This ecological classification system was developed for southwestern Alberta through the analysis of vegetation, soil, site, and forest productivity information. The hierarchical classification system has three levels-ecosite, ecosite phase, and plant community type. Thirty-seven ecosites are described with further detail provided by subdivision into ecosite phase and plant community type. A soil type classification system that describes seventeen soil types was also developed and is presented here. Management interpretations are made for drought, excess moisture, soil rutting hazard, soil compaction hazard, puddling hazard, soil erosion hazard, frost heave hazard, soil temperature limitations, vegetation competition, and windthrow hazard. Color photos and drawings are presented for 112 common plants of southwestern Alberta, and an index listing common and scientific names of illustrated plants is included. Keys to ecological variables, definitions of soil horizon designations, and a glossary are also included.