Lesson Overview: Students learn about mixed-severity fire and the complexity of actual historical fire regimes. They study information from a published research project, model results, and maps showing present patterns of fire severity. Then they use their understanding to create a stand age diagram for a hypothetical forest in the Sierra Nevada with a mixed-severity fire regime and decide if their imagined forest has a fire regime that is substantially different from its historical fire regime.

Lesson Goals: Students understand the nature of mixed-severity fire regimes and their contribution to landscape-level diversity in the Sierra Nevada. Students can use a quantitative method to describe a hypothetical concept. Students can make a judgment call based on quantitative information.

Objectives:

• Students can draw a hypothetical stand age diagram that depicts a history of mixed-severity fire and shows how it influenced the distribution of two or more tree species in the forest.
• Students can judge whether their hypothetical forest shows a pattern of fire now that is substantially different from its historical fire regime.
• Students can state some potential ecological consequences of a changed fire regime.