What causes this?

[Ed*L]

I took these yesterday in my woods.
I've always wondered what caused the tree to grow like this. It's like it grew over an old stump.
Overall the tree appears to be healthy, with no dead branches.
I'll also admit, it's one of the few trees on the property that I haven't been able to identify.

Ed

 

[smokechase II]

guessing

You often see certain species with pronounced butt swell.
Cyprus in swampy settings or old growth trees that are large and need more support.

If this did grow over a stump, that is not necessarily unusual. Hemlock in the NW will start on stumps and logs of all species, then as the stump rots away, the new hemlock - an entirely separate tree - will have grown enough that its roots that reach down to soil become part of the tree stem. The stump disappears and super neat small kid forts are available.

This looks funny to us, but what it represents is a neat adaptation that favors those species that can pull it off.

This may be what happened to your tree and it is in the later stages of those roots/stems growing together. Hopefully someone with familiarity with your neck of the woods will write in.

 

[turnkey4099]

The second picture looks like they are growing in swampy, possibly flooded part of the year, territory. Even the young trees in the background show the but swell so I doubt it is growing over a stump. Must be a very water loving species.

Harry K

 

[Bermie]

Bottle Butt?

Looks like there is a cavity in the base - this could be 'bottle butt' where the tree puts on reaction wood , in this case at the base, to compensate for the internal decay/cavity so it can still stand up!
BUT...not knowing what species and the waterlogging...?