangerous" have a much higher degree of protection.

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