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18.12.02

The prospect of effective fire management is daunting. These days most people have accepted that total fire suppression in forests and other environments is neither possible (catastrophic and uncontrollable wildfires will eventually happen) nor desirable (for example, the health of the giant sequoia forests is declining because of fire suppression). But this leaves us with the question of how we ought to burn wild areas. Different management goals require different types of burning. Hazard reduction burning isn't ideal for logging or grazing, for example.

Now, let's say we're a national park, so we can agree our foremost goal in managing the environment is to preserve biodiversity. This still doesn't extricate us from the problem. Different species need different fire regimes. Some would be killed by intense fires, others need that heat to crack open their seed pods. Some need patchiness in order to recolonize burned areas, but unburned patches provide refuges for herbivores that can decimate seedlings. Some prefer to be burned every 3 years, some every 20 years.

The usual tactic is to try to imitate the "natural" fire regime. In some places it has been recognized that "natural" fire regimes haven't existed since the Ice Ages (when the environment was quite different), so there's an effort to resurrect premodern (often indigenous) fire practices. Yet how can any fire practice, no matter how authentic, meet the conflicting requirements I mentioned in the last paragraph?

Part of the answer is, I think, spatial variability. It was possible to favor one species in one area and another in another area -- and shift those favors over time --, and over the long run and the wide extent of the biome, it would all even out. You could burn one area every year and another area every 50 years. You could have giant fires some places and patchy ones other places.

In most areas, that strategy is no longer as viable. Wild areas are chopped up into little chunks, and we're trying to preserve a full cross-section of a biome in each little piece. Different fire regimes can't support each other. We're forced to look for a modernist truth -- one correct answer -- instead of a postmodernist one -- lots of decent answers making up for each others' shortcomings.

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