Fall Colors... in July

The fall colors start on the coast in July. This year, I first noticed poison oak turning red on July 25th. Not a lot, but individual leaves on certain plants. The grass was already yellow, and the smell of mid-summer dust on the trails was in the air.

California Bay are evergreen, however there always seem to be scattered yellow leaves within a tree's canopy, which remind me of Christmas Tree decorations. These yellow leaves seem to fall more in earnest in August, piling up on the ground and on the trails beneath the trees and drifting into mini-debris jams at the riffles in the creek. It doesn't seem like the foliage in the tree looks any different, even though the yellow leaves seem to fall more frequently now than in early summer.

California Buckeye is
a very interesting tree. It is drought deciduous, meaning that it loses its leaves in response to the late-summer drought that California has every year. This year, on August 7th, I saw a buckeye that already had its leaves turning a burnt-brown color. Meanwhile, a couple of hundred yards away in the understory was a buckeye with bright green leaves. The flower spikes on a buckeye are large, and individual flowers open slowly through the season. On that second tree--the one with still green leaves--flowers near the tip of the spike were fully open while capsules were already forming on the lower part of the spike.

On a walk I took on August 29th, the bay leaves on the forest floor were covered by the madrone leaves. Madrone are also evergreen, and by looking at the trees you'd never guess that such a leaf-drop was occurring. Pacific Madrone also have papery peeling bark. Once on a hot summer day near the Yuba River in the Sierra foothills, I could hear the sound of the madrone bark peeling in the heat.

Speaking of "fall", on this day I also saw an oak and a madrone limb that had fallen across the trail. There hadn't been a big wind. This is something called summer limb drop, and it occurs in oaks, eucalyptus, and a few other species in the afternoon (according to the California Tree Failure Report Program) during the summer when the uptake of water by the roots perhaps can't keep up with the evapo-transpiration of water from the leaves. The process isn't fully understood, but large limbs can fail.

August days can be hot, but the nights seem cooler as fall approaches and the days are shorter and the sun glides lower across the sky. This evening at sunset there was a chill in the air reminiscent of fall, and a strong breeze rustled the leaves of the trees. Still three weeks from the autumnal equinox, it really was starting to feel like fall--over a month after the first bright red fall colors danced on the poison oak leaves, while the Tarweed was blooming and Sticky Monkeyflower still held blossoms.