Are my Pecan trees dead?



Here’s an update with the pictures.
First is the full tree. A little over 3 feet tall.
Second is a scratch test from midway up the tree. Green underneath. You can see the thickness of the tree in these shots.
Third is a scratch test from around the base of the tree. Not green.

All the other trees I planted around this time aren’t like this. But maybe Pecan just has thicker wood at the base?