The other night I set out to find "the perfect log" to form the backbone of a new vivarium. It was a beautiful evening with no wind so, with my dog in the bow, and paddle in hand, I eased my canoe onto the lake behind my house to explore the backwater coves that are wonderful nurseries for naturally sculpted driftwood. The serenity of the moment was conducive to letting ones mind slip into philosophical thoughts and it wasn't long before an observation triggered my brain, already ripe for the moment. I glided my canoe toward shore near a promising pile of driftwood and other flotsam. While Kinau chased after unknown scents and collected burrs in his tail, I set about pondering the assemblage of bygone trees, listening for my muse to speak; telling me that this was the log. After a few moments she whispered softly in my ear as my eyes gazed upon the most perfect specimen, split down the middle forming the most inviting bole and intricate texture about its face. There was a problem though. My muse had apparently not measured the 12" diameter glass cylinder that was to contain this monument. This log was fully 30" in diameter and a good 20 feet long. What was I to do? The voice of the muse was speaking louder but even I can figure out that a 20 foot log won't fit in a 24" cylinder. The scientist in me tried to step in, "why don't you subsample?", he said. But I could see no way to slice this log into suitable proportions without destroying the very characters that drew me to it to begin with. And then the answer flashed as a word before my face, like a flashbulb burning into my retina... FRACTAL. Huh? Yes, fractals were the answer. In fact, as I thought about it more, I began to realize that fractals are fundamental to making vivarium design possible.

So what the heck is a fractal? Fractals are organizations of structure that are self similar at multiple scales. A tree is the poster child of a fractal. Your typical tree has a characteristic shape that starts with a trunk and branches into progressively smaller branches and twigs. Cut off one of the main branches and jam the base into the ground and what does it look like? A smaller version of the whole tree. Cut off a smaller twig and do the same and you get yet a smaller version of the whole tree. Mathematically, fractals live between the ordered world of geometry and the unordered world of chaos. Consider a geometric shape like a square or circle. You can describe everything about those shapes with simple formulas. With these formulas you can also predict the shape, location, and other properties of every component of the structure with 100% accuracy. A fractal structure is more complex. The structure has organization, but the rules or processes that govern that organization are so complex that you cannot reliably predict the final structure. Consider the tree again for example. Trees have a fairly consistent branching angle which creates that self similarity as you move from large to small branches. But think of all the things that can affect the placement, direction, girth and length of the branches. Sun, wind, rain, soil, insects, disease, chainsaws.... well, you get the picture.

So what do fractals have to do with vivarium design? Well... everything. What is a vivarium? Is it a miniaturized version of nature? I hope not. Those vivaria that are, present animals that are out of scale with their surroundings and they end up looking like dinosaurs in a Lilliputian world. So, are vivaria vignettes of nature? Well, not exactly that either. Vivaria tend to condense elements from nature into a tighter space by shrinking distances between natural elements. A vignette would be akin to plunking an aquarium sized cube around a selected point in nature. With some exceptions, few 1 meter cubes of space in nature contain the variety and arrangement we cram into our little boxes. A carpet of moss in the forest might occupy 10's or 100's of square meters. How many 1 m. cubes would it take to enclose a tree? It's not that the small spaces in nature aren't interesting, but when we visit natural areas, we simultaneously process sensory input collected from a relatively large volume of space. These inputs coalesce to form what we perceive as "the experience". A vivarium seeks to provide the same type of experience through largely visual cues gathered from a much smaller space. That's why we tend to put a water feature on the ground and epiphytes in the air much closer together than they would typically be found in nature. It works, but why? You guessed it, fractals! Because of the fractal nature of nature, you can use softball sized rocks to get the same effect as house sized boulders. The small rocks have the same level of detail as the large boulders. By changing the scale, you do not lose anything in texture, color, or shape. It is perfectly self similar. If it were not, the small rock would look nothing like a large boulder and anything that did look like a scaled down version of the boulder would create the Lilliputian effect we seek to avoid. This doesn't happen because scaled down versions of boulders are everywhere in nature so they look quite at home in vivaria without imposing an artificial scale. The same is true of bark, branches, roots and water features. Fractals allow us to scale down the elements of nature so they can be arranged aesthetically in our little boxes without turning the animals into a sci-fi show.

Following this little nerdworld epiphany, I committed the features of the monument to memory and bade goodbye to my goliath friend, whistled for the dog, and once again plied my paddle to the water. Thanks to fractals, I knew there was a smaller log built on the same theme as my oversized model waiting for me somewhere. As it turned out, it was a better night for paddling than log hunting. I hauled my canoe to shore at twilight. A heron croaked as it winged toward it's roost, a fish broke the glassy surface of the water, the dog chased his tail, and a fat, full, moon rose over the rarest ecosystem in North America. Life is sweet.