Plot and Project relationships

1. A vegetation plot is collected as part of a project.

2. A plot can contain subplots defined by a recursive relationship

3. A plot contains information that will not change between temporally separated observations of a plot. Transient information is stored in the Observation table. There must be at least one observation for every plot, and multiple observations are possible.

4. Some plot attributes are constrained to fall within fixed lists. These include USGS quadrangle, geographic area (e.g., country, state, county), soil type, named place of occurrence, and other identified in the list of picklists.