I gotta agree with Furby. Don't fall into that myth about retiring on your walnut trees. It would be like basing your retirement on the lotto ticket that aint been drawed yet.. Its the rare tree that has any higher value then any other marketable hardwood species of tree., If these trees are yard trees, odds are they are worth nothing to a buyer, only perhaps to you. Yard trees or open grown trees generally do not have the form to create what is valued in a high dollar walnut. Those big dollar trees are generally the slow growing, forest grown trees. Those trees that had to fight for sun and grew tall and straight and slow.