Tree of the Week: Do we need to help nature recover from fires?

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Although the Station Fire is fresh in our minds, it is almost a year since the Sayre fire burned in the Sylmar area last November and a little over two years since the May 2007 Griffith Park fire. Our original native landscape, be it sagebrush, chaparral or woodland, is adapted to periodic fires occurring at intervals of 25 to 100 years and doesn’t need our assistance to recover. As much as we love to help nature, she does quite well on her own. Buried seeds of native annuals and perennials will sprout but, exciting as it is to see wildflowers come up during the first spring and the gradual changes thereafter in the landscape, the recovery of mature brush and perennials will take many years. Even the resident animals will gradually return. Human fire recovery efforts, such as seeding slopes with nonnative grass, have usually done more harm than good.

It is a different story in the natural places we have steadily interfered with or live very close to, the wildland-urban interface, for example, at the edges of the Santa Monica or San Gabriel mountains. Heavy rainfall the first winter may cause the erosion of slopes and trails without leafy branches to break the force of the rain or enough surface roots to hold the slope in place. Wooden retaining structures may have become partially burned and lost their stability. Trees may have become dangerously unstable or be leaning and will have to be cut down to protect hikers. Fires occurring too close together, within a few years of each other, will permanently wipe out native plants. In many places the fires weren’t hot enough to kill the seeds of invasive plants; those sprout first, causing major infestations of obnoxious weeds including black mustard, castor bean, thistles and grasses such as annual ripgut, fountain and Pampas grass. Those weeds will crowd out the native plants. Some of our nonnative garden trees and shrubs also spread their seeds and become post-fire invaders, such as fig, pepper tree, eucalyptus, Mexican fan palm, broom. So should man help nature recover from fire? Yes, but only as appropriate. In some wildland-urban interface areas, once it is safe to go back in, we should judiciously interfere through eradication of weeds, prevention of erosion, restoration of trails and the planting and maintenance of appropriate natives.

Although resources are available to fight fires, there is very little money for preventing the next fire or restoring nature. To find out more, help or volunteer, check out the Safe Landscapes Calendar or any of these websites: northeasttrees.org; angeles.sierraclub.org; treepeople.org; cal-ipc.org.

--Pieter Severynen

Thoughts? Comments?