The Arbornaut, page 8
My advisor was right to send me into the bush before I finalized any research plans; this first trip allowed me to set lofty yet realistic goals. And now I wanted to be up high with those millions of green machines (aka leaves) taking in sunlight. I returned to the botany library and eagerly read about how forest scientists had accessed tropical trees in other parts of the world (mostly cutting them down, I soon learned), and attended seminars to hear other students explain how they selected field sites (they all made it sound so easy). Immersing myself in the collections of the University of Sydney herbarium, I learned the fundamentals of identifying rain forest trees, although most specimens were restricted to just understory leaves in a two-dimensional state of brown, squished, and dry. Names flooded my brain after poring over hundreds of pressed plants, including genera I could hardly pronounce: Acmena, Doryphora, Dendrocnide, Elaeocarpus, Sloanea, Orites, and a major tongue twister, Pseudoweinmannia. I furiously wrote notes and started a series of notebooks on tree species, geographic locations, and field methods. I tried to give myself a crash course on Australian rain forest ecology, but next to nothing was published, and absolutely zero about the canopy or its leaves. Existing scientific publications in other tropical regions were similarly limited to the understory or, in a few cases, based on a fallen tree. Could I ever develop a worthy methodology to study rain forest leaves of the whole tree, which I now realized extended over a hundred feet high? How could I select which of hundreds of tree species to study, what geographic locations, for how long, and how many? There just was not enough existing literature or advice to help me narrow the focus.
I made friends with some graduate students in the marine biology department, who were a veritable gold mine of information and advice for designing fieldwork, although in their case for either intertidal populations of barnacles and their predators, or coral reefs with all their complex ecology. In particular, the coral reef students faced similar challenges of trying to narrow their field research amid a huge array of biodiversity. Like me, they were tempted to do too much. Unlike laboratory studies, where theoretical questions were often answered using one or two species in a cocoon of controlled conditions, field biology was fraught with obstacles: weather, floods, tree falls, bugs, drought, fire, edge effects, human activities, and sampling bias, as well as some factors that I forgot to consider. I probably should have received an honorary degree in barnacle population dynamics or butterfly fish ecology given the hours I devoted to assisting fellow students with their research. But our many discussions enabled me to design fieldwork more accurately and efficiently in the trees. Monitoring tropical fish in the three-dimensional habitat of a coral reef was not too much different from observing insects in a three-dimensional tree crown, except instead of tidal currents and sharks, I had the challenge of gravity and snakes. On top of everything else, as the only rain forest ecology graduate student and one of two females out of approximately twenty-five students, I needed to succeed in a male-dominated, marine-centric workplace. Fortunately, I met some wonderful male graduate friends and probably received more (not less) attention as the only student focused on rain forests. As a case in point, I met Hugh at the photocopy machine one Friday afternoon, where each of us was furiously making copies of the latest article by the world-famous ecologist Joe Connell, from the University of California, Santa Barbara, who studied species diversity in coral reefs and tropical forests. Hugh saw me clutching a copy of The New Yorker magazine and smiled. A New Yorker subscriber himself, he already knew that only one hundred subscriptions existed in Australia, which he commented made us both special. We spent the better part of the weekend discussing the Janzen-Connell hypothesis, a subject that inspired many of our fellow students to test hypotheses about biodiversity. Connell had established long-term plots in coral reef patches and on rain forest floors in Australia; over time, he monitored the success of each species, ascertaining important information that competition in higher diversity ecosystems actually sustains the system, rather than driving it toward single-species dominance. Both Hugh and I were extremely interested in diversity, particularly as it might impact the health of different intertidal ecosystems or rain forest trees, respectively. Hugh studied the seasonality and competition of barnacles along the New South Wales coastline. He transplanted different species of barnacles on artificial plates but carried out his work in the field with waves crashing all around him, almost unheard of, but successful in terms of results. Such chance interactions during those halcyon days of genuine intellectual inquiry were the stuff that made graduate school one of the best chapters of my life.
As I chattered with greatest animation to Hugh and other students over those first weeks, I began to crystallize research questions and field protocols for Australia’s tall rain forests. So when that much-admired American ecologist actually showed up at Sydney University to give a seminar on his innovative research about species diversity, he asked if anyone was working on rain forests. Only one hand shot up. He needed a field assistant to identify his trees and seedlings, so I instantly had the job—no competition. I was walking on air at the prospect of working with this distinguished scientist, and ultimately our partnership lasted well over a decade. Like me, Joe Connell had worked in Scotland and now shifted his field research to Australia. For many years, he mentored me, and even gave me the ultimate nickname, Margaret Number 2 (his wife was Margaret Number 1), because we shared so many adventures and thousands of hours identifying seedlings and trees. (Someday, I may write another book on giving blood to leeches as we “groveled”—Joe’s pet term for our field behavior—on the forest floor marking thousands of seedlings … I sometimes refer to such ground-based research as my retirement plan for when I can no longer climb.)
My prior experience with temperate leaves inspired some of my first questions about tropical foliage: What triggered these leaves to fall in the absence of cold winters? How did the ones at the bottom of the tree survive in such low light? And what about the uppermost foliage in that hot, relentless sun? These questions evolved into a thesis plan: to observe leaves emerge, grow, and die. (I secretly hoped it would be simple.) Compared to the seasonality of wildflowers and trees in upstate New York, where everything shut down like clockwork after the first autumn frost, I needed to watch for other cues that triggered the end of a tropical leaf’s life. All living things, evergreen leaves included, have a finite lifespan, defined by physical and biological factors. From reading, I knew most tropical trees were evergreen, meaning their leaves didn’t fall all at once, but only some at a time, and so I hypothesized that leaf emergence similarly occurred throughout the year, without any well-defined season. It seemed pretty logical. Given the sauna conditions of a rain forest, I also figured a flimsy leaf couldn’t last too long, flailing on the end of a delicate petiole in such a sultry environment with frequent monsoon blasts. So I took a wild guess that two years was as long as rain forest leaves lasted. The hypothesis I planned to test was simple: evergreen leaves emerge throughout the entire year, but each has an average lifespan of two years. Next, I needed to design field methods to challenge the assumption. I imagined myself lounging in a jungle hammock in a beautiful tropical setting, watching leaves fall over the course of several years, and then writing up a dissertation. But when I casually proposed this scenario to my advisor, he chuckled politely. He liked the hypothesis about leaf longevity but wasn’t convinced I should passively record leaf fall as an observer on the forest floor. He suggested any worthwhile fieldwork required scaling the trees to examine the leaves where they grew. I was not athletically inclined so first proposed a few ground-based options that indirectly embraced the canopy region: I could train a monkey? Use super-powerful binoculars? Sit on a ridge alongside a gulley adjacent to some upper crowns? Use a shotgun to bring leaves to the ground? No, my advisor explained, if you want to study the leaves, then you need to access the whole tree, not just the understory. And if you want to study their lifespan, then you need them to stay attached to the tree. As an expert on dry vegetation, especially gum trees that often averaged around ten yards high, he had no arboreal skills to share and seemed blissfully unaware of the height of some of these rain forest giants. Although not a rain forest expert, he was the only botanist at the university who studied trees. True to his function, my advisor gently directed my enthusiasm into a solid hypothesis served by reliable methods to collect accurate data. He forced me to think creatively about fieldwork—starting with a clear hypothesis, and then working backward to establish how I could gather accurate data to test it. First, I wanted to study the leaves. Second, if I was going to monitor leaf growth in tall trees, I’d need to scale them—frequently. The problem was obvious. I just needed some strategies to reach those aerial subjects. By serendipity, I had already found the university caving club for advice and equipment.
My introduction to spelunking came during my first month at Sydney University. Funding was available for ecology graduate students to attend a conference in New Zealand. As the lone rain forest student, I was lumped into the scholarship pool with all the marine students. Mike, the American graduate student who had met my flight arriving into Sydney, proposed we could rent a car and see a bit of New Zealand after the meeting. At the conference, I was all ears to hear how different researchers set up their fieldwork, ranging from mapping kelp beds to counting coral reef fishes and trawling for tiny phytoplankton in the water column. I sat spellbound in the audience, daydreaming about my own experimental design and how to sample in an aerial three-dimensional space, instead of a watery one. After the meetings, Mike and I were supposed to meet up for departure in our rental car, but he was nowhere to be seen. I asked a few others, who chuckled and said, “Try room 122.” It turns out he had met a girl at the final banquet, and they hit it off. When I politely knocked on the motel room door, he awkwardly threw me the car keys and said, “See New Zealand on your own.” Suddenly, I was exploring a new country as a solo venture. I was fine driving on the left side of the road, having adjusted in Scotland, but a little apprehensive about camping alone in strange settings. However, not only did I hike alone in Tongariro National Park and camp near a hot spring, but I also stopped to see the notorious luminescent glowworms at the Waitomo Caves. By chance, I ran into the park manager, and we traded credentials. He was about to lead a caving adventure to find ancient moa bones, a flightless bird that became extinct around the year 1300 due to hunting by the Maoris. He invited me to participate, saying more eyes were an asset to their nocturnal quest. I was not a speleologist, but it still sounded like fun. After donning a helmet and taking a quick one-hour lesson in harnesses and descending on ropes, off I went for an all-night caving expedition. I don’t remember much about the actual descent because I was terrified in the dark. But we found lots of bones at the bottom of the cave, and this introduction to a vertical transect on ropes came in very handy a few months later as a neophyte arbornaut.
After spelunking in New Zealand, I sought out the cavers at Sydney University, who laughed at the notion of climbing up given they always climbed down. But they realized I had a serious determination to reach the treetops. Fortunately for me, the Waitomo Caves experience gave me confidence that caving equipment might be adaptable to the needs of an arbornaut. Arborists, those stalwart tree climbers who prune and cut urban trees, use a completely different outfit composed of heavy-duty gear suited for overpowering the branches and crashing through the tree crowns; their gear would not help me navigate a tree delicately, keeping every leaf intact. But cavers used lighter gear, conducive for carrying many miles on remote trails to access underground exploration and often worn all day on a long expedition. The Sydney University caving club made their own gear since no commercial recreational equipment was available in those days. One of the only female members, Julia, loaned me her industrial sewing machine plus a length of bright-orange webbing (probably obtained from a military supplier, since car seat belts were not yet available), so I measured my waist and thighs and copied their design to sew a basic harness. I never imagined I’d be grateful for my seventh-grade home economics class, where I became an expert operator of the original Singer zigzag sewing machine and had even mastered the art of making an entire pantsuit, including a zipper. By comparison, making a climbing harness was much simpler. But in addition to a harness, I still needed some technical hardware, so Julia’s caving partner, Al, kindly sold me two jumars (toothed metal devices for upward ascent on a rope), a few carabiners (metal climbing clips) to connect ropes and hardware, and a whale’s tail, which was a metal rack with four holes to thread the rope, thereby slowing my speed of descent. This was the perfect gadget for a leaf lover since I would never come crashing downward. I was also inwardly quite scared about dangling from a rope on a branch of unknown strength, so any hardware that slowed me down or provided extra control was much appreciated. Al also taught me to tie a few essential knots, including the climber’s all-time favorite Prusik knot and the highly secure clove hitch. Fortunately, many of them stayed affixed to the gear so never needed to be retied. Last but most important, I needed a climbing rope that had to be more than twice the length of the highest climb, so the rope could be placed up, over, and back down from the highest secure branch. With just over two hundred feet of rope, I would be able to climb any tree approximately one hundred feet high, leaving enough extra length to tie off around a nearby tree trunk at ground level. Based on eye estimates from initial visits, I figured this was a good height for starters. I also bought a bicycle helmet, bright orange to match my carrot-colored harness.
But how would I rig the rope in the upper branches? Cavers simply drop lines down into a dark hole; their biggest hurdle is a lack of light for navigation. But I had to get my rope to literally fly, so I needed a slingshot, the only gadget that could propel a rope and also be used safely by a neophyte like myself. I soon discovered they were illegal to purchase in Australia, so I would have to make one. Most field biology students are constantly rigging gear, like metal frames for fish counts or special cages to capture small mammals, so I had already befriended the staff at the university workshop. A gray-haired veteran of gadgets named Basil helped me find a metal rod of the perfect diameter, and together we welded it into a classic Y-shaped catapult and cut a piece of old car tire rubber for the elastic. Then I tied a fish sinker to a reel of fishline and fired a first shot over a fifty-foot-high branch outside of the botany building. It worked. Out in the rain forest a week later, it was a different story. All the vines and dead branches in the tree crowns intercepted the fishline’s trajectory on more occasions than not. Practice, practice, practice! Over time, I became the Botany Department’s version of Tarzan’s Jane (not good ol’ Deadeye Dick) and learned to locate a solid branch with clear airspace beneath, which allowed for vertical ascent up the rope. In addition to the branch and the airspace, my vertical rope transects needed to pass through foliage at different heights that would be conducive for sampling. The process of finding the correct tree species, a safe canopy branch, and also access to leaves along the rope’s pathway was a new skill set I needed to master in the forest, both quickly and safely.
After identifying a limb in the desired species of tree with the right amount of foliage distributed, I was ready to use my newfound slingshot. Rigging the climbing rope was a three-step process: first, propel a fishline via slingshot; second, attach the fishline to a nylon cord and haul it over the same pathway; and third, hoist a heavier climbing rope into place by tying it to the nylon cord, pulling it up and over the support branch. Once the climbing rope is in place, one end is used by the arbornaut and the other is tied off to an adjacent tree. Voilà! A vertical transect through the canopy is ready for access. Over the next few months, I refined my field gear through trial and error. I created a mold for melting lead, to make ideal weights shaped to propel a fishline through dense vines, and I adjusted the elastic slingshot bands to exactly the right length and width for shooting prowess. I also fabricated a special waist belt to hold gadgets—pencils, notepad, waterproof markers to label leaves, duct tape to mark branches, camera, and Oreo cookies for survival. And finally, I designed a hat with face mesh to block sweat bees and other swarming critters while I dangled for long periods of time. I did not tinker with the harness, even though it really dug into my butt, because I was too impatient to get into the trees. Looking back, I realize that I valued precise science a whole lot more than personal comfort. The harness, slingshot, metal climbing hardware, and ropes all fit into one duffel bag and soon became all I needed to access almost any treetop around the globe. The final, and perhaps most critical, ingredient for my toolkit was accessing a lot of inner courage I never knew I had, which only became known to me, literally, on the rope. And so that was how I found myself dangling in a coachwood tree as a neophyte arbornaut, cautiously climbing into the upper crown to discover a cacophony of biodiversity. Much to my surprise, many fellow graduate students (all male) wanted to accompany me into the field to rig trees, because the slingshot was such a fun gadget. Some shooters were successful on the first shot, whereas others took many expletives to get a line over the correct branch. There were no handbooks on climbing, at least none in Australia; there was only the caving club for advice. But if I could safely reach leaves throughout the whole tree, then my challenging research questions could be answered.
