Personal tools
You are here: Home Wildland Resources Wildland Fire Management and Planning Unit 5: Fuel Moisture

Unit 5: Fuel Moisture

Document Actions
  • Content View
  • Bookmarks
  • CourseFeed

Natural Fuels   ::   Environmental Factors   ::   Timelag   ::   Dead Fuels   ::   Ignition & Combustion   ::   Exercises


Upon completion of this unit you will be expected to:

  • Explain fuel moisture timelag and its value to fire managers.
  • Name the six stages of vegetative development of living fuels (foliage), and give the average percent moisture content of each.
  • Explain the relationships between relative humidity, wind, and moisture content of fine fuels and of large fuels.
  • Explain how the amount and duration of precipitation affects moisture content of both fine fuels and large fuels.
  • Describe how fuel moisture is determined for fuels in each of the four timelag categories for a fire area.
  • Determine fuel moisture contents for dead 1-hour timelag fuels from fuel moisture tables, given necessary site data.
  • Explain moisture of extinction, how it varies in natural fuel complexes, and how it affects fire ignition and spread.


The purpose of this unit is to help you make estimations of moisture content in various dead and live fuels, to identify those fuels which can burn, and to assess the chances of ignition from firebrands landing in new fuels or of fire spreading by preheating fuels ahead of a flaming front. You will also recognize that fuel moisture content is a very important input toward making fire behavior calculations and predictions.

Copyright 2008, by the Contributing Authors. Cite/attribute Resource . admin. (2005, September 28). Unit 5: Fuel Moisture. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: This work is licensed under a Creative Commons License Creative Commons License