1000-hour timelag

adj. Of or pertaining to a dead fuel particle with a timelag of 1000 hours.


  • Discussion


Fuel particle timelag is based on the amount of time necessary to lose or gain 63 percent of the difference between the initial moisture content and the equilibrium moisture content at a constant temperature and relative humidity. A 1000-hour timelag fuel particle has a low surface-area-to-volume ratio and therefore adjusts slowly to changes in equilibrium moisture content.  




Dead fuel particles between three and eight inches in diameter are considered to have a 1000-hour timelag (about six weeks). Fuel particles in this size class are not considered in fire behavior models because they generally donít contribute to surface fire spread. However, the heat produced by burning fuel particles three inches and larger can strongly influence fire effects, such as tree mortality and soil heating. In addition, this larger-diameter fuel, when rotten and dry, can be readily ignited by firebrands.