Document


Title

Fire: short term impacts and long term implications for boreal Alaska
Document Type: Conference Proceedings
Author(s): M. Joan Foote
Publication Year: 2000

Cataloging Information

Keyword(s):
  • boreal forest
  • ignition
Region(s):
Record Maintained By:
Record Last Modified: December 3, 2015
FRAMES Record Number: 2157

Description

An understanding of the interaction of fuel, fire, burn severity, site, and site vegetation, is essential to predicting the primary and secondary short term and long term impacts of fire. After analyzing fire behavior and by following the changes in species composition and canopy cover for tree, shrub, herb, moss, and lichen taxa in permanently marked vegetation plots on the resulting burns for many (30) years on many vegetation types in the boreal forest of interior Alaska, I have realized the importance of fuel, its loading, distribution, type, and form, in determining where a fire can and can not go and how the fire will impact the ability of the site to regenerate. Fire is a collection of mini flames and is self perpetuating. Fire consumes the fuel it touches. Once consumed, the fuel is gone and the fire will self-extinguish unless it ignites new, usually adjacent, fuel. Organic matter of any type can be fuel. Characteristics of the fuel determine how easily the fuel will ignite and how long it will hold the flame. The inter-fuel distance determines the minimal flame length needed to reach the next patch of fuel. Weather variables like wind, relative humidity, rain, dew, and temperature, that change the moisture content or temperature of the fuel will alter its flammability. Fire also heats the area around the fuel being consumed. The longer the residence time of the flame, the greater the consumption, the more the heating and the larger the size of the area being heated. With consumption, live fuels are killed, the thickness of the organic layer is reduced, and patches of mineral soil are exposed. Heating can also kill live fuels. Heat, if sufficient, will melt the silica particles in sandy soils thus sealing the surface. Revegetation of an area following fire is dependent on 1) its recovery potential or the amount and type of live fuels, especially on-site seed or spores, and shoot-producing stems, roots or rhizomes, that survive the fire, 2) the amount of mineral soil exposed, 3) the potential for off-site in-seeding, and 4) the success of seedling establishment. Of these only the last is not directly influenced by fire and the severity of the burn. Fire as a process is the same wherever fire occurs. However the legacy of each site, even within the same vegetation type is unique. One must consider both when assessing the impact fire will have on a given area. Application of this knowledge will assist the land manager to determine if and when fire is the appropriate tool and the type of fire needed to do the job or the consequences if and when a wildfire is to be left uncontrolled.

Citation:
Foote, M. Joan. 2000. Fire: short term impacts and long term implications for boreal Alaska. Fire2000 conference, special session on frostfire; San Diego, CA.