The residue pictured does not look like mold (at least, nothing infectious or tied to plant disease), though it's hard to tell what caused the sunken-looking portion of the trunk in that area. It might be a girdling root or an old canker. We can't ID the tree from the images since we can't see foliage or flowers/seeds clearly, but your description of the seed pods sounds like Sweetgum (botanical name Liquidambar styraciflua), which is a common native species. You can explore the linked page for a gallery of images for comparison.

If you have concerns about tree health or stability, have it evaluated by a certified arborist or licensed tree expert. While they cannot cure existing diseases or reverse any damage to the wood, they can help narrow-down a diagnosis and look for sources of tree stress that might be able to be addressed. (Like girdling roots, which can be costly to expose the more advanced they become.) Sometimes, obvious symptoms of a problem in trees don't develop until months or even years after the issue began, so early detection can be very beneficial.

Miri

Thank you!

You're welcome!