The oddest tree I know of is poplar, which is incredibly common around here and is basically considered junk wood. Turns out, those individual, fast-growing trees are in fact stems of a large underground root system.

One of these trees has 47,000 stems:

> Most agree [...] that Pando encompasses 42.89 hectares (106 acres), weighs an estimated 6,000 metric tons (6,600 short tons) or 13.2 million pounds, and features an estimated 47,000 stems, which die individually and are replaced by genetically identical stems that are sent up from the tree's vast root system, a process known as "suckering". The root system is estimated to be several thousand years old, with habitat modeling suggesting a maximum age of 14,000 years and 16,000 years by the latest (2024) estimate.[

https://en.wikipedia.org/wiki/Pando_(tree)

My favorite odd tree is the ginkgo. The way the leaves are look ancient, like a tree from a fargone era. And it is exactly that.

Also the fruit was fun to throw at people when I was a kid... Very stinky.

Poplars have underground roots, but they are not "underground root stems" per se. Their main stem is the trunk we see growing above ground.

I'm mostly using the terminology from the Pando article. The article quotes a "Mitton and Grant" as writing:

> quaking aspen regularly reproduces via a process called suckering. An individual stem can send out lateral roots that, under the right conditions, send up other erect stems; from all above-ground appearances the new stems look just like individual trees. The process is repeated until a whole stand, of what appear to be individual trees, forms. This collection of multiple stems, called ramets, all form one, single, genetic individual, usually termed a clone.

Poplar is considered junk wood? This is news to me. I’ve seen plenty of poplar furniture.

It’s too soft to be of much use except the odd piece of furniture (for which it is pretty terrible because it dents too easily). As a woodworker finishing it also sucks because the fibers tear too easily. Its grain pattern looks bland at best, it ages poorly, and its color is too inconsistent from tree to tree.

That said, it’s one of the most stable woods so it doesn’t warp much which is why it’s a popular base material for plywood and it’s easy on cutting tools. I usually only use it for the interior parts of drawers.

Which is all great for arrow shafts actually. Just may need to be thicker than usual.

The Mary Rose shafts seem to mostly have been poplar.

Not that this would be very relevant nowadays but still.

It also grows very fast, particularly (per acre) if closely spaced, which makes it of interest for biofuels.

https://farm-energy.extension.org/poplar-populus-spp-trees-f...

It's considered to be a poor firewood around here, as well.

It's often used as trim that's painted over, as many don't consider the wood pretty. I love seeing poplar with a wide variety of colors.

It’s brittle, light and flimsy. It has its uses but is not great for furnitures or burning.

Ceiba speciosa maybe? That is a weird tree for sure. I grew up where there were wild thorny honeylocust trees. The trunks are spotted with dense clusters of branching thorns, some of which are 8" long and stiff enough to puncture tractor tires. To paraphrase family guy, nature is scary.

Sounds like the nightmare tree I had to deal with as well. I never did find out what it was. Does the honeylocust produce a bunch of red berries? My dad used to get mad at me as a teen when I’d be lazy and not pick up the fallen limbs from this tree and puncture the tractor tires. It was to the sole reason I became very proficient at using the tire repair kit.

Yeah, we've got these in Beersheba (south of Israel). The only tree my ten year old won't climb. They've also got really interesting cotton-like fruits, though I'm not brave enough to taste them.

I don't know if you are talking about Drunken tree (palo borracho in spanish) but once playing soccer in a field with some of them I ended with around 15 funny parallels cuts. Good old times.