WHAT IS THE LANDIS MODEL

LANDIS is a spatially explicit landscape model designed to simulate forest landscape change over large spatial and temporal scales (Mladenoff et al. 1996, Mladenoff and He 1999). LANDIS 4.0 simulates the dynamics of forest succession, seed dispersal, wind, fire, biological disturbance (insects and diseases), harvesting, fuel accumulation and decomposition, and fuel management. Differing from most landscape models, LANDIS simulates multiple landscape processes in combination with the simulation of succession dynamics at the tree species level.

LANDIS MODEL DESIGN CONSIDERATION

LANDIS is designed with these considerations:

• It simulates forest landscape change over large spatial ( 10³ - 10⁷ ha) and temporal ( 10¹-10³ years) scale with flexible resolutions (10-500 m pixel size), balancing ecological complexity with current and foreseeable computational capability.
• It simulates the main natural and anthropogenic disturbances and their interactions with adequate mechanistic realism for these broad scales.
• It simulates species-level forest succession in combination with disturbances and management.
• It assumes that detailed, individual tree information and within-stand processes can be simplified, allowing large-scale questions about spatial pattern, species distribution, and disturbances to be adequately addressed.
• It uses a component-based, object-oriented design that provides users with the flexibility of parameterizing and simulating only the processes of interest.
• It uses classified satellite imagery as input, and output is compatible with most GIS software.
• It requires moderate parameter input since for most landscapes in these scale ranges available input data may be coarse and parameters may be poorly estimated.

LANDIS does not predict specific disturbance or management events. Rather, it is a scenario model that compares long-term effects of various disturbance and management scenarios on the simulated landscape.

THE NEW FEATURES IN LANDIS 4.0

• LANDIS 4.0 is a component-based program using multiple dynamically linked libraries (DLLs), each having a standard interface and simulating a distinct process.
• A biological disturbance agent (BDA) module was added to LANDIS 4.0 to simulate the effects of one or more insect and/or disease disturbances.
• A fuel module was added to track fine fuel, coarse fuel, and live fuel and to evaluate the effects of common fuel treatments on the simulated fire risk (see 9.5.7.6 in the User Guide for definition).
• LANDIS 4.0 has a newly designed fire module that incorporates terrain, wind, and fuel information into the simulation of fire.
• In LANDIS 4.0, landscape heterogeneity is no longer assumed to be stratified only by land type map (or ecoregion). Landscape heterogeneity can now be processed using individual disturbance regime maps as well as the land type map.
• LANDIS 4.0 is now a Windows program, with companion graphical interfaces for input (LI.exe) and viewing output (LV.exe), which are independent of GIS software.
• LANDIS 4.0 automatically detects and accepts 16-bit input for all input maps. Consequently, the number of map classes that can be processed has increased from 256 to 65,536.
• LANDIS 4.0 preserves all the functionality of previous versions of LANDIS (e.g., LANDIS 3.7).

LANDIS IS SUITED TO ANSWER THE FOLLOWING QUESTIONS

• How do disturbance and successional dynamics interact to change forest patterns on large, heterogeneous landscapes and what are the expected recovery paths of the tree species after disturbance in the simulated landscape?
• Will fire suppression lead to large, catastrophic fires? If a large catastrophic fire were to occur, what are the long-term effects on forested ecosystems?
• Where are areas of high fire probability and high potential fire intensity on forest landscapes, how do these areas change over time under different fuel reduction plans?
• What are the effects of common fuel treatments such as prescribed burning and coarse woody debris reduction? What should be the treatment frequency, size, and intensity in order to maintain a forested landscape where fire is less likely to occur?
• What are the effects of forest harvesting and do the harvest activities performed at the stand scale alter species composition and spatial pattern at the landscape scale?
• How does seed dispersal influence landscape change and how significant is the initial seed source abundance and distribution for ecological restoration?
• How does insect disturbance influence the spatio-temporal pattern of forest composition and age? Does insect damage significantly influence long-term fire risk?

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