According to Psychological Science, people who took a walk in nature performed 20 percent better on memory tests over those who took a walk in the city. These tests were administered immediately after each activity. It’s believed that a walk in the woods helps the brain recharge, which enhances short-term memory. Short-term memory helps you recall conversation details and phone numbers.
http://www.examiner.com/x-4352-Houston-Hiking-Examiner~y2009m6d22-Hiking-can-improve-shortterm-memory--Houston-hiking