The Landscape Fire and Resource Management Planning Tools Prototype Project, or LANDFIRE Prototype Project, required a system for classifying vegetation composition, biophysical settings, and vegetation structure to facilitate the mapping of vegetation and wildland fuel characteristics and the simulation of vegetation dynamics using landscape modeling. We developed three separate, fully integrated vegetation and biophysical settings map unit classifications that quantified, categorized, and described vegetation and environmental conditions; these include: cover type (CT), potential vegetation type (PVT) and structural stage (SS). We used a rule-based approach to implement these map unit classifications in the LANDFIRE reference database (LFRDB), which is a field-based database comprised of existing field data from the prototype mapping zones (Caratti, Ch. 4). We used the LFRDB to create training databases to develop maps of CT, PVT, and SS (Frescino and Rollins, Ch. 7; Zhu and others, Ch. 8). These vegetation-based maps formed the foundation for the mapping of fire regime condition class (FRCC), fire behavior fuel models, fuel loading models, fuel characteristic classes, and canopy fuel characteristics (Pratt and others, Ch. 10; Holsinger and others, Ch. 11; Keane and others, Ch. 12). The map unit classifications also formed the building blocks for the development of succession pathway models for simulating historical fire regimes (Long and others, Ch. 9).
In this chapter, we refer to our process of categorizing the biophysical settings, vegetation composition, and vegetation structure as a “classification” process. Several design criteria were developed to ensure that the LANDFIRE map unit classifications were sufficient for successfully completing the LANDFIRE vegetation, wildland fuel, and fire regime products. We refer to the complete list of units in each classification as a “map legend.” We call the results of each classification a “map unit” or refer to them by the appropriate mapping classification topic such as “cover type” or “potential vegetation type” or “structural stage.”