Learning activities in environmental education require the use of the physical environment or moving into nature and natural settings to explore issues of the environment. These approaches are sometimes labeled as "nonformal." This informational bulletin examines a taxonomy of four learning environments and explore the application of nonformal learning theory into practice in the arena of environmental education. The bulletin is presented in four sections. The first section establishes definitions for four learning environments: formal learning, nonformal learning, informal learning, and self-directed learning. The second section examines the roles of formal, nonformal, informal and self-directed learning related to environmental education. The third section discusses methods of improving nonformal education in environmental education by stressing the principle that learning is an individual process of meaning-making. The summary reemphasizes that learning outcomes can improve if nonformal learning is an opportunity for the learner to be active, volitional, internally mediated, and in the process of constructing meaning. (MDH)