There’s no one simple answer as to why the rainforest is so diverse; keen minds have worked hard at the problem. For example, why are so many different species of trees found in the tropics? One answer: pests at work. In an environment without the seasonal variation of the temperate zone, i.e., no freezing weather, insects, parasites, fungus and disease aren’t knocked back every year as they are in the north. A grove of trees of the same species would be vulnerable in the tropics; there is no safety in numbers here. Better to disperse your seeds widely and keep your species on the rare side. Your pests won’t prosper if you space things out- they’ll be spending their time tracking you down. Maybe they won’t find you at all.
Fruits designed to ride the wind or seduce animals into eating them and dispersing their seeds testify to the urgency of removing seeds far from their parent plant and the specialist pests living on it. The more nearly everwet a tropical forest’s climate, and the more evenly year-round its pest pressure, the higher the proportion of tree species therein that employ animals to disperse their seeds.—Egbert Leigh, Jr., A Magic Web: The Tropical Forest of Barro Colorado Island
Last night I made a printout of my orchid drawn on Barro Colorado Island and enlarged it onto a big sheet of Rives BFK measuring 27″ x 35″, using an overhead projector. Standing up to draw at the top of the paper, then sitting down as I drew the middle, and finally kneeling on a cushion to draw close to the floor, I tried to duplicate every sketchy gesture and scribble from the field drawing onto the enlargement. It took about four hours and an entire fatboy graphite pencil start to finish.
Because I like toned paper and Rives only makes this size in white, I decided to tone it myself. After some thought, I decided to soak the Rives and drop diluted acrylics onto the wet paper, letting it bloom randomly and drool and drip its way down the tilted sheet. Before doing this to my hard-won drawing, though, I practiced on scrap paper and in the computer, making a color map to follow.
Soaking the paper meant going outside and turning on the garden hose. I had everything ready nearby: yogurt containers full of diluted colors (purple, ultramarine blue, and a warm cinnamon mix of diarylide yellow, transparent burnt sienna and napthol crimson), a clean scooper (from a laundry detergent box) for pouring out the paint; paper towels, a wide brush, a bucket of clean water, and my color map were at hand. Finally, a wooden board big enough to hold the big sheet of paper, and a staple gun to stick it there.
I was going to have to work fast- a storm was brewing to the west and the wind was coming up. I didn’t want to risk raindrops in the drying paint.
Dynamic complexity is a way of describing the entanglement of interacting components in a system. I think it’s also a perfect description of what a rainforest looks like. The entanglements are visually rich and the interacting components are just pure eye candy. Diversity made possible by pests- what a beautiful system!