LANDIS Landscape Disturbance and Succession model

LANDIS is a forest landscape model designed to simulate forest growth, competition, seed dispersal, succession, and disturbances (including fire, wind, harvesting, insects, and ungulate browsing), across large (100,000 - 10,000,000 ha) landscapes. LANDIS represents landscapes as a grid of cells and tracks age cohorts of each species (biomass or density) rather than individual trees. LANDIS simulates distinct ecological processes, allowing complex interactions to play out as emergent properties of the simulation.

LANDIS was developed beginning in the late 1990s with partial funding from the Northern Research Station. Development was a joint effort among Dr. David Mladenoff (University of Wisconsin), Dr. Hong He (University of Missouri), Dr. Robert Scheller (Portland State University), Dr. Eric Gustafson (NRS), and Dr. Brian Sturtevant (NRS). The current version (LANDIS-II) was designed using modern software engineering techniques and allows users to select from an extensive library of process-based modules (extensions) to customize the model for specific applications.

LANDIS-II is a modeling environment in which users “plug in” extensions that independently simulate specific processes or output specific cell or landscape attributes, each operating at a user-defined time step that is consistent with the process being modeled. All extensions interact with the vegetation “currency” used to represent the tree cohorts existing in the landscape cells. Current cohort currency options include age and biomass, or age and stem density.  

Cohort establishment, growth, competition and senescence mortality are modeled within LANDIS-II using a succession extension. Currently available succession extensions include:

• Age-only succession – simulates succession using just the cohort age currency. 
• Biomass Succession - simulates succession as competition for growing space using the cohort biomass currency. 
• Forest Carbon Succession - derived from the CBM-CFS3 Forest Carbon model. 
• PnET Succession – derived from the PnET ecophysiology model to simulate photosynthesis as a competition for light and water with direct links to temperature and CO2 concentration, using the cohort biomass currency.  Can also track soil temperature (including ice) and site albedo (boreal only). 
• Net Ecosystem CN Succession – simulates succession as competition for growing space, and tracks above and below ground carbon, nitrogen and water, using the cohort biomass currency.
•  Density Succession – simulates succession as competition for growing space, and tracks cohort age, mean stem diameter and stem density. 

Disturbances remove some or all of the vegetation in cohorts found on the cells affected by the disturbance in each time step. Each disturbance process is modeled either mechanistically or statistically (or a combination). General types of disturbance extensions include:

• Fire
• Wind
• Biological Disturbance Agents (e.g., insects, disease)
• Harvest
• Drought
• Browse (e.g., deer, moose)

LANDIS II is Open Source. Software and source code are available without charge.