Albert Oehlen, Untitled (Baum 84), 2016, oil on Dibond. STEFAN ROHNER/©ALBERT OEHLEN/COURTESY GAGOSIAN

Albert Oehlen, Untitled (Baum 84), 2016, oil on Dibond.

STEFAN ROHNER/©ALBERT OEHLEN/COURTESY GAGOSIAN

Albert Oehlen started painting trees decades ago, if he ever actually started painting trees.

“In the beginning, when I first had the tree in the painting, it was, um—I needed some motif as an excuse to paint something at all, any bullshit is good enough,” Oehlen told me earlier this year. “I thought, the tree, ah! Such a kitsch motif of bad photography—I thought, ah, this is fine.”

We were walking into his show at Gagosian Gallery’s West 21st Street space in New York, “Elevator Paintings: Trees,” which closes tomorrow after a two-month run. It consists of two suites of paintings. There are the “Elevator Paintings,” abstractions that feature Oehlen’s process of staging and restaging new juxtapositions between various shades. And then there are the Tree Paintings (Baumbilder), a continuation of a series the German artist started more than three decades ago that has never shown in New York.

While he picked the tree because, as he said, “any bullshit is good enough,” it quickly became more than just that.

“Then I started thinking, what makes it a tree?” Oehlen said, smiling. He was in town for a just a few days—he lives in a remote chalet in Switzerland—and was wearing sneakers, a blazer, a T-shirt, and stubble, looking like an aging punk rocker. Which he is, sort of—he’s technically a member of Red Krayola, Mayo Thompson’s freak-psych outfit, though he said he never actually played in it. (He also designed the album art for Arthur Russell’s 1986 single “Let’s Go Swimming.”)

“I can go here, I can go there, and whatever I do, it is still a tree as long as there’s something in the middle rather thicker to the outside,” he went on, continuing to fill out the story of his trees as he glanced at a particularly striking one, Untitled (Baum 84), (2016), with the reds in blocks atop the “tree,” which was black and sloped like a roller coaster. “And wow, this is a formula, a very simple formula, super easy, like 12-tone music.”

“But if Schoenberg had told it to the wrong person,” Oehlen said, referring to the Austrian composer who wrote revolutionary dodecaphonic music, “they would have said, Come on, this is not serious—the formula is super easy, and then comes the labor.”

Oehlen is often called the finest painter of his generation, and of that generation of German artists who emerged from the post-Beuys ether—Richter, Kippenberger, Polke, Kiefer—perhaps it’s Oehlen who’s the most influential. One of his most celebrated groups of works are his “Computer Paintings,” which were featured prominently in his last big New York show, “Albert Oehlen: Home and Garden,” at the New Museum in the summer of 2015. These works are rooted in the mechanical, the calculated: he decided on the designs using a program that he had installed on his first laptop. The fact that he later would go over them with brushstrokes by hand should add a touch of the human, but ironically, he touched them up to make them more computer-like. Computer programs in the 1990s just weren’t precise enough to make things that looked like they were made on a computer.

The work in the show at Gagosian, by contrast, glow with the organic, and not just because they depict trees. The Elevator Paintings, for instance, are almost like landscapes of feeling, made in Segovia, Spain, where he has a studio that sounds like it’s basically just a shack.

“I did this in Spain, in the fresh air,” he said, walking up to one of the “Elevator Paintings.” “In Spain I have a very raw, a very simple studio, no heating, no comfort at all, the air blows through the thing—it’s fantastic. But it’s not the idea of like—oh, the light in Tuscany is different. What I call them are atmospherics, how I feel.”

Oehlen said the subject of the work is basically just the tension between colors, a playful approach to palette that allows Oehlen to riff on the futility of chasing good taste.

“First, I created some challenging bonds, color combinations that are kind of forbidden to me: this red and yellow confrontation, the green and red,” he said. “So this is really tough, because there’s a big danger that it looks like the paintings on the walls of the construction work, or kindergarten kids’ paintings, or misunderstood wild paintings. All this is very close.”

In the two years since the New Museum show, Oehlen’s market has been hit with a shot of adrenaline. In October 2016, at the postwar and contemporary evening sale at Christie’s in London, Untitled (Statue of Liberty), 1989, sold for £1.3 million (about $1.7 million), a new record for the artist. Just months after that, also at Christie’s in London, that record was smashed when Selbstporträt mit Palette (Self-portrait with Palette), 2005, sold for £2.9 million ($3.6 million).

It remains to be seen how these newer works would do at auction—though a source did tell me that all the “Elevator Paintings” were bought up quickly by the French billionaire Francois Pinault, owner of Christie’s, so that could be a sign. And when I asked Oehlen about how these new works play into his long history of punk-like playfulness, he said it has to do with the line he crosses when a work goes from bad to good.

“I just enjoy making a big mess,” he went on. “I get to one point and then I say—it’s like turning a switch—then I say, Now it’s getting serious. No matter what it is at this moment, in three weeks I want it to be beautiful. I want it to be mine.”