FireWorks for the Sagebrush Ecosystem - M06: Ladder Fuels & Fire Spread: The Tinker Tree/Shrub Derby
Course Type: FireWorks activities
Availability: Public access
Author(s): FireWorks Educational Program
Date Created: 2018

Cataloging Information

  • crown fire
  • fire spread
  • fuel arrangement
  • ladder fuels
  • surface fire
Partner Site(s):
Record Maintained By:
Record Last Modified: November 17, 2018
FRAMES Record Number: 25849


Overview: In this activity, students use a physical model to learn how the vertical arrangement of fuels (ladder fuels) affects the potential for fires to spread into tree and shrub crowns. Teams create “tinker tree” models and compete by lighting simulated surface fires under the “trees.” Those with unburned “foliage” advance to a final round with more surface fuel. Students use a handout to guide their inquiry and analysis.

Note: This activity applies to sagebrush ecosystems, as well as forests. For example, invasive plants like cheat grass can act like ladder fuels, since they are fine, dry, and burn intensely; this allows surface fires to spread to the tops of large shrubs. Also, juniper and pinyon pine have been encroaching into sagebrush ecosystem areas. And forests containing a number of tree species can be found at higher elevations and in riparian areas adjacent to sagebrush ecosystem areas.

Lesson Goals:

  • Increase students’ understanding of the relationship between fuel arrangement and vertical fire spread
  • Develop student skills in making predictions, engineering, experimentation, and written communication


  • Students will design a model tree /shrub and assess its ability to “survive” a surface fire.
  • Students will analyze the role of different types of surface vegetation and litter in forest and sagebrush ecosystem fires.