Hi Adria,

This looks like poplar borer damage. See these pages:

https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/poplar/branchesholes.html

https://extension.usu.edu/planthealth/ipm/ornamental-pest-guide/arthopods/wood-borers/poplar-borer

While you can treat this, note that this native bug attacks stressed trees. How does the rest of the tree look? Is it fully leafed out, with leaves to the ends of the branches? If the tree as a whole is failing, it may be time to say goodbye. If you think the tree looks healthy, it would be worth consulting with a certified arborist to get a definitive diagnosis and talk about possible treatment.

You can find a certified arborist here:

https://www.treesaregood.org/findanarborist

I hope this helps. Good luck.