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1. Definition
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Name
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FIRE
FREQUENCY
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Brief
definition
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The
frequency or return time with which forests are burned
by wildfire
|
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Unit
of measure
|
Number
of fires per year on the surface unit of a defined
territory, registered over a long period
|
|
Spatial
scale
|
|
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Temporal scale
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2.
Position within the logical framework DPSIR
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Type
of Indicator
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Driving
Force/State
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3.
Target and political pertinence
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Objective
|
The
indicator contributes to roughly define the fire regime,
i.e. the average number of times fire burned a territory
affected by desertification during a long period.
|
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Importance
with respect to desertification
|
Fires
ignited through natural causes have interacted over
evolutionary time with ecosystems, exerting a significant
influence on ecosystem functions: fire recycles nutrients,
reduces biomass, influences insect and disease populations,
and is the principal change agent affecting vegetative
structure, composition, and biological diversity.
As humans alter fire frequency and/or intensity, increasing
the size and severity of fires, many plant and animal
communities are experiencing a loss of species diversity,
and site degradation. Today human activities are causing
major disturbances to natural fire regimes around
the world: by increasing the rate of fires and by
setting fires in forests that would seldom burn under
natural conditions; by suppressing natural fires,
causing ecological damage and leading to infrequent,
catastrophic fires due to a build-up of inflammable
material. Some analysts think that destructive fires
cause as much forest loss and degradation as poor
logging practices and agricultural conversion. Forest
removal, by burning, strongly simplifies forest landscapes,
e.g. by truncating age distributions and reducing
diversity, therefore inducing more vulnerability to
wildfire.
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|
International
Conventions and agreements
|
The
UNCCD recognised the particular conditions of the
Mediterranean affect desertification processes, including
the extensive forest coverage losses due to frequent
wildfires (Convention text as of September 1994 and
as of September 2001).
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Secondary
objectives of the indicator
|
This
indicator represents the impact of fire on land and
the average damage on forest and rural ecosystems.
Information about fire frequency can help in addressing
political measures to recognise areas with the highest
fire hazard, and to organise an efficient fire fighting
system to reduce the fire problem and indirectly combat
desertification.
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4.
Methodological description and basic definitions
|
Definitions
and basic concepts
|
The
frequency or return period with which forests are
burned by wildfire, evaluated through the annual data
of wildfire events over a long period for a defined
area.
|
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Benchmarks
Indication of the values/ranges of value
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class
I - score 1: A forest ecosystem burned every 100 and
50 years on average will be considered unchanged or
barely altered;
class
II - score 1.33: A forest ecosystem burned every 25
years on average will be considered to be moderately
altered;
class
III - score 1.66: A forest ecosystem burned every
15 years on average will be considered highly altered;
class
IV - score 2: A forest ecosystem burned every <15
years on average will be considered extremely altered
and very prone to desertification processes which
start with changes in cover, structure and biodiversity.
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|
Methods
of measurement
|
Number
of forest fires registered on a defined area, possibly
over a very long period (about 100 or 50 years).
|
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Limits
of the indicator
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This
indicator requires information on both the historic
and current fire frequency. While current fire frequency
data are not difficult to collect for large areas,
it is not easy to determine the historic fire frequency
on a restricted forest covered area. The limits of
the indicator include the difficulty in finding statistical
fire data and homogeneous data on burned surfaces
for different European countries, at a municipality
level. Researchers have estimated historic fire frequencies,
but data have been measured at a Mediterranean level
(through tree ring scars and similar evidence) at
only a few sites and forest communities (Vega Hidalgo,
2000)
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Linkages
with other indicators
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Burned
area, Fire risk
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5.
Evaluation of data needs and availability
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Data
required to calculate the indicator
|
Number
of fire registered per year over a long period over
a given area
|
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Data
sources
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National
Forest Fire Statistics
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Availability
of data from national and international sources
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Data
on historic fire regimes can by provided by the EUROSTAT
and National Statistics Services. Satellite data too
can be used to measure current fire frequencies through
systematic registration of ignition points, but available
data cover only very recent years.
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6.
Institutions that have participated in developing the indicator
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Main
institutions responsible
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University
of Basilicata, Italy
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Other
contributing organizations
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7.
Additional information
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Bibliography
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Vega
Hidalgo J.A. Resistencia vegetativa ante el fuego
a traves de la historia de los incendios. In: Velez
R. (ed.) 2000 La defensa contra incendios forestales:
fundamentos y experiencias.McGraw Hill, Madrid
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Other
references
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Nardiello
D., 1998 - Attivitą di prevenzione contro gli incendi
boschivi e cartografia di rischio: applicazione alla
Val d'Agri dell'analisi territoriale multidisciplinare
(Sistema A.F.S). Thesis Accademic Year 1997-98
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Contacts
Name and address
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Prof.
Agostino Ferrara
University of Basilicata
Polo Universitario di Macchia Romana
85100 Potenza, Italy
e-mail: ferrara@unibas.it
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