A few months after the Japanese attack on Pearl Harbor, Berkeley, Calif.-based artist Chiura Obata was sent to the Tanforan detention center. Tanforan, a racetrack about 10 miles south of San Francisco, was used as an assembly point for Japanese Americans forced into prison camps by President Franklin D. Roosevelt’s infamous wartime Executive Order 9066.

Obata’s work, a marvel of invention, nuance and emotional resilience, is the subject of a Smithsonian American Art Museum exhibition, now closed to the public because of the coronavirus outbreak. For now, it’s worth looking up his work online or purchasing the catalogue for the exhibition, and reveling in the poetic economy of Obata’s painting, and his deft distillation of this country’s natural and urban wonders into masterful watercolors and pen and ink drawings.

Obata was a successful art professor and an accomplished artist before the roundup of Japanese Americans. He had lived in the United States for almost 40 years, since he was 18 years old, and over the course of his career, he estimated he had taught some 10,000 students. When he arrived at the Tanforan stables where he was initially interred, he thought like a pedagogue, concerned first for the children he saw around him.

“This is a kind of sin that is intolerable,” he remembered. “From this sin, we have to bring these schoolchildren back to equality.”

The indignities of life in detention were particularly painful to Obata’s artistic sensibility. He came to the United States already trained in Japanese representational techniques, and he fused these skills with new ones, and new subject matter that he found in the American West, especially the mountains of California. Beauty was palpable to him, something he felt he needed to teach and pass on to his students. The natural world was a source of intellectual and spiritual nourishment that he tried to capture in his art. He went hiking in the High Sierra, explored the rock formations and meadows of Yosemite and walked the California coastline, finding inlets and bays that became distinctively Japanese in form as his brush reproduced them in watercolor and ink on silk and paper.

And suddenly he was in a drab, dehumanizing place, first a stable in California, then the barracks of Topaz, Utah, where he spent most of his time in internment. It was bleak, hot, arid and dusty, and he missed green things, trees and gardens. He moved quickly to establish an art school, both at Tanforan and later Topaz. And when he represented the camp at Topaz, the sense of displacement became dreamlike, even surreal, a luminous landscape that looked just a bit scorched, with a few dark buildings in the midground standing in for the enormity of what was happening there.

Obata was physically attacked at Topaz by an unknown assailant. He attributed the act to the toxic environment of the place, which addled ordinary minds and bent otherwise decent people to suspicion, animosity and violence. He was released in 1943, and moved to St. Louis for a time, where he made a bleak cityscape that captures hulking gray buildings, perhaps warehouses, on a snowy day, an open, depressing urban landscape in which even the small red bus in the foreground seems eager to pass through and off the page. Another image, made in the St. Louis suburb of Webster Groves, is as peaceful and enchanting as the cityscape is a study in urban misery: Two people sit in Adirondack chairs, in a cozy green garden. The angle of view, from a precipitously high point in the trees, gives this study of domesticity a distinctly Japanese sensibility.

After the war, Obata returned to teaching at Berkeley, where he died in 1975 at the age of 89. The exhibition suggests that the wartime internment camp experience may have deepened or intensified his art. Or perhaps that was a natural function of age and wisdom. He was horrified by Hiroshima, seeing it not just as a tragedy of war but an assault on nature, and he made a series of three watercolors, “Devastation,” “Prayer” and “Harmony,” that are among his most visually adventurous images. He was clearly aware of the new art currents of the mid-century in New York, and an untitled streetscape from the 1950s looks like he was channeling John Marin.

But a 1965 image, called simply “Glorious Struggle,” is the best place to end. It is a sumi-e image, an ink wash drawing on silk, in which a few, deft, calligraphic strokes capture a giant sequoia battered by wind and precipitation, perhaps rain, or snow. In a lecture, he seemed to speak as if through the tree itself: “Hear me, you poor man. I’ve stood here more than three thousand and seven hundred years in rain, snow, storm, and even mountain fire, still keeping my thankful attitude strongly with nature,” he said. “Do not cry, do not spend your time and energy worrying. You have children following. Keep up your unity; come with me.”

This magnificent painting, and those inspiring words, are off view for now. But the message is still vital, and any tree can teach it.

“Chiura Obata: American Modern” is scheduled to close on May 25. It is not currently on view because of coronavirus concerns. For more information, including an image gallery and videos, visit americanart.si.edu.