LANDFIRE Succession Classes (SCLASS) 3.1.0, Great Basin LCC (Idaho Section)

Broad-scale alterations of historical fire regimes and vegetation dynamics have occurred in many landscapes in the U.S. through the combined influence of land management practices, fire exclusion, ungulate herbivory, insect and disease outbreaks, climate change, and invasion of non-native plant species. LANDFIRE produces maps of historical fire regimes and vegetation conditions using the disturbance dynamics model VDDT. These maps support fire and landscape management planning outlined in the goals of the National Fire Plan, Federal Wildland Fire Management Policy, and the Healthy Forests Restoration Act.

Succession Classes categorize current vegetation composition and structure into up to five successional states defined for each LANDFIRE Biophysical Settings (BpS) Model. An additional category defines uncharacteristic vegetation components that are not found within the compositional or structural variability of successional states defined for each BpS model, such as exotic species. These succession classes are similar in concept to those defined in the Interagency Fire Regime Condition Class Guidebook (www.frcc.gov). This layer is created by linking the BpS layer with the Succession Classes rulesets. This geospatial product should display a reasonable approximation of Succession Classes, documented in the LANDFIRE Vegetation Dynamics Models . The current successional classes and their historical reference conditions are compared to assess departure of vegetation characteristics; this departure can be quantified using methods such as Fire Regime Condition Class (FRCC).

Five successional classes, "A" (1) - "E" (5) define successional states represented within a given BpS model. 'UN' (6) represents uncharacteristic native vegetation for the BpS model on which these vegetation conditions are found. These are taken to represent vegetation cover, height, or composition that would not have been expected to occur on the BpS during the reference condition period. 'UE' (7) represents uncharacteristic exotic vegetation for the BpS model on which these vegetation conditions are found. Additional data layer values were included to represent Water (111), Snow / Ice (112), Barren (131), and Sparsely Vegetated (132). Non-burnable Urban (120), Burnable Urban (121), Non-burnable Agriculture (180), and Burnable Agriculture (181) are provided to mask out such areas from analysis of vegetation departure.

To use this layer for assessing vegetation departure from historical reference conditions, it is necessary to combine this layer with LANDFIRE BpS and LANDFIRE map zone data layers. The subsequent combination of map zone, Bps, and Succession Class can then be found within LANDFIRE Historical Reference Condition tables. Caution is warranted in assessing vegetation departure across map zone boundaries, as the classification schemes used to produce BpS and Succession Classes may vary slightly between adjacent map zones. Furthermore, reference conditions are simulated independently for each map zone, resulting in potentially unique measurements of reference conditions for a given BpS between adjacent map zones.