The Impact of Land Use Planning on Wildfire Risk: A Study in Southern California
Over the past three decades, most new homes in California have been built in or near the wildland-urban interface (WUI). As catastrophic fires in the WUI grow worse with climate change, effective fire-risk reduction strategies are essential.
In Land Use Planning and Wildfire: Development Policies Influence Future Probability of Housing Loss, Alexandra D. Syphard, Avi Bar Massada, Van Butsic, and Jon E. Keeley modeled three different development scenarios in San Diego to investigate how land use planning can influence the future probability of housing loss due to wildfires.
Key Takeaways
- Infill development produced the most efficient use of land, with the highest housing density; and the homes built were at the lowest fire risk.
- Leapfrog development – the construction of housing in isolated, undeveloped areas – consumed the most land to build homes at the lowest density; the resulting homes were at the highest risk of fire.
- To mitigate the risk of housing loss from wildfire, policymakers should concentrate growth on infill parcels where the risk is lowest.
The study simulated three scenarios of future residential development: infill, expansion, and leapfrog. Each scenario was based on an econometric subdivision model that estimated the likelihood of parcel subdivision. The simulations used MaxEnt, a machine-learning algorithm that predicts the probability of a structure burning based on various factors, including housing density, cluster size, and biophysical variables, to project the landscape-level wildfire risk to residential structures from 2010 to 2030.
These simulations revealed substantial differences in development patterns and wildfire risk among the three scenarios:
- Leapfrog Development in isolated, undeveloped areas resulted in the largest housing footprint, lowest housing density, and highest fire risk. This scenario produced fragmented development with many small, isolated clusters, making it the riskiest in terms of wildfire exposure.
- Expansion Development at the urban periphery had a moderate housing footprint and density, with fire risk initially high but decreasing over time. This scenario showed a mix of infill and leapfrog characteristics as development progressed.
- Infill Development where housing growth is concentrated within existing urban areas, produced the most compact development and the lowest fire risk.
Policies that promote higher-density, clustered development within existing urban areas can substantially reduce the future risk of housing loss due to wildfires. This approach aligns with broader ecological and conservation goals, highlighting the importance of strategic planning in mitigating wildfire impacts.