The over-all objective of the study is the development of a methodology by which the terrain of tropical areas can be evaluated as to its military significance and the terrain components which are derived grouped into complexes and regions that have military meaning. The methodology can then be used to evaluate the Panama Canal Zone as a military tropical testing site. The report is concerned with the presentation of a classification of selected factors of tropical terrain, and with the application of the natural vegetation factor of the classification to the Canal Zone.