If there’s a story behind each pair of shoes flung over the beleaguered branches of a tree overlooking the Mississippi River’s West Bank, then there are hundreds of stories, because there are hundreds of shoes.

Most of them, presumably, once shod students at the University of Minnesota, for the burdened tree is best seen while walking on the Washington Avenue bridge between the campus’ East and West banks.

You can glimpse it, fleetingly, from the Green Line light rail if you glance south at the right moment and see its strangely festooned branches. But by the time you think, “Were those shoes?” you’re long past and moving on to more pressing questions such as, “Oh, what’s for dinner?”

It’s the Shoe Tree, and that’s the only thing about it to be said with much certainty.

From a distance, it appears home to a dense flock of starlings. But up close, you see the faded orange spike-heeled pumps, the ice skates, the hiking boots and the moccasin slippers. Birds of a different feather. Scarlet-striped sneakers stand out like cardinals, while flashes of yellow suggest goldfinches. A green and purple pair could be mistaken for an errant parrot.

Mostly, though, the branches hold the sparrows of footwear, shoes in shades of gray and brown and black.

Look down, and the distant ground is littered with failed flings. Of the pairs that dangle from the furthest branches, well, you have to marvel at the audacity of launching such a mighty, fingers-crossed toss.

Or, maybe it was just, “Whatever.”

No one knows when people began flinging shoes into the boughs, although they’ve been doing it for decades.

No one knows why they do it, although the speculation can be entertaining.

It’s not even clear what kind of tree it is, but that’s beside the point, because it’s moved beyond forestry to become a sort of open-air reliquary where Pumas and Nikes and Timberlines and Tevas hang as sacred objects, slowly revolving like wind chimes, but soundless.

Because, rubber soles.

Art without complaint

Ralph Sievert, director of forestry for the Minneapolis Parks and Recreation Department, almost called the tree “iconic” before settling on “weird landmark.” He comes into the conversation because, despite being a university feature, the tree is rooted in a steep bank of parkway land.

Sievert has no idea when the shoe tradition began and said, frankly, he rarely gives the tree much thought, although he speaks of it kindly.

“It’s not something anyone has ever complained about,” he said. “So maybe that’s something.”

An attempt to bring some order to the disordered tree came about in 2013, when two gardeners from the U’s landscape department pruned shoes from nearby trees. But they were told to leave the original tree untouched, according to a story in the Minnesota Daily.

Yet more shoes again have appeared in trees to the west as flingers seek less populated branches, the footwear version of suburban sprawl.

Call them urban art, arboreal therapy or eyesores, but shoe trees are a thing.

Sneakers over power lines? That’s a whole other deal, with explanations less intriguing, even stupid. Not that stupid doesn’t figure in here, for many of the shoes in the U’s tree look to be in remarkably good condition.

There are dozens of shoe trees across the United States, according to a map on RoadsideAmerica.com that seems updated with some regularity.

“A shoe tree,” the site states, “starts with one dreamer, tossing his or her footwear-of-old high into the sky, to catch on an out-of-reach branch. It usually ends there, unseen and neglected by others. But on rare occasions, that first pair of shoes triggers a shoe-tossing cascade.”

So why?

There have to be stories, right? Compelling reasons, dramatic developments, glorious moments inspiring people to commemorate an event for posterity with a dangling pair of sneakers?

Short of catching someone in the act, the reasons remain mystifying.

From old articles in the Minnesota Daily, the odd blog and guesses by passers-by, several theories emerge.

Flingers may:

• be celebrating something such as passing a test.

• believe that a successful toss means they won’t fail the semester.

• have achieved a long sought loss of virginity.

• learn they’re going to graduate, after all.

• be copycats.

The big money’s on that last theory.

“Honestly, I don’t ever hear good stories about it,” said Erik Moore, in the U’s archives department, where little about the shoe tree has been archived. “I think most people just wonder what prompted someone to throw another pair of shoes up there.”

Yet he came as close as anyone to tracking down when this ritual began. A 2012 alumni magazine called it a “time-honored tradition of 45 years’ standing.” Because the Washington Avenue bridge was moved and rebuilt in 1965 to align with West Bank development, he said, that time frame makes sense.

Les Potts, director of land care at the U who retired May 1 after 41 years, has seen the phenomenon unfold, although with few, if any, memorable moments. Still, he gave a fond nod to the ritual.

“In a way it’s kind of — I wouldn’t say neat — but it’s happening on its own,” Potts said. Yet he added that the practice could kill the tree if the shoelaces girdle the trunk, wrapping it so that nutrients can no longer freely flow.

“We’ll have to check as it leafs out, see if the tips are dying back.”

Then again, it’s been years.

In any case, the coming leaves will camouflage the shoes to some extent, making the sight a little less jarring.

But sheesh, there are a lot of shoes.