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Rationale
In
July of 1979, a forest fire in the Ayora area (Valencia
province, Spain) affected an extension of approximately
30,000 ha, causing important repercussions at socio-economic
and environmental level. The burned wood alone was evaluated
to more than 6 million Euros. Since then, the local Forest
Administration has carried out various actions (firebreak
areas, reforestations, etc.) with the aim of palliating
the effects of possible forest fires in the future.
The
GEORANGE project will analyse the effectiveness of
these measures and, in collaboration with the forest managers,
propose new management plans to reduce the fire risk and
increase the quality of the existing forests.
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Location
The
Ayora site is located in the Valencia Community. With a
surface of approximately 3,200 km2, it includes
more than 60 municipal areas, although the project will
be centred especially in the 7 municipalities directly affected
by the 1979 fire.
Site
location. In detail: urban settlements, municipality limits
(in yellow the ones affected by the 1979 fire), main roads
of communication, and perimeter of the 1979 fire (in red).
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Physical
environment
Topography
The
area is located in a mountainous zone with varied topography:
the northern limit is formed by the Utiel-Requena plateau
and the Júcar river slopes. The West and South are bordered
by the Cofrentes, Channel of Navarrés and Enguera valleys;
within the area burnt by the 1979-fire, the Caroche mountain
(1,128 m) is the highest elevation. For the full Ayora test
site, the "Muelas" of Cortes de Pallás and Bicorp
are the most prominent landscape features. In general, the
elevation varies between 100 and 1158 m above sea level.
Elevation map (meters above sea level)
Apart
from the partially steep slopes towards the limits of the
area, especially towards the Rio Jucar in the North, most
of the surface is undulating with elongated valleys between
mountaineous areas of moderate elevations and slopes greater
than 50° only being present for 2% of the surface.
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| Digital
Elevation Model |
Typical
landscape of the Ayora region |
Climate
Rainfall
The
distribution of the precipitation in the area exhibits an
important spatial variation with annual averages ranging
from 350 to 700 mm along a West-East gradient.Besides
the spatial variability, there is also a great annual variability.
Especially for the years where large fires occurred, 75%
of all stations in the area showed an annual
precipitation of 75% below the average.
Records of annual precipitation (average from 22 stations
) during the period 1979-2000.
Temperature
The
average annual temperature varies between 13 and 18 ºC,
with a spatial variation similar to that of the precipitation;
the zones with lower annual temperatures are located in
the Southwest and correspond to higher elevations .
Bedrock
While
there is relative diversity within the different sedimentary
groups, 74% of the area is characterised by 3 general bedrock
types: limestone (33% ), dolomites (28%) and gravels (13%).
Additionally, clays (6%), marls (4%), sandstone (1%), silt
(4%), sand (5%), conglomerates (5%) as well as a number
of other bedrock types that account for less than 1% of
the total surface can be found.
Main lithological units of the Ayora region
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Land
cover / use
Over
the last 30 years the land use has greatly changed
in Ayora. Wildland is the most extensive land use, it accounts
for 67% of the total surface area but it is dominated by
shrublands, due to the great impact of forest fires and
the recolonisation of abandoned agricultural land.
Current main land use types
Forest
fires constitutes the main disturbance regime in the region
with strong effects in the landscape configuration. Since
1979, more than
120000
ha have been burnt, constituting more than 30% of the total
forest surface.
These
forest fires have altered the composition of the forest
surface, which previous to 1979 was dominated by Pinus
halepensis, Pinus pinaster and, to a minor extent, Quercus
ilex.
Distribution of the zones burned between 1989 to 1994.
At
present, shrubland and pine in regeneration (represented
mainly by Pinus halepensis) occupy most of the surface;
there are only tiny and isolated surfaces with the characteristic
wooded vegetation of the zone (Quercus ilex, Pinus pinaster
and Pinus halepensis).
Land
use types (excluding burned areas) and characteristic mixed
woody vegetation of the area
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Socio-economic
background
Population
The
Ayora area has 17.600 inhabitants, concentrated basically
in three urban areas (Ayora, Engera and Mogente). The average
population density is less than 14 inhabitants/Km2,
and 50% of the municipalities have even less than 10 inhabitants/Km2.
The
number of inhabitants in the area has decreased by 8% since
1979, since 1990 it shows a 15% reduction. This is similar
to other rural interior areas in Spain and is caused by
a variety of socio-economic factors, without direct relation
to the large forest fire of 1979 .
Land
abandonment
Following
the reduction of population, traditional agricultural methods
have widely been discontinued, particularly in the mountainoous
areas. Fields less suitable for intensive cultivation were
abandoned, and became colonised by natural vegetation (with
a great amount of fuel); nowadays, most of the cultivated
land is located in valleys where agricultural mechanisation
is possible.
Rural
constructions abandoned several years before
Approximately
10% of the lands cultivated in 1978 have been abandoned,
and this percentage is notably higer in the most mountainous
municipalities. Nevertheless, the Common Agriculture Policy
(CAP) for reforesting agricultural land has had a remarkable
repercussion in the region: of the entire Valencian Community,
Ayora, with 820 ha reforested, is the municipality with
the greatest number of agricultural lands reforested under
the Regulation (EEC) Nº 2080/92.
Marginal Lands reforested under the Regulation (EEC) Nº
2080/92
Legal
Framework
Land
ownership
The
1979 forest fire affected mainly private-owned forest surfaces,
in particular woodlands (54% of the total burnt area), which
implied large economic losses for the owners.
| |
Woodland |
Shrubland |
Total
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| Public |
25,3 |
7,7 |
33,0 |
| Private |
54,7 |
12,2 |
67,0 |
| Total |
88,0 |
20,0 |
100 |
Distribution
of the forest surface affected by the 1979 fire
based on the property and type of cover
The
fire caused a sudden increase in the supply of wood -
equivalent to more than 2/3 of the total wood produced
during the previous 10 years (1971-1981), which resulted
in a reduction of the price of wood with losses amounting
to more than 6.288.000 Euros . The commercialised burned
wood was made up by Pinus halepensis (80%) and
Pinus pinaster (20%); it was used for the production
of commercial packages, crushed paste, etc. .
Forest
legislation
The
Valencia Region has complete autonomy regarding forest
management. With this authority it has developped an
individualised norm that is complementary to those existinig
at the State and European Union levels. Within this
legislative framework, the Generalitat Valenciana established
a specific legal regime for forestlands in the Valencia
Region, with special emphasis on the protection and
improvement of forested lands and its externalities.
Specific norms have been developed to regulate different
aspects of forest management.
Among
the activities regulated with different rules and norms
are
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the
use of recreational facilities and vehicular circulation
in the Region’s forests
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the prevention of forest fires and procedures to follow
if a forest fire occurs
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the origin and quality of the reproduction materials
used for forest plantations
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the harvesting of mushrooms and fungi.
The
high prioritiy awarded to environmental issues in the
Valencia region is of great importance for the project,
because it indicates the acceptance of innovative new
management strategies for a sustainable use of resources
combined with a decrease of natural hazard risks .
Management
actions applied so far
A
number of management actions have been developed in
the area since 1979. They will be evaluated by a descriptive
analysis (location, techniques used, results obtained,
etc.), which will be complemented with specific samplings
in the field.
Selective
vegetation clearings have been applied in order to both
reduce fuel accumulation and reduce the competition
for resources by regenerating pines.
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Vegetation
clearing to eliminate fuel accumulation and pine
competition
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Fire
breaks and water reservoirs
The
Forest Fire Prevention Service is launching a Fire Prevention
Plan based on preventive silviculture, to both reduce
the forest fire propagation and facilitate the access
of burning areas for fire brigades. This project is
currently in the implementation phase and it will provide
a real execution project for GEORANGE application
and testing: this Plan has been designed as a network
of fire-breaks of variable widths and plant cover, based
on the area to be protected. For the maintenance of
these areas, the use of sheep grazing is planned.
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Forest
fire preventive actions: firebreak and water reservoir
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Management
Objectives
In
accordance with the major aim of the
GEORANGE project, the main objectives for the Ayora
area are:
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The
evaluation of the effects of past management actions
The
major goal of previous management efforts has been the
reduction of the fire hazard and to promote an increase
of the proportion of mature ecosystems. In order to
assess the effectiveness of these actions, the temporal
(past conditions and desired state) and spatial (landscape
scale) dimensions will be considered.The state of rangelands
will be assessed by a rule-basemaking use of different
parameters and variables, which will be provided on
a spatial basis by integrating field data with remote
sensing techniques.
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The
proposition of new management options
For
the Ayora test site, management strategies will be defined
that combine economic benefits with conservation issues
by supporting a sustainable use of rangeland resources,
while at the same time reducing the fire risk as much
as possible. With regard to the outstanding importance
of wildfires and their mitigation, one thread to be
followed by the project will be the modification of
the surface distribution of different types of fuel
to reduce the overall fuel load according to fire propagation
models.
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Unburned
vegetation patch
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Agricultural
area
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Research
Topics
Basic
description of the resources and the physical environment
The
implementation of a GIS for the Ayora test site includes
the compilation, standarization and update of cartographic
and alfanumeric databases. This information will be complemented
with new information from specific field monitoring and
remote sensing.
The
present layers of the cartographic data base are:
- Soil
types/bedrock outcrops
- Climate
- Land
cover/land use
- Vegetation
- Forest
fire recurrence
- Fuel
model
- Socio-economic
factors
This
database will be updated with specific rangeland indicators
that are to be collected for all the GEORANGE sites.
Characterisation
of the disturbance regime
- Fires:
Digitisation of the perimeters of all fires having occurred
since 1979.
- Land
abandonment: Evaluation on the basis of the agricultural
statistics and the temporal sequences of the satellite
images.
- Droughts:
Analysis of the historical series from the meteorological
stations to determine the recurrence and intensity of
dry periods
Post-fire
regeneration
- Regeneration:
Analysis of the regeneration patterns (plant cover, species)
and their spatial distribution (bedrock, aspect), by means
of field monitoring and remote sensing support.
- The
effect of unburned patches and their distribution
Types
of spatial distribution of unburned trees and regenerated
pines.
Fuel
assessment
- Fuel
models identification and distribution in space
- Fuel
dynamics
- The
effects of clearing practices
- Fire
breaks delimitation and fuel growth dynamics inside
Reforestation
monitoring
- Localisation
- Stand
growth dynamics
Effects
of landscape attributes, including fire-prevention measures,
on fire hazard
Parameterisation
of a fire propagation model.
Validation
of the model parameters for subsequent fires produced in
the test area.
Analysis
of various landscape scenarios (fuel load and spatial distribution,
firebreaks and so on), setting the same weather conditions
as in 1979 (situation of high fire hazard).
Deriving
management recommendations
Image
Gallery
Virtual
flight
The
flight simulations have been produced by draping a Landsat-5
TM image acquired in 1993 and geo-referenced using digital
elevation data over a Digital Elevation Model supplied
by the Spanish Centro Nacional de Informacion Geografica.
Please note the size of the respective files.
| Flight 1 (8,5 MB) |
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| Flight 2 (8,3 MB) |
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| Flight 3 (8,3 MB) |
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