The project objectives are as follows: Phase I Model Development 1. Prepare a prototype FETM Version 4.0, incorporating any required revisions to the wildfire size and fire distribution algorithms. The prototype model would be used in the field test of candidate vegetation dynamics models being proposed by the Riverside Fire Laboratory. 2. Develop full FETM Version 4.0, incorporating all the modifications listed in the "Materials and Methods" section of this proposal. Phase II Sensitivity Testing 3. Test the sensitivity of model outputs to key model inputs, algorithms, and relationships. 4. Document and provide literature support for the component algorithms used in FETM Version 4.0. 5. Publish a technical paper supporting the core framework of FETM Version 4.0 in a national or international peer-reviewed scientific journal. Phase Ill Retrospective Application 6. Perform a retrospective application of FETM Version 4.0 in Yosemite National Park, year 1945-1950 to the present. Phase IV Technology Transfer 7. Prepare a comprehensive users guide and provide national and regional instruction on the theory and application of FETM to personnel within federal and state agencies.