Monday, July 2, 2012

Evotour, Part Six. Fire and Renewal in the California Mountains

Cuyamaca Rancho State Park in California used to have meadows surrounded by pines and black oaks. The pines and oaks extended partway up Stonewall Peak. But in 2003, a fire burned the entire area except some places around the meadow. Today, that meadow is the only place you can find pines and black oaks.

However, the chaparral shrubs have grown back profusely. I am accustomed to dry chaparral that consists mostly of dead sticks, but this chaparral was filled with fresh green stems, flowers, and fruits. Along with the profuse regrowth of manzanita, ceanothus, scrub oaks, and holly-leaved cherry, there were perennial wildflowers in full bloom: penstemon and yerba santa. The shrubs had grown over three meters tall and state park personnel, the few that remain after budget cuts, have to keep trimming them away from the trail. A few of the black oaks have resprouted, and a few pine seedlings have been replanted.

This is a theme I have presented before, but I enjoy being reminded of it when I see it again in the natural world. Ecological disturbances, such as fires, are disasters for the organisms killed by them, but act as a source of renewal for the ecosystem as a whole. Dead grass and wood are transformed into fertilizer that feeds the vigorous growth of new plants, either resprouts or seedlings. The chaparral in Cuyamaca, and the tallgrass prairie of the Midwest, depend on a fire cycle.

I do not doubt that my hike at Cuyamaca would have been prettier if the pines and black oaks had been intact, but I would not have seen the way organisms capitalize on natural disturbances as an opportunity for renewal.

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