You can build a stand on almost any tree that has a "v" in it or two trees that are fairly close side by side. Just nail in some 2x4's across both of the trees until you get to your desired height. You then nail in two 2x4's on either side of the trees, parallel from each other. You then make a "top" to those two parallel 2x4's, forming the bottom of your treestand. All you need then is a little fold out chair to sit down on, or you can make a make shift chair from some of the scrapwood. I used to build alot them with my buddy.
This is kind of like it:
