Open-Source Fire Science
Open-Source Fire Science
The Land Use and Carbon Scenario Simulator (LUCAS) is a powerful modeling system that tracks how California’s land, vegetation, and carbon storage change over time in response to climate, wildfire, and human activity. Developed to inform statewide resilience planning, LUCAS integrates land-use transitions, vegetation growth, disturbance, and carbon accounting into a single, spatially explicit framework, making it one of the most comprehensive tools available for understanding the long-term evolution of California’s ecosystems.
At its core, LUCAS simulates annual changes in land cover, vegetation, and ecosystem carbon at a 1-kilometer resolution. It combines a state-and-transition model, which captures how land shifts among categories such as forest, shrubland, agriculture, and urban areas, with a stock-and-flow carbon model that tracks the movement of carbon among living biomass, dead organic matter, and soil pools. This design allows LUCAS to capture both the ecological dynamics of vegetation growth and decay and the human-driven processes of land-use conversion, management, and disturbance.
For vegetation and biomass modeling, LUCAS draws on a suite of geospatial datasets including LANDFIRE vegetation types, U.S. Forest Service Forest Inventory and Analysis (FIA) data, and the National Land Cover Database (NLCD) to represent structure, composition, and age across 28 forest types statewide. Forest productivity, decomposition, and disturbance responses are parameterized using data from the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) and the Integrated Biosphere Simulator (IBIS), ensuring that vegetation growth and carbon cycling respond realistically to regional climate and ecological conditions. Live and dead biomass pools are tracked separately, allowing the model to simulate post-disturbance regrowth and carbon recovery over time.
LUCAS also models carbon fluxes, including growth, respiration, and emissions, under changing climate and disturbance regimes. It integrates historical and downscaled CMIP6 climate data to adjust net primary productivity and decomposition rates annually, capturing the influence of temperature and precipitation on vegetation carbon balance. Wildfire, drought, forest harvest, and vegetation management events are incorporated as disturbance “flows,” dynamically removing or transferring carbon among pools.
In the Pyregence Project, LUCAS was coupled with the Fire Risk Simulation Model (FRSM) to simulate bidirectional feedbacks between vegetation change and wildfire behavior. FRSM uses LUCAS outputs, such as biomass and fuel loads, to estimate fire probability, area burned, and severity, while LUCAS incorporates those fire impacts to update vegetation structure and carbon storage for subsequent years. This fully coupled system captures the dynamic feedback loop between fire, fuels, and vegetation recovery, providing a realistic projection of how wildfire and management strategies shape long-term carbon dynamics.
Model outputs include annual statewide maps of vegetation composition, aboveground biomass, carbon stocks, and fluxes, as well as transition probabilities for land-use and disturbance events. These datasets are publicly available through the U.S. Geological Survey’s ScienceBase and the Cal-Adapt Analytics Engine, supporting planners, researchers, and decision-makers in developing strategies for forest resilience, wildfire mitigation, and carbon management under future climate conditions.