Aspens near Bishop, California | Photo: Pacheco, some rights reserved Fall is coming, and with it the promise of brightly colored fall foliage. But let's face it: throughout most of California, fall color can be hard to find. Transplanted Easterners nostalgic for the psychedelic red, orange and yellow hues that cover autumn trees in Vermont and Virginia can find themselves at a bit of a loss come fall. Most California trees don't do that.
Its not that there isnt fall color in California. Its just that its not ubiquitous, the way it is in exotic foreign locales like Pennsylvania. Back east, you dont need tips on how to find fall-colored foliage for your viewing pleasure: you basically just need to go outside. Here, you often need to spend a little time thinking about where youre going in order to find those seasonal reds and yellows.
The reason? It's the same thing that brings those transplanted Easterners to California in the first place: our mild weather.
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Back east, deciduous trees have had millions of years to adapt to the pronounced seasonal shifts in that part of the world: warm summers alternating with prolonged, freezing winters.
During the spring and summer, the leaves of Eastern deciduous trees work to turn sunlight into sugar, using the molecule chlorophyll - which gives leaves their green color. Chlorophyll breaks down when exposed to sunlight, so the leaf cells have to replenish it continuously. When those trees decide it's time to start preparing for winter, they shut down the photosynthetic factories in their leaves and stop making new chlorophyll. The remaining chlorophyll breaks down, and the leaves lose their green color.
With some trees, losing their chlorophyll allows the yellow and orange pigments (called xanthophylls and carotinoids, respectively) already present in the leaves to be plainly visible. Those pigments are thought to aid in light absorption to help regulate photosynthesis, and they're there all summer: the chlorophyll just overwhelms them. Once it's gone, the yellow and orange shine through.
If a tree develops red or purple fall color, that means its leaves have turned some of the remaining sugar in the leaves to a class of pigments called anthocyanins, the purpose for which is not well understood.
Whatever palette of pigments the leaves possess, the process is timed to coincide with the onset of the East's relatively harsh winters. California, by contrast, has relatively mild winters due to its Mediterranean climate. Thus many of our native trees don't ever change color. In fact, some of our trees, live oaks being an example, don't lose their leaves in winter at all. Others, like the California buckeye, actually grow new leaves in fall and winter, shedding them with the onset of the dry season in late spring.
But there are exceptions. Some parts of California get colder in the winter, while others may be home to plants whose ancestors evolved the autumn leaf trait somewhere else and brought it here with them as they migrated. And still others are plants we humans imported from other places.
With that science in mind, there are a few basic strategies that would-be leaf-peeping Californians can follow to get their fall color on. The first one involves finding those places in California that have cold winters.
Silver Lake, in Mono County | Photo: Howard Ignatius, some rights reserved
Head for the Mountains
In California's taller mountain ranges, the trees and shrubs are accustomed to much colder winters than their counterparts at sea level. And that means you can often find pockets of brilliant fall color in the mountains. In more humid areas like the west side of the Sierra Nevada, vine maples can offer some of the most brilliant red leaves to be found in California in any season, while their cousins the bigleaf maples provide tall yellow beacons. The same places that harbor vine and bigleaf maples also often host Pacific dogwoods, whose leaves turn a deep wine-red.
Among California's deciduous oaks, the valley oak and the black oak add more yellow to the forest, with an occasional black oak deciding to be a nonconformist and turn red. Blue oaks are more subtle, showing a brief orange tinge as they turn from green to brown.
Farther uphill, aspens can provide a startling display of bright yellow, with entire groves turning the same shade all at once. (That's usually a sign that the aspen stand in question is a clonal colony all descended from the same seed, and connected at the roots.)
The aspens' close cousin the cottonwood turns a similar yellow, and can be found along streamsides and in wet meadows throughout the western foothills of the Sierra, and along rivers in the Central Valley as well.
If you want to spend a few days among the changing leaves, just about any of the trail-equipped rivers and creeks draining the Sierra Nevada's East Side will offer you some aspen leaves, as well as willows and other shrubs that share the leaf-changing habit with their taller cousins. Closer to Los Angeles, the state's southernmost aspen grove is a short day-hike away from the Heart Bar Campground southeast of Big Bear in the San Bernardino Mountains. This grove burned in 2015's Lake Fire, but at last report the resprouted aspens had reached six feet in height, and are no doubt readying themselves to turn yellow. (As the grove is in a recent fire area, check with the San Bernardino National Forest to find about about safety closures, and be sure to obey warning signs if present.)
If you're more of a car potato, cruising the pavement between Lake Arrowhead and Big Bear will likely find you some foliage color. There's also Frazier Park, on the slopes of lofty Mount Pinos; Tehachapi, whose encircling slopes reach around 5,000 feet; Wrightwood and environs in the San Gabrie
