Among the many case studies presented in the book, the cleanup and trail development of Sand Creek in Denver stands out as having obvious benefit. The river flows through industrial areas and suffered impacts. Trail builders are repairing streambanks and educating people about the existing problems. Such impacts must be weighed with the benefits of the trail. The book covers key ecological concepts such as the zone of influence, edge effects, habitat fragmentation, landscape patterns, habitat quality, and species diversity.
Plants are also relevant, especially when they are threatened or sensitive.
Some concepts presented are controversial. For example the book does not mention the strategy of removing existing trails to reduce human impacts. We plan to update this handbook regularly and ask you to send information and suggestions. The study is available as a PDF file on the web site of the Colorado Department of Natural Resources.