Saturday, May 14, 2011

Fire and the Beauty of Destruction

Der gefesselte Prometheus by Jacob Jordaens, ca. 1640

As punishment for stealing fire and gifting it to mortals, Zeus had Prometheus bound to a rock while a great eagle ate his liver each day only to have it grow back again for the next.  Little did Prometheus know what a powerful and destructive force he had gifted to mankind.  Our dance with fire extends far back into our history: the estimates for the earliest definitive evidence of control of fire by a member of the genus Homo range from 0.2 to 1.7 million years ago.  Fire is a tool that defines us as humans, no other animals can control it as we do, although our close relatives, the chimpanzees, understand wildfires well enough to monitor them and to safely guide their movements.  However, humans are unique in their ability to use fire to cook food, create warmth and protection, and to shape their environment.

As a student of plant ecology, the role of fire in shaping plant communities has fascinated me.  Contrary to the impression one may get from learning about fire ecology solely from "Smokey the Bear" PSAs, pyrogenic plant communities exist all over the world; to my knowledge on every continent except perhaps Antarctica.  That is not to say that you should wantonly toss matches out of your window while touring the pine barrens here in the northeast, for the intensity and frequency of fires needs to be controlled for the maintenance of certain plant communities, and some more than others require for this to be quite the delicate balancing act.  However, certain species require fire in order to prevent being out competed by less fire tolerant species.  In the pine barrens, for example, without fire the barrens will proceed through seral stages, eventually resulting in a (probably oak-hickory) climax forest.  Without periodically burned habitats in which to grow and reproduce, these fire dependent plant species would go extinct.  These pyrogenic plant communities are not at all rare either, look at this map of prescribed burn intervals across the continental United States:

Many plants have evolved traits that not only allow them to survive through or reproduce after a fire, but some actually can encourage the fires that sustain their existence.  The Australian plant genus Eucalyptus is especially notorious for its flammability: the concentration of volatile oils such as Eucalyptol in vegetative parts is high enough in some species as to make the plants literally explosive.  Plants that display fire-mediated serotiny, where seeds are only released after fire, can only reproduce after a fire; in the United States, this trait is especially common among conifers such as the pines.  The evolution of many of these fire dependent plants has been to a large part encouraged and guided by the use of fire by man.  

This should make Smokey cringe - An Australian Aboriginal fire stick

Man recognized quite early on this power fire held for shaping the environment.  Many of the grassland and other pyrogenic plant communities around the world were spread and evolved under the pressure of regular burning by indigenous societies.  Many early hunter-gatherers were effectively ecosystem engineers: they recognized that fire could be used to clear forest and create open grasslands which were perfect for hunting, and they used fires to guide the movements of animals into these open areas.  Later, tropical agriculturists recognized the utility in using fire to clear dense tropical vegetation and release plant nutrients into the soil, pioneering the swidden or 'slash-and-burn' systems of agriculture.  The Australian Aborigines are especially renown for their use of fire, living as so called domiculturists - in a way domesticating their environment with management tools, such as fire, in order to increase the availability of edible plants to gather and game to hunt.

Wildfires are reported in media outlets often solely in negative terms: ie. in quantities of human life lost or economic damage.  But never does one hear of the role fire plays in sustaining life.  Without periodic destruction by burning, many beautiful and diverse ecosystems would decline, slowly being succeeded by fire intolerant communities.  Besides, many of the horrors of wildfires are only a result of human ignorance of the intrinsic reliance on fire of so much of the world's flora: when one builds a human settlement in the middle of Eucalyptus forests and suppresses fires while fuel loads build up, what can one expect but the occurrence of colossal wildfires such as the Black Saturday Bushfires in Victoria, Australia?  Wildfires are not necessarily something to be feared, unless you have been so unwise as to make your residence amidst a fire-prone region.  Instead, fire's ability to create life should be fully embraced.  We should learn from our relatives, the chimpanzees, who do not panic at the sight of fire, but calmly observe its effects and evade its destructive path.


  1. This is a fantastic exploration of violence as it relates to creation or continuation of life. Lots of mushrooms are also pyrogenic, and there's a whole culture of mycologists who love forest fires so that they can stalk through the ashes for black morels. Although with mushrooms, especially the black morel, I'm not sure if we've figured out what their actual relationship to fire is, only that after a fire, there are lots.

  2. As a fanatical mycophage myself, I'm surprised that I failed to mention fungi - although the role of fungi and other decomposers in the cycle of life is worthy of its own treatment. The lifecycle of the morel is not yet quite worked out, although Tom Volk and others have done some excellent work on ironing out the kinks in our knowledge:

    As far as relation of morel to fire goes, here is how I understand it: the morel fungus lives hidden from site underground in its hyphal stage as either a saprophage (consumer of dead organic matter) or mycorrhizae (symbiotically with tree roots) (not sure if this is worked out yet, and it can certainly be a bit of both). If they are mycorrhizal, which their close distributional association with trees suggests, when fire kills the tree host the morel mycelium no longer has a food source, and it will fruit (producing an ascocarp - morels, as members of the Ascomycota, do not technically produce "mushrooms," which are characteristic of the Basidiomycetes, a phylum containing the gilled mushrooms among others), allowing it to disperse spores to colonize new lands or tree roots.

    As a side note, the morel season in Ithaca is officially on, as Kathy Hodge has announced that someone has claimed Cornell's "First Morel Contest" (though the website doesn't seem to have been updated with the new winners):

  3. On second thought, what I replied may not be "technically" correct either as I'm pretty sure that not all Basidiomycetes produce mushrooms - to my knowledge, no one refers to the fruiting structures of a wheat rust as such, for example. Of course, like the fruit or vegetable status debate over tomatos, it all depends on your point of view. Culinary classification is every bit as valid as mycological taxonomy.

  4. My father deeply relies on controlled burnings to protect his pine forest every year. Often the summers are dry without hurricanes and fire watches are a popular occurrence. If controlled fires are not handled early in the summer, the chances of a fire sweeping through are relatively high. Sometimes the best way to fight fire is with fire.


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