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Variation in Fire Frequency and Areal
Extent from 1985-1995 among Ecological Land Units of the Northern Lake States
Mark A. White and George E. Host,
Natural Resources Research Institute
University of Minnesota
Duluth, MN 55811
Fire frequency and behavior have been shown to be strongly
influenced by both climate and substrate characteristics.
Climate affects fuel moisture levels and regional vegetation composition,
while substrate influences local vegetation and fuel moisture level.
Since climate, substrate and vegetation composition are embedded within
Ecological Classification Systems (ECS), these classification schemes should be
a good predictors of fire frequency and behavior. This study extends the
analyses within Great Lakes
Assessment Fire Project by summarizing fire occurrence data at
different hierarchical levels of the Ecological Classification System as applied
in Minnesota, Wisconsin and Michigan.
The fire database is comprised of point locations
indicating the year of occurrence and fire size in acres.
We examined fire frequency and areal extent within three different levels
of the Ecological Classification System hierarchy: section, subsection, and land
type association (LTA). The section
and subsection level analyses include all three states, while the LTA level
includes only northern Minnesota and Wisconsin, as this level of classification
is not yet available across the rest of the study region.
We used the data in its 10-year aggregate form.
The following measures were calculated for each ECS level.
1) Ignitions per square mile, 1985-1995
2) Percent area burned 1985-1995
3) Maximum fire size 1985-1995
4) Mean fire size 1985-1995
5) Coefficient of variation of
mean fire size 1985-1995
6) Fire cycle 1985-1995 (number of
years to burn area equivalent to land unit)
7) Mean area burned per year
Fire Distribution and
Intensity Maps
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Number of Ignitions |
Mean Area Burned |
Maximum Area Burned |
Percent Area Burned |
| Section |
 |
 |
 |
 |
| Subsection |
 |
 |
 |
 |
| Landtype Association |
 |
 |
 |
 |
The analyses indicate that the ECS stratification and hierarchy do account for
variability in fire regime characteristics at the different spatial scales of
section, subsection and LTA.
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