JeffGu
Antagonist/Heckler
The two most common woods used to make pallets are Southern Yellow Pine and Oak... but it varies a lot by region and purpose. A pallet company here in Nebraska (now defunct) used Cottonwood because it's tough and springy and is very easily obtained in this neck of the woods. I once got one that was made from birch. No idea why... maybe it was made for some specific purpose.