Technical Abstract: Developing ecological sites requires knowledge of plant community dynamics and species interactions, as well as interactions between plants and soil properties, climate, and landscape features. Developers must know what questions to ask at the beginning of the development process, the data to collect in the field, and how to use the data to create and test ecological site concepts. Ecological sites are meant to provide a general ecological foundation for management. Ecological sites bring together several ecological concepts, including plant-soil interactions, succession and climax, non-equilibrium in community structure, and ecological gradients and spatial heterogeneity. Ecological sites integrate a variety of information sources, including inventory data that link plant communities to soil profiles and landscape position, historical reconstructions, and management considerations based on local knowledge and monitoring data. A well-organized plan is essential to properly develop a set of ecological sites. The steps in such a plan discussed here include (1) asking a set of general questions regarding ecological sites, (2) literature research and field visits for reconnaissance, (3) specification of initial ecological site concepts, (4) inventory data collection, (5) analysis and interpretation of data collected, and finally (6) refinement of ecological site concepts and the compilation of associated information into ecological site descriptions.