FALLING FOR THE WEST : If New England’s too far and too expensive, here’s where to find the most colorful foliage in nearby Western states.

It’s a chemical thing. Autumn rolls around, the days and nights get cooler, and among trees, shrubs and bushes--from the American elm to witch hazel--photosynthesis slows down. Beeches go yellow. Oaks go orange. Great swaths of New England are festooned in hues from burnt sienna to umber. And in an only slightly less direct reaction, the innkeepers hang out their “no vacancy” signs.

As tourism-friendly natural phenomena go, it’s hard to beat fall foliage. There’s no admission charge, and it doesn’t demand much in the way of physical exertion. But in this tight-money year, not everyone is inclined to beat a 3,000-mile-long path to New England. This could be the autumn to appreciate foliage closer to home.

“I’m from Maine . . . and I think it’s beautiful out here,” said Pat Forrest, a volunteer coordinator for the Napa Valley Conference and Visitors Bureau. “I can’t imagine anybody spending the money to go East for foliage when we have it here.”

In Bishop, meanwhile, Jan Sutton of the chamber of commerce the other day found herself amid “a lot of oranges. It’s really gorgeous.”

Throughout the West, the options are various. Travelers can take the scenery in from the driver’s seat of their cars, climb into the back of a Jeep or horse-drawn carriage, or set out on foot. The leaves may not dazzle in the quantities that New England’s do, but they are here, and for the next month or so, they’re on display.

“The poison oak is looking beautiful right now--a nice, deep red,” reported Fredrick T. Addicot, a professor emeritus of botany at the University of California, Davis, who recently returned from a drive through Northern California and Oregon. Because the year has been so dry in that area, he added, colors are browner than usual.

In the Napa Valley, Forrest’s favorite foliage route leads north from the city of Napa on Highway 29. The route turns left on Redwood Road, right on Mount Veeder Road, right again on Dry Creek Road, and continues straight as the name of the road changes to Oakville Grade and a wide view opens of the valley below. Later, Oakville Grade drops down and returns to Highway 29, about 10 miles north of where the loop began. Nearby lie many of Napa’s well-known wineries. Many trees were just beginning to show fall colors last week; leaf season there usually runs into early November. For more information, contact the Napa Valley Conference and Visitors Bureau at 707-226-7459.

A sampling of other California possibilities:

* In Yosemite National Park, fall colors tend toward yellow--most notably black oaks, dogwoods, azaleas and big-leaf maples--and stand out against the green of the area’s myriad pines. The drought--in its seventh year and still going strong in Yosemite--might mute the foliage colors, but some rain did fall in mid-September, which could bode well for color. Northbound travelers entering the park via Highway 41 should keep in mind that elevations on that route reach as high as 6,000 feet, and leaves there often change color early in October. At lower altitudes, peak foliage viewing often arrives around mid-October. As of last Tuesday, many dogwoods had gone rust-red, and some maples and black oaks in cold spots had turned yellow.

The most-watched of all Yosemite’s trees, said ranger Betsy Clopine, is a 50-foot-high sugar maple planted by settlers about 120 years ago.

“It’s a non-native tree,” noted Clopine, “but it has historical value to us. It’s across from the chapel (on the main road into Yosemite Valley from the south, Southside Drive), in the area where the early village was.” For more information, contact the Park Service at (209) 372-0200.

A fall visit to Yosemite is also a chance to avoid the largest crowds. Park Service figures from 1991 show 608,000 park visitors in August, falling to 456,000 in September, 332,000 in October and 170,000 in November.

Another foliage spot that rangers recommend is an unnamed old road that leads past the base of Bridal Veil Fall Trail and concludes near the most popular spot for viewing El Capitan rock. To make that walk, park in the Bridal Veil Fall parking lot near the western entrance to the valley.

* In the Gold Country northwest of Sacramento, the fall colors brighten 19th-Century streets and Victorian homes in the old mining towns of Grass Valley and Nevada City. Maples, liquidambars, aspens and elms are the main attractions, some of them imported by the area’s Gold Rush settlers. Among the most colorful streets in Grass Valley: West Main Street, Colfax Avenue, Church Street, Mill Street, Chapel Street, East Empire Street. In Nevada City: Nevada Street, Boulder Street, Park Avenue Extension, Nile Street, Prospect Street, Searls Avenue, Zion Street, Sacramento Street, South and North Pine Streets, Spring Street, Broad Street and Main Street.

Dawn McDowell Bateman, executive manager of the Grass Valley/Nevada County Chamber of Commerce, estimated that the colors will begin to deepen right about now, reach their most vivid in the third week of October, and last through the first half of November. Upcoming events there include an Oktoberfest at the Nevada County Fairgrounds next Sunday, “Designs for Living” home tours countywide next Saturday and Sunday, and an Oct. 23-25 antique show and sale at Miners Foundry in Nevada City. More information is available through the chamber of commerce at (800) 655-4667.

* Along Highway 395 near Bishop, in the foothills of the Sierra Nevada about 200 miles south of Reno, leaf-seekers can find cottonwoods and liquidambars in the valleys and aspens at the higher elevations. Jan Sutton of the Bishop Chamber of Commerce reports that the high-country colors are flaring now and will probably peak in mid-October. Recommended high-country routes: Highway 168 west from Bishop to Bishop Creek Canyon; Highway 395 north to Rock Creek Recreation Area, Mammoth Lakes or June Lake. Valley routes, which are expected to offer the richest colors in late October, include Warm Springs Road and Collins Road southbound from Bishop. Last week, tips of valley trees were just beginning to turn.

* Between Yucaipa and Big Bear in San Bernardino County, Highway 38 winds for about 40 miles and offers a variety of fall scenery. Most of the trees were still green last week, and peak color was expected in mid-October. A short distance to the south of the highway, off the Bryant Street exit, Oak Glen Road stretches for about seven miles past farms and roadside businesses outfitted for fall. Several sites offer apple picking, along with arts and crafts displays, fresh cider and antiques. More information is available through the Yucaipa Chamber of Commerce at (714) 790-1841.

* Between Avila Beach and San Luis Obispo, drivers in See Canyon can find a dozen roadside stands offering fresh fruit, organic honey and the like, backed by apple orchards. The route is partially dirt road, but comes recommended for its views by the American Automobile Assn. and the local chamber of commerce.

From Highway 101 northbound, exit at Los Osos Valley Road and head toward Los Osos past Madonna Road. At Perfumo Canyon Road, turn left and follow the road uphill into See Canyon. Perfumo Canyon Road becomes See Canyon Road, and leads to views of the coast and some fall colors. From the terminus of See Canyon Road, westbound San Luis Bay Drive leads back to Highway 101. For more information, contact the San Luis Obispo Chamber of Commerce at (805) 781-2777.

* In the mountain town of Julian, 60 miles northeast of San Diego on Highway 78, apples and fall colors are the mainstay of the local economy. About 15 apple orchards operate in the area, many with roadside sales stands, and on autumn weekends the town’s streets and sidewalks are jammed with visitors who sample apple pie, browse the antique stores, watch melodramas in the old Town Hall, or stand in line for horse-drawn buggie tours of the countryside.

“From mid-September to the end of November, every weekend, we have something going on,” said Billie Rasmussen, secretary for the Julian Chamber of Commerce. Julian locals advise their friends to visit on Wednesdays, Thursdays and Fridays, when the crowds are smaller. (The crowds are small on Mondays and Tuesdays, too, but Dudley’s, the much-loved and much-patronized bakery seven miles west in Santa Ysabel, is closed on those days.) The most vivid foliage colors in the area are usually found around Lake Cuyamaca, nine miles south of Julian on Highway 79, in late October and early November. Scattered fall colors were beginning to appear last week. For more information, contact the Julian Chamber of Commerce at (619) 765-1857.

AAA officials also suggest foliage-watching along Highway 101 in Northern California, where patches of maple and cottonwood usually deepen into vivid colors around the first of October; U.S. 299 from Eureka to Redding, which tends to peak in mid-October, and Lassen National Forest, which usually peaks near the end of October.

Auto Club officials and park rangers note that travelers usually find prime viewing beginning in early October at altitudes above 6,500 feet. At lower elevations, the leaves often turn two weeks later. Auto Club officials also remind travelers to keep their attention on their driving until their car is parked safely.

“If you’re going to look at trees,” counseled AAA spokesman Jeff Spring, “find a place to pull off the road and really look.”

Also, start looking in the early morning. “More moisture on the trees makes the leaves sparkle a little more,” said Spring. “And for me, there’s more of a fall feeling, because it’s a little brisker in the morning.”

Outside of California, but still west of the Mississippi, lies a broad spectrum of further possibilities.

* In Northern Arizona, oaks and sycamores fill Oak Creek Canyon off U.S. 89A near Sedona. Frank Miller, executive director of the Sedona/Oak Creek Canyon Chamber of Commerce, said peak season for fall colors begins about mid-October and lasts about a month, unless heavy rains arrive and knock leaves to the ground early. For more information, contact the Sedona/Oak Creek Canyon Chamber of Commerce at (800) 288-7336 or (602) 282-7722.

Just north of there, 14 miles from downtown Flagstaff, drivers can take Snowbowl Road off U.S. 180 to a 9,000-foot altitude. The view takes in a substantial chunk of the Colorado Plateau, Flagstaff and a valley dotted with aspens--”white trunks and brilliant yellow leaves,” promised Linda Chandler, manager of visitor services for the Flagstaff Visitors Center (800-842-7293 or 602-774-9541). The panoramas from the north rim of the Grand Canyon also gain color in fall.

* In Telluride, Colo., the local chamber of commerce is advertising three-day, two-night fall foliage packages through Oct. 15. For $101-$170 per person (excluding air fare), visitors get two nights’ lodging in a local hotel and a half-day Jeep tour from Telluride Outside. More information is available from the chamber at (800) 525-3455.

* About 35 miles northwest of Bend, Ore., drivers can thread their way through the pines, firs and deciduous trees and bushes of Deschutes National Forest to the shores of Suttle Lake. Rich Mathis, managing partner of the 21-campsite Suttle Lake Resort and R.V. Park (503-595-6662), recommended that California drivers make their way into Oregon and north to Bend on U.S. 97. From there, U.S. 20 leads to the banks of mile-long Suttle Lake, where the deepest colors are expected in the first two weeks of October.

“It’s 80 degrees out here, the lake’s crystal clear and there’s not a soul around,” said Mathis one day last week. “It’s so serene. Oops-- there is one sailboat out there in the water with the sails down. I’m here by myself, except for the guy on the sailboat.”

In Salem, tour operator Shirley A. Barnard suggested that “a lot of people have gone to New England and found it too crowded. There needs to be a new destination. Ultimately, we (in the northwest) are going to be that destination.”

(Barnard’s OregonWest Excursions has been offering northwestern foliage tours for three years. This year, she organized a nine-day, mid-October bus itinerary beginning in Portland, ending in Seattle and carrying a price tag of $1,125 per person for all lodging and some meals. The passenger list is full; another tour is expected next year.)

* In Washington, in the Bavarian-flavored town of Leavenworth, 118 miles east of downtown Seattle, local leaders yesterday were scheduled to open their annual Washington State Autumn Leaf Festival, planned to continue through next Sunday. The Autumn Leaf Festival includes all-day oompah music in the city park on Front Street, art shows, hayrides, hiking and microbrewery tours. By the estimate of chamber of commerce manager Laura Jobin, deciduous trees in Leavenworth outnumber the human population (1,600) by a 200-1 ratio. The most colorful foliage in the area is usually seen the first half of October.

Jobin’s recommended driving route is a loop of about 240 miles: From Seattle, head east on Interstate 90, then north on U.S. 97. Turn west on U.S. 2 and continue to Leavenworth. From there, continue northwest on 2 until it intersects with Interstate 5, then head south on 5 back to Seattle.

In northern Utah, U.S. 89 runs through Wasatch National Forest canyons and the city of Logan (population: 33,000), offering maples, aspens and pines--that is, reds, yellows and greens--in close proximity. In most years, those colors peak between mid-September and mid-October, but a cold spell has hastened fall’s arrival this year.

For those planning ahead for next year, she suggested two driving routes: from Logan southwest on 89 to Brigham City, a 30-mile route that leads through colorful Wellsville Canyon, and from Logan northeast on 89 to Garden City, a 40-mile drive that leads through Logan Canyon. For more information, contact the Cache Chamber of Commerce (Logan is in Cache County) at (801) 752-2161.

* For those ready to travel farther, there’s Alaska. Last year, the AAA asked two of its “road reporters”--professional wanderers with 650,000 miles of automotive travel between them--to list some favorite foliage routes. They included the usual suspects, such as New Hampshire’s Kancamagus Highway and State Road 100 in Vermont, but one authority, Mike Mouser, found his favorite foliage along a 90-mile stretch of George Parks Highway in Denali National Park, between Fairbanks and Anchorage. John Beiler, a development specialist for Alaska’s division of tourism, said the route is rich in spruce, birch, aspen and poplar. Drivers climb from sea level to 2,000 feet; the vegetation and colors evolve along the way.

At the state’s higher altitudes, on the Dalton Highway between Fairbanks and the Yukon River, drivers above the tree line are treated to fall tundra and berry bushes--”fire-engine red and purples and other colors like that,” said Beiler, “in rolling tundra, in all those different shades.” (For more information, contact the Alaska Division of Tourism at 907-465-2010.)

In all leaf searches, however, travelers are advised to be flexible, and accept that no one can predict the perfect viewing day. Depending on temperatures, wind and rain, tree timetables vary from year to year.

And while they do react to cold, trees are immune to guilt. “Plants,” said professor Addicot in Davis, “are cold-blooded animals.”