I created these cards using an oval mask I created from a piece of cardstock.
Using this technique will enable you to use a variety of stamps to create your scene.
I used a mask and sponge to create the background. I then removed the mask and added the trees and such to the interior of the masked area. The large tree on the side was stamped without the mask and outside of the masked area. Give a look at your stamps I'm sure you'll find you have some that will work with this technique.
I used Tim Holtz ink pads to stamp and various stamps..