My cousin gifted me this tree, neither him and I are certain what type of tree this is. Regardless, to get thickness in the trunk I should let this tree grow grow grow. It has some more time to keep growing in its current container, should I be clipping the tall leggy branches?
That doesn’t appear to be a Brazillian raintree (pithecellobium tortum). It certainly looks like it is a member of the Fabaceae family of plants which includes acacia and albizia. If there were thorns, I’d say acacia, but not seeing any thorns, I’d lean towards albizia. Many albizia in bonsai are albizia julibrissin (aka silk tree or mimosa), but I think the bark color is different. I’ve tried growing a variety of acacia and albizia. The closest thing this resembles is albizia forbesii. I don’t have any of these any longer because growing bonsai from seed produces a great deal of ugly trees, and all of mine were ugly. The a. forbesii were my favorite of all the trees. I just couldn’t get the root base to do what I wanted. It twisted and turned too sharply to make an interesting base. (or I didn’t have the skills to teach it to grow nicely)
You may need to keep it alive for a few years to see what the flowers and seeds do. That’s often the best way.
If the tree has thorns, post photos.
Just another note as I’m finishing, Dichrostachys is another branch of the Fabacae family you can investigate. Dichrostachys cinerea produces a beautiful multi-color flower. I had success with the seeds, but I couldn’t get the roots right on these, either.
My money is on that being a type of Acacia or Mesquite. My understanding is that raintrees have much smoother trunks, and very long thorns.