Portugal is a Mediterranean country with some
Atlantic influence near the coast, strongly conditioned by physical, biological, and
climatic environmental characteristics. The forest area is 3.3 million ha, and the mix of
species is represented, in decreasing order, by Pinus pinaster Ait., Eucalyptus
spp., Pinus pinea, Quercus suber, and with lesser representation by other
coniferous and broadleaf species.
Private property is 87% of the total forest area. The size of private
forest properties ranges from 2 ha in the northern part of the country to 100 ha in the
south. Most of the owners, however, do not show any interest in the management of their
stands, regardless of mature recently established stands. In addition to these facts the
climatic conditions of the country – the precipitation in continental Portugal is
ranging between 5 to 65% of potential evapotranspiration - and the low population density
create conditions for forest fires very expressive both in number and in burnt area.
The North of Portugal is affected by a higher number of forest fires,
although its contribution to the total annual burned area is small.
On the contrary it is the centre of the country, with a mean size of
forest property of about 30 ha, a very high rate of forest cover and reforestation (mostly
by Eucalyptus spp., and Pinus pinaster), and low population density, that
most contributes to the total area burned per year, with a few large fires.
In the South of the country the Mediterranean characteristics are very
strong and the majority of the forest systems are the typical "montados"
with dominant species like Quercus suber and Quercus rotundifolia in pasture
lands regimes. For that reason the number of forest fires is not yet significant.
Tab.1. Forest fire statistics for Portugal 1990-1999. Note: The data of 1998 and 1999 are preliminary.
Year |
Number of Fires |
Burned Area (ha) |
Forest
Surface Burned |
Brush
and Grass Area Burned |
Total
Area Burned |
1990 |
10 745 |
79 549 |
57 703 |
137 252 |
1991 |
14 327 |
125 488 |
56 998 |
182 486 |
1992 |
14 954 |
39 701 |
17 310 |
57 011 |
1993 |
16 101 |
23 839 |
26 124 |
49 963 |
1994 |
19 983 |
13 487 |
63 836 |
77 323 |
1995 |
34 116 |
87 554 |
82 058 |
169 612 |
1996 |
28 626 |
30 542 |
58 325 |
88 867 |
1997 |
23 497 |
11 466 |
19 068 |
30 535 |
1998 |
34 676 |
57 393 |
100 975 |
158 389 |
1999 |
31 714 |
25 124 |
25 994 |
51 994 |
In the next ten years the scenario
may significantly change because in addition to the extreme edaphic and climatic
conditions a large-scale programme of afforestation on agriculture lands has been
initiated under the support of the European Community rules that aim to increase forest
cover.
Forest Fires
The Portuguese Forest Services has the
responsibility of the management of the data base on the forest fires and mapping of
burned areas. Whit an average of 20 000 forest fires per year it is necessary to
expeditiously develop a methodology for mapping and validation.
Since 1990 the Portuguese Forest Services in collaboration with the
Forestry Department, Technical University of Lisbon (Universidade Técnica de Lisboa -
UTL) is using satellite remote sensing (Landsat) imageries for mapping burned areas
larger than 5 ha. This work has began as a research project and today it is considered an
operational product for mapping burned areas (Fig.2).
Fig.2. Landsat composite colour image (RGB-743) with the
perimeter of the surface burned in 1998 in Vieira do Minho region.
Fire Prevention
During the fire season major forest fires occur
between June and October. At the National Co-ordination Operational Centre (CCON) the
Forest Service supports a multidisciplinary team for decision making in large forest fire
situations.
Since 1998 a map has been developed for strategic purposes that shows
landscape features that are related to the resistance of fire propagation (scale
1:250,000). The map is available in analogue and digital formats (CD-ROM). Landscape
susceptibility to fire spread is expressed in three levels:
- Null
- Agriculture riparian vegetation, land burned in the last two years, urban and
irrigated agricultural areas
- Medium
- Brush land and rock outcrop
- High
- Forest land and brush with high density and fuel loads
The Portuguese Forest Service whit other state
departments and universities is actively engaged in research projects. A recent example
the project GEOFOGO "Simulation of Propagation of Forest Fires" (home page:
http://geofogo.cnig.pt) that
provides a simulation of the forest fire propagation based on the fuel and fire spread
model by Rothermel, and also provides weather data and a geographic information system.
This program can be use in forest management to reduce fire risk, and to support decision
making in fire fighting in large-fire situations. The system can be used also as tool of
information of students and to sensitize the public on forest fire behaviour.
The Portuguese Forest Service is cooperating with the National Geographic
Information Centre (CNIG) in the project APERTURE. This project which is supported
by the European Community started in December 1997 and aims to produce remote sensing
images that allow identification of land-use change after forest fires.
The Ministry of Agriculture is responsible for forest fire prevention and
detection and coordinates 238 fire detection towers which cover the whole country and are
operated continuously during the forest fire season. During 2000 a 2001 the Forest Service
is testing a pilot project that explores utilisation of automatic fire detection systems,
as a support to traditional systems.
Prevention Strategies
The adoption of national forest management plans,
with the support of advanced scientific and technical knowledge, will reduce the negative
impacts of forest fires on the ecological and socio-economic systems.
Since 1999 regional forest management plans (PROF and PGF) are in place
for privately owned forests.
Also in the regional since 1993 the PMIF (Local Administration Service
Plan for Forest Intervention) are effective which are regional plans of forest
intervention whit the target to adopt some actions of forest protection, e.g.
identification of areas of high fire risk, prevention needs, detection and fire fighting
means. This plan contains the forest fire risk maps for the Local Administration Service.
It also proposes forest management options including special measures for areas at high
wildfire risk.
This elaboration of these plans, at Local Administration Service, allows a
geo-referenced information system with support the actions of the management in each
region for defence against the forest fires.
In the country regions where the level of forest fires is very high, these
plans are very important for the Regional Forest Management Plans (Plano Regional de
Ordenamento Florestal - PROF).
The participation of forest owners and there associations in forest
protection is in its initial phase (since 1999) with the establishment of teams of "Sapadores
Florestais" (fire guards), who work all around the year in the detection, survey,
management of stands, and in support of fire suppression activities.
Conclusions
The problem of forest fires in the Mediterranean
region is related to environmental and socio-economic factors. The defence of forest
ecosystems against destructive fires must be based on inter-sectoral, cooperative and
multidisciplinary approaches. Some examples have been given above. Public information on
the importance of the forest and the associated space is very important. Forest fires is
not a national problem but a European and global issue. Proper forest fire management is
determinant in the sustainable development of forests all over the World.
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