From the BLM website:
The Describing Indicators of Rangeland Health (DIRH) technical reference contains a simple, repeatable protocol to describe and quantify 17 indicators of rangeland health. The protocol uses a combination of quantitative measurements and qualitative observations. This protocol does not rate degree of indicator departure from an ecological reference; instead, a standardized system is used to classify and describe each of the 17 indicators independent of a reference. DIRH may be used in many ways, including (1) rapid assessment when it is not feasible to conduct an Interpreting Indicators of Rangeland Health (IIRH) assessment (2) supplementing standardized quantitative monitoring data with structured observations of difficult-to-measure indicators, (3) facilitating education and communication about rangeland conditions and ecology, (4) informing the development and revision of rangeland health reference sheets and ecological site-specific evaluation matrices, (5) expanding the scientific understanding of the relationships between changes in quantitative indicators and ecosystem processes, and (6) informing subsequent completion of IIRH assessments using an appropriate reference sheet.