Picturing Yosemite: this unique course offers an artful way to show forestry students just how influential their decisions can be.

It's barely light as three dozen sleepy-eyed students with loaded backpacks greet one another on the campus of the University of california-Berkeley. We're here for a field trip, but the goal is much loftier than just admiring new scenery. These forestry students are attempting to understand how a century of forest management and popular portrayals have influenced what we now see. The ultimate goal is to have the folks who will shape our future forests realize how widespread and longlasting the effects of their decisions can he.

Right now, though, the students are focused on the present--and hoping a snowstorm won't derail their two-day field trip to Yosemite National Park. A few minutes later the word comes from forest ecology professor Joe McBride: It's still snowing in Yosemite but expected to clear. Without delay, Tania Martin, the graduate student instructor for the course, urges everyone toward waiting vans. We clamber aboard and head southeast.

The course, "The American Forest: Its Ecology, History, and Representation" was created by McBride and art history professor Margaretta Lovell. This trip, near the end of the semester, will test how well this novel course has met its goals.

The assignment: Look at paintings and photographs of Yosemite from the 1850s to the early 1900s, then compare them to the actual landscape. McBride and Lovell believe a first-hand look at the still-lingering results of forest management decisions made during the 19th century will give students a sense of the longevity and consequences of their actions.

In looking at the artwork, students would consider how and why artists represented American forests the ways they did in art and popular imagery: as dark, wild, and threatening; as mythic; as fairytale space; as Eden; and as a sublime setting.

"Students need to be aware of various images of forest and how these images may reflect and influence public opinion--and their own thinking," McBride says. To do that, McBride and Lovell drew from literature and art; architecture; the study of American politics, culture, and values; forest history and ecology; and public-forest management policies.

Freshman Joe Wright says the class "opens up ways of lacking at things. The subject matter is presented with different lenses: science, culture, and art. We see how they play off one another."

AN OBSTRUCTED VIEW

shhHWWUUUMP. Melting snow bombs slip off the tree limbs, punctuating our conversation. We're standing in a deserted picnic grove among the cinnamon-colored trunks of incense cedars. The snow has stopped, hut the clouds still hang low and dark.

Each team receives a plastic envelope containing reproductions of artwork that portrays Yosemite, a map of the valley floor, a clinometer to measure angles, a protractor, tape measure, and these instructions: Go by foot, shuttlebus, or van, and search for the precise location from which you think the artwork was made. Compare the artist's rendering of landscape to current conditions. Be ready to tell about your experiences, thoughts, and conclusions at the evening campfire.

McBride and Lovell began class with a description of the forests of America, from the cypress-tupelo-sweetgum forests of the southeastern coast to the Douglas-fir forests of the Pacific Northwest. Throughout the semester they knit together the forests' histories, their ecology, historical uses of wood and harvesting practices, artists' portrayals, and the evolution of national forest policy.

Students reviewed images of forests in art and popular culture to trace how American attitudes toward forests have unfolded. For example, in Thomas Cole's "The Hunter's Return" (1845), he portrayed the clearing of the forest as a first step in civilizing forest wilderness. During the same time period, farmers cleared vast tracts of forest in the Ohio River valley.

By contrast, in the second half of the 19th century Albert Bierstadt painted "The Great Trees, Mariposa Grove, California" (1876), embracing the wildness of the American forest. Concurrently, the federal government set aside land and forests in national parks and forest reserves. Students saw not only how artists' representations of the forest mirrored popular attitudes, but also how these images contributed to the development of national forest policies.

Back to the field trip: The dismal weather does not waver and McBride worries whether the cloud cover will obstruct the valley's features. A group of students peers toward the place where Half Dome should be, their arms extending as calipers. They measure canyon depth, tree height, and valley width, trying to characterize the species composition and tree density, both in the landscape before them, and in works by painter Thomas Hill and photographer Ansel Adams. The students begin to wonder: Has the geomorphology of the Merced River changed?

After dinner, students drift back toward the campfire circle. The sky is clearing, and Half Dome is visible through buttery clouds as students begin their presentations. The first group holds up their paintings: "Sentinel Rock" (undated), by Hill and "Yosemite Valley" (1868), by Bierstadt. The students' voices tumble over one another, although their stories and analyses are laced with frustration at the limited visibility.

"We found a spot, and the angles and ratios pretty much lined up, then the fog started to move and we found we were in the wrong place, looking east instead of west," was one typical comment. Tired, we finally head for our sleeping bags, making our way through a maze of tent cabins that glow like paper lanterns.

The next morning we soak up strong sun and coffee, marveling at the change sunrise has brought. The clear air seems to magnify each detail of the walls, waterfalls, and trees soaring above us.

We pile into the vans and revisit yesterday's sites. Near the Ahwahnee Hotel we find a meadow from which Bierstadt made field sketches for his 1864 work, "Valley of the Yosemite." Golden light flooding up the valley creates the sense of the sublime so often invoked by Bierstadt.

Since Bierstadt sketched there ponderosa pine have invaded the meadow, forming a wall that obscures the Merced River. This change was brought about by the 1864 Yosemite Grant, which halted the Native American practice of using fire as a land management tool. The Miwok people, who lived in the valley for at least 2,000 years before the arrival of Europeans, relied on acorns as a mainstay of their diet. To prevent competition from pines the Miwoks burned groves of oaks to clear out ponderosa pine seedlings.

From our vantage point nearly 140 years later, natural succession of ponderosa pine has reduced the original area of the meadows in Yosemite Valley by almost half. This process was helped along when a portion of the Merced River channel was lowered in the late 19th century to drain marshy areas and alleviate the flooding visible in Bierstadt's painting.

The landscape before us still bears the imprint of those past generations--their uses of the forest, management practices, belief systems, and ideas.

From the spot where Bierstadt composed "Valley of the Yosemite," the students can see how he manipulated the proportions of the valley and its enclosing walls to heighten viewers' awe. The original painting, measuring about 5 feet by 8 feet, stunned viewers when first exhibited in New York City in 1865 at the National Academy of Design.

As we pile into the vans to head home, we share a sense of wonder at what we've seen in Yosemite Valley. To echo the words of John Muir, from "My First Summer in the Sierras":

"The noble walls--sculptured into endless varieties of domes and gables, spires and battlements and plain mural precipices--all a-tremble with the thunder tones of the falling water. The level bottom seemed to be dressed like a garden-sunny meadows here and there, groves of pine and oak; the river of the Merced sweeping in majesty throughout the midst of them and flashing back sunbeams."

M. Kloss is an environmental writer in the Bay Area of California.