What is LANDIS-II?

LANDIS-II is a forest landscape simulation model. Forest landscape simulation models estimate forest change over large spatial scale (typically > 10 ha) and longer time scale (> 10 years). Forest landscape models simulate succession (changing species composition) and disturbances.

Many landscape forest simulators simulate succession using successional states and transitions. In such models, the forest states are defined a priori and there are a fixed number of states (ranging from 3 - 50). Transitions between successional states are determined by a probability, age, disturbance, or some combination.

In contrast, LANDIS-II is an individual species model. The model user defines a number of species and key life history characteristics (or attributes). These attributes determine where and when a species establishes, how long it grows, how it responds to disturbances, etc. Therefore, these attributes determine the successional strategy for each species.

LANDIS-II does not (currently) represent individual trees. Because LANDIS-II was intended for simulating large landscapes, trees are lumped into species cohorts (bins). LANDIS-II uses age to define cohorts because many attributes are age-dependent. At each site on the landscape, a species-age cohort is present or absent. A cohort may also have ancillary information, such as biomass in one or more compartments (e.g., wood and leaf). Many other forest simulators use species and diameter cohorts and LANDIS-II is theoretically capable of accommodating other types of cohorts (they must still be divided by species).

LANDIS-II emphasizes spatially dynamic processes (often called contagious or landscape processes). These are processes that are dependent upon the neighboring or surrounding landscape. For example, species colonization of a site is dependent upon the presence of mature cohorts nearby. Fire is a contagious process that spreads from neighbor to neighbor, dependent upon the quality of fuels. Harvest stands are defined by managers and include a set of neighboring sites or cells.

See Mladenoff 2004 (PDF) to learn more about LANDIS model history.