Be sure to have replacements made as backups. The investment is very high, but the cost is justified by esthetics, significance of the interpretative theme and the thousands of visitors per week using the trail, which is usually paved or specially reinforced. Audio Tapes Portable audio-tape units are useful, but expensive, interpretation devices. However, with cheap, reliable cassette players, a relatively inexpensive aid may be made available. A tape that the user starts and stops as he moves from point to point is most practical.
Earphones help to limit interruptions for other hikers.
Problems may be expected in repairing damaged players, replacing worn-out tapes and replacing player units. These units are flexible means for interpreting a trail, since erasing and remaking the tapes is all that is required. The audio tape unit is very useful for special learning projects in school outdoor labs. Guided Tours Guided tours may be used as a supplement to self-guiding nature trails. They are useful for certain organized groups, when an able leader makes them effective.