Sunday, January 06, 2008

Fire in the Garden

A savanna is a mutt of forest and prairie parentage. Acre for acre savannas have more species than their parents, the forests or the prairies, because they have such a mix of species living together. If one compares how much has been lost to how much is currently protected, savannas are the worlds most endangered ecosystem. More so than wetlands. More so than old growth forest. More so even than rainforests.

Like much of southern Michigan, my neighborhood was once a savanna, a savanna with scattered, majestic oak trees. With waves of little bluestem, arrowfeather, and scattered big bluestem. Under the trees there were carpets of blue lupine, black-eyed susan, and bergamot. One common theme of pioneer accounts: it looked like a flower garden, like Eden. Another common theme of pioneer accounts: the savannas burned. Mile upon mile upon mile burned, often annually. And when the fires stopped, the savanna disappeared. Without fire to rejuvenate the grasses and wildflowers, and to prune the small trees back tot he ground, savanna became forest, or crops, or pasture.

Many of the grasses, wildflowers, trees, and shrubs in my garden are savanna plants. They love fire, especially wild blue lupine. I have a propane torch and will burn individual plants, when the setting and weather make it safe to do so. (In the spring I also assist my employer with burning remnant savannas and prairies.)

Today I mimicked fire in the garden. The bed in question is only a few feet from the vinyl siding of my house. We are experiencing an unseasonable thaw (average temperature 32 F, 0 C, today's temperature 50 F, 10 C). I noticed that wet, slimy leaves were lying over the lupine and other savanna plants. Lupine is very sensitive to rot, and most savanna plant seeds will only germinate when exposed to open soil. So I mimicked the effects of a good fire and hand picked the leaves out of the garden. Like a fire, I exposed the soil to the air and (someday) sunlight.

I was just happy for a rare mid-winter chance to get my hands dirty.

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