Each of the 18 units in this collection addresses a different environmental problem. An introduction precedes the collection of activities and appendices provide lists of forest animals and plants and lists of food webs. A glossary is provided as is a bibliography. Each unit includes: (1) a list of objectives; (2) a summary; (3) a discussion of advance preparations including lists of materials; (4) teaching suggestions; (5) procedures; (6) alternative methods; and (7) suggestions for further activities involving various subject areas where appropriate. (RE)