Fire Safe Almanac – Clearing Fallen Leaves

Post date: Sep 1, 2014 6:12:14 PM

If you've gone walking under the redwoods on one of our recent misty moisty mornings, you've surely noticed how damp it is from the fog drip. Walk into one of our mixed hardwood stands or bushwhack through the chaparral and the ground crackling dry, covered with fallen leaves. This is because these plant communities are largely “drought deciduous”.

While redwoods absorb great amounts of water through their needles, which are shaped so as to drip the water that they can't absorb onto their roots below, mixed hardwood and chaparral community vegetation doesn't absorb the fog and loose even greater amounts of water via transpiration from their leaves. In fact, according to the rate of this evapotranspiration has been the most reliable indicator wildfire danger in the Santa Cruz mountains. Accordingly, hardwood and chaparral species here have adapted to drought by dropping their leaves in the hottest, driest part of the summer, unlike eastern forests which do so in response to cold and shortening days. In this year's historic drought, the effect is particularly dramatic.

Unfortunately, the fallen leaves also accumulate on our decks, roofs, and rain gutters, where they provide a receptive fuel bed for wind-borne embers. As we are now entering peak fire season, it is a great time to sweep your deck, especially where it meets the siding on your house, then (shiver) get out on your roof and remove the leaves there and in the gutters. When you're done, take the broom inside with you – it also acts like tinder in the firebrand blizzard accompanying a wildfire.