Nature sounds are treasure boxes of information. They give us some clues as to the sound sources in terms of the identity, life cycle and interactions with other elements in the environment. They also tell us the type and nature of different events that take place close to or afar in the environment. The range and significance of nature sounds is the general foundation for the study of sound environments. Different habitats respectively hold the unique sound environment in terms of their acoustical characteristics and sound source species composition (SSSC). The acoustical indices such as taxonomic groups, locality bonds and trophic levels have made it possible to carry out environmental surveys without imposing a harmful effect on the local ecosystem as the conventional methods of collection and capture tend to do. SSSC monitored in a local area will be the main source for diagnosing and assessing the environment. In order to make use of such treasure boxes of nature sounds, however, we first need to learn properly how to listen to and hear nature sounds using our own ears. As part of the sound and environmental education, I would like to propose .a sound map method. The sound map is a handy way for both children and adults to describe and discover the sound environment. It is also an effective way to develop their hearing sensitivity and aural recognition of nature sounds in an enjoyable manner. Further, the sound map provides us with the means to share the image of sound environment with other people and is a good foundation for communicating and making decisions on it. To show the potentials of sound map method in monitoring and diagnosing environments, a pilot study made at a planned site of EXPO 2005 in Kaisho-no-mori Forest, Aichi, Japan is briefly introduced.