Few trees in New York City grow with more vigor and tencaity than the Ailanthus Tree. Commonly called the “tree of heaven”, it has gained the nickname “tree of hell” for its foul odor and tendency to re-sprout after being cut down.

Magicians of the city prize the Ailanthus for these very reasons. Wizards find that the sap of the Ailanthus, collected properly, will double the potency of many potions; sorcerers are able to draw on the tree to gain strength. Shamans cling to the Ailanthus when they wish to contact spirits that would be otherwise too powerful to withstand. The Ailanthus is a testament to the tenacity and resilience of living beings. Modern people living outside the city may expect an urban landscape to be completely concrete and asphalt. But there is the Ailanthus tree, its roots sunk deep into whatever purchase it can get, its presence known long before it is seen. Seriously. It smells like the Devil's wet dog farted.

Not all life is pretty, after all, and many of the things that grow vigorously are decidedly un-pretty, as we judge them. Think of a spider's egg sac releasing its contents, for example, or Black Mold. Yech.

But the Ailanthus is one of the few living things I know that can shift straight into the other extreme.

See, some of the creatures that ARE pretty have their bright colors as an obvious warning sign. "Don't touch", the pretty colors say, "you will regret this." Like the Blue-Ringed octopus. Those rings are a beautiful blue, and the bite of the octopus kills. The bright colors probably evolved because bright colors are more obvious than dull ones, the way people sometimes add flashing lights to stop signs. The smart ones survive, the dumbs ones don't, and pretty soon everyone is avoiding the bright colors. The animals learn the hard way on the level of the whole speices.

I learned the hard way all on my own.

On certain nights, when there's a temperature inversion and all the noise and heat of the city are prevented from escaping to the sky, the trees light up. Nice to look at, and they smell strongly of ozone, for once, instead of roast garbage. Almost clean, in comparison. You can pretend you're in a nice busy office where the copier has been working all day.

One night, as I was fanning myself and failing to do my schoolwork, I looked out the window and saw the tell-tale blue glow of the Ailanthus. I figured, hey, why not go out out and see what the blue swirls of energy are that move out a few inches from the trunk? Almost like a solar flare. I went out to the tree and tried to position my hand so that the energy would play over it.

My fingers accidentally brushed a twig.

In that instant, my ears were filled with the crash of metal on stone, the honking of myriad horns, the scolding of thousands of worried lovers, the yowl of hundreds of cats, and the wail of dozens of police sirens and fire trucks, while my nose was filled with the stench of the landfill, and agaony shot through my thighs, abdomen, and shoulders, as if I was holding a load above my head that my muscles would never allow me to lift. I staggered under the weight, and I must have stopped touching the twig, because all the sensations vanished, leaving me gasping.

On the one hand, the city now seemed positively quiet in comparison. On the other hand, how many people had stumbled onto this already? Here I was trying to learn about the city, and not a single person has mentioned how dangerous the Ailanthus could be.

Then again, maybe that was because nobody was left to report this phenomenon.

I surmise that on nights when the trees glow blue, it's because they're acting as emergency heat sinks, so to speak, for the living energies of the city. There's just too much there otherwise to deal with. Were the Ailanthus not around to absorb some of the energy, who knows? Maybe meek little wives would carve up their husbands while every glass of beer at a cocktail lounge would turn into top-shelf bourbon and everyone inside would have a bar fight.

In any case, things that are extremely pretty are extremely dangerous, brightly-colored wildlife, and Ailanthus trees. It's also true of men and women, but for more complicated, human reasons. That's a story I'll tell when I'm good and ready.