A German forest ranger recently made news with persuasive claims that trees have social networks similar to those of humans, and wrinkle as they age just like us.

He’ll get no argument from sex-positive crusader Annie Sprinkle and her partner, Beth Stephens, who enthuse about their current passion — ecosexuality — to anyone who will lend an ear. The pair will be leading tours of Walker Art Center this weekend as part of a 12-hour “Winter of Love” party, definitely a new twist on Valentine’s Day celebrations.

Then again, taken in tandem with the “Hippie Modernism” exhibit now lining gallery walls with Whole-Earth-Catalog this and psychedelic-communal-be-in that, it’s actually more retro. Sprinkle, a former stripper and prostitute turned sex educator and artist, and Stephens, a professor at the University of California, Santa Cruz, talked over one another on the phone in their excitement. They explained the concept of ecosexuality as something both obvious and enigmatic.

“It’s all about enjoying the sensuality of nature while getting people to think about their relationship to the Earth and taking better care of it,” said Sprinkle, née Ellen Steinberg, who at age 61 retains a charmingly girlish, throaty manner of speaking.

“It’s quite Duchampian,” she said, referring to artist Marcel Duchamp’s fluid tenets about what constitutes art. “If we want to have sex with a cloud, we take it as a lover.”

Wait — what?

“It doesn’t have to be genitally based, it’s about connections we can’t see,” Stephens said. “When I breathe air out, Annie breathes it in. Everyone has a biome cloud filled with bacteria surrounding their bodies, so when you’re in a room with a lot of people, who knows what those clouds are doing?”

Let’s not think about Zika right now.

During the party (2 p.m. Sat.-2 a.m. Sun.), Sprinkle and Stephens will give a “Make Love With the Earth” presentation at 7 p.m., then lead ecosex-celebrating tours (9:30 and 11:30 p.m.) of the Walker with some local talent in tow to chime in, including performance artists Patrick Scully, Heidi Arneson and Xandra Coe.

Other activities include group meditations at 5 and 7 p.m., a literally cosmic planetarium projection copresented with the Bell Museum (8 p.m.-1 a.m.), some psychedelic-spin action with hip-hop party king Tiiiiiiiiiip (11 p.m.) and several 1960s-’70s films, including a rarely seen Rolling Stones documentary (9 p.m.) by famed American photographer Robert Frank, who went behind the scenes on the Stones’ 1972 tour.

As for the whole ecosexual thing, even skeptics can look on the bright side for at least one reason, Sprinkle said.

“It means that on Valentine’s Day, everyone can have a lover — the sky, a tree, a river.”