8/7/2019 Eastern Sierra Fall Color Guide

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Every autumn, cottonwood, quakingaspen and willow are transformed intocolorful hues of gold, orange and russet.

Before long, their leaves will fall and againbecome part of another cycle that feeds thesoil. What causes this yearly cycle, and whatdetermines which color the leaves turn?

During spring and summer, leavesactively produce foods necessary for plantgrowth. This food-making process takesplace in the numerous cells within the leaf.Within these cells are Chloroplasts, whichcontain the chlorophyll pigments that areresponsible for the green color of plants.

The leaves also contain lesser amounts ofother pigments, primarily xanthophylls(yellows) and carotenoids (yellows, orangesand reds).

Most of the year, these other pigmentsare masked by the greater amounts ofchlorophyll present in the leaves. But infall, when changes in temperature and theperiod of daylight occur, the leaves stoptheir food-producing activity. Soon thechlorophyll begins to break down, thegreen color disappears, and the yellows,oranges and reds slowly begin to emerge,giving the leaves their fall splendor.

The intensity of color is determined bythe plants response to complex gradientsof temperature and moisture. Fall weatherconditions favoring formation of brilliantautumn color are warm, sunny days followedby cool nights with temperatures below45F (7C). Sugar production increasesduring the daytime, but cool nights prevent

movement of sugar from the leaves. Fromthe sugars trapped in leaves, the red pigmentcalled anthocyanin is formed. When fallweather is consistently cloudy or rainy, andthe nights warm, the leaves usually haveless intense coloration. The smaller amountsof sugar made during periods of less sunlightmoves out of the leaves during the warmnights, reducing the conversion of excesssugars into pigments.

Before the leaves gracefully spin fromtheir leafstalk, a special layer of cells devel-ops and gradually severs the tissues thatsupport the leaf. A small leaf scar is theonly evidence that leaves once adornedthese deciduous plants.

Anne Halford, BotanistBureau of Land Management,Bishop Resource Office

Why do leavesturn color?

FALLCOLORG U I D E

E A S T E R N H I G H S I E R R A

C A L I F O R N I A

BishopAreaChamberofCommerceandVisitorsBureau

690N.MainStreet,Bishop,CA93514

CountyofInyo

P.O.DrawerN,Independence,CA93526

MammothLakesTourism

andRecreationDepa

rtment

P.O.Box48,MammothLakes,CA93546

MonoCountyTourism

andFilm

Commission

P.O.Box603,MammothLakes,CA93546

The Eastern Sierra region is laced with rugged canyons carved by rushing streams, and home to some of thefinest fall color viewing anywhere. Autumn displays of golden aspen mingle with pine forest and contrast withstark granite walls. Cottonwood and willow line stream banks and border alpine meadows. Above it all looms

the towering Sierra Nevada mountain range jutting into the azure sky.The trees generally begin their annual color show in mid-September and, depending on Mother Nature and

elevation, can extend into late October. Warm days and cool evenings mark this time of year in the region, makingit not only perfect for viewing and photographing the fall splendor, but also taking part in the many recreationalactivities and events the entire Eastern Sierra region is famous for.

A wide choice of accommodations and dining opportunities completes the picture.The Eastern Sierra in the falla special time in a special place.

Certno.SCS-COC-1158

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