Except for the difficulties of installing a rope in the tree with the woods on one side of the tree and a ditch and road on the other, the kitty's rescue was pretty simple and easy. Though she was frightened by the disturbance I created in the tree when installing my rope, she calmed down by the time I climbed up to her, and she never moved from her original position. She was resting next to the trunk of the tree in the crotch of a large limb about 25 feet high.
Amy checked with her neighbors and created a post on the Lost Pets web page, but as of this writing, the owner has not been found. If the owner is not eventually found, Amy will find a good home for the kitty. While I refer to the cat as a "she," the fact is that I never was able to determine the gender definitively, so a correction may be needed in the future.