Autumn has officially started and will now be redecorating the Tehachapi Mountains, changing the broadleaf trees and shrubs from assorted shades of green to a variety of yellows, browns, golds and reds.

The longer, colder fall nights bring out the color in both our native and introduced trees. Virginia Creeper, a popular ornamental vine, will soon be a riot of color in Tehachapi, with the more exposed leaves having turned a deep old barn red while the more protected leaves are a dozen different shades of red and the most sheltered are still verdant green. Many cultivars like Red Maples, Liquid Ambers, various birches and others are beginning to change into their autumn clothes as well.

Native plants that can produce glowing fall colors include willows, Black Oaks, Valley Oaks, Fremont Cottonwoods, Chokecherries and California Buckwheat. We don't have the fall color displays of places like New England – our mountains have fewer broadleaf trees and tend to have lots of conifers like White Fir, California Juniper, Jeffrey Pine, Gray Pine and other evergreens whose leaves (needles) don't change color much but stay a shade of green year-round.

Some of the most exquisite fall colors come from an unexpected source: old fruit trees. Apples and especially pears can develop some gorgeous fall colors, and some of the aged trees in remnant orchards turn beautiful shades of yellow, orange and red in October and November. Tehachapi's typical autumn weather of bright sunny days and cold clear nights are perfect for bringing out the colors in fall foliage.

So what makes leaves turn color as the year wanes? During spring and summer as leaves make food for the trees, the abundant chlorophyll they produce keeps leaves green. When the days shorten, however, chlorophyll production stops and as the green fades away, it reveals the yellow-pigmented carotenoids that have always been present in the leaves but have been masked by the chlorophyll.

Carotenoids are responsible for the yellow and orange color of many familiar plants or plant products, including carrots, bananas, corn, daffodils and others. The sugars that remain in the fading leaves, coupled with bright sunshine cause the production of red-pigmented anthocyanins that can turn autumn leaves scarlet, red or even shades of purple. Anthocyanins produce the red colors found in strawberries, grapes, cranberries, red apples, cherries and other fruit.

While the lovely results of these chemical processes are obvious to the eye, botanists still don't know all the purposes or details of the great fall color shift, and a complex combination of factors determines how vivid each autumn's leaf display will be.

The most colorful performances seem to follow a wet spring coupled with a warm summer and crisp fall days with lots of sunshine and cold nights – but not too cold, because hard freezes will cause the leaves to drop early before their full color range has had a chance to develop.

This is looking like one of those years with the perfect conditions, so be watching as the beautiful colors of a Tehachapi autumn develop. Both native and introduced trees and shrubs are being repainted with a fall palette, and they should be experienced before the leaves drift to the ground to nourish the plants that produced them.

Jon Hammond

Virginia Creeper frames the sign at our place on Cherry Lane. The leaves range from green to yellow, pink, red and scarlet in graduating hues.

Jon Hammond is a fourth generation Kern County resident who has photographed and written about the Tehachapi Mountains for 38 years. He lives on a farm his family started in 1921, and is a speaker of Nuwä, the Tehachapi Indian language.