This is a missable achievement that can be obtained in chapter 2. The game does have chapter select if you miss it and need to go back.
At the beginning of the chapter, follow the instructions until you reach the point where you're asked to use the GPS to identify a tree marked with an X and take the SLR camera on the tripod over to that tree and print a photo of the tree.
Instead of following these direction, point the SLR camera at some other part of the landscape other than that particular tree. Return to the camper and hit the print button on the computer. Take the photo and fax it. You'll get a phone call telling you that you didn't photograph the correct tree. Grab the photo and fax it again. You'll get a phone call asking you if you know what a squirrel looks like. Repeat a third time. This phone call should include a comment about an amateur natural geographic photography contest (or something to that effect) and the achievement will unlock at the end of the conversation.