Climate, Climate Variability and Impacts in the Mediterranean Area: An Overview
47
soil respiration and 0.1 mg CO 2 m,2 S,I flux at 2.7 m height in the atmosphere have
been measured. This results in a daytime net assimilation of about 0.34 mg CO 2 m,2
S,I or 12.2 g CO 2 m 2 d l . The modelling of the net assimilation for the year 1995
resulted an annual average of approximately 20 g CO2 m 2 day-I with val ues up to 50
g CO 2 m,2 day-I near day 140 and 30 g CO 2 m 2 day-I around day 220 but with a dip
down to 12 g CO 2 m,2 day-I around day 165 when the herbs were cut and the LAI
went down to zero for a few days. Atthe day 247 (1 September) the assimilation was
according to two different models 12.4 respectively about 23 g CO 2 m 2 day-I which
is for the first model very close to the value of 1997 (Cal vet, 2000). The annual
assimilation equals in the average about 7.3* 10 4 kg CO 2 halyearl (or 20 t C ha,l
yearl according to Cal vet 2000) which points at a very efficient ecosystem. Without
the cutting even more could have been be expected.
5.3 Forest Fires
According to Moreno (1999) in Spain the number of fires increased rapidly after
1973 from 4 000 to a maximum of over 25 000 in 1995 and the burned area jumped
up from about 5 000 to sometimes over 400 000 ha/year with large interannual
variability. In 1993 the number of fires was 15000 and 100000 ha burned. In 1986
there have been 12 000 fires and 500 000 ha burned. The average burned surface per
year presently is about 250 000 ha/year in Spain, 140 000 ha in Italy (prior to 1977
less that 70 000 in the average), 25 000 in France, 50 000 in Greece, and 90 000 in
Portugal. In North African countries but also in Turkey the burned area per year is
much smaller, e.g. around 20000 - 30 000 ha/year in both Algeria and Turkey.
Between 1989 and 1992 the total number of fires in the northern Mediterranean area
seems to have been fairly constant at 60 000 per annum but the burned area
decreased from 700 000 to 400 000 ha (Parry 2000).
Velez (1990) counted 173715 fires in Spain between 1974 and 1994 and 4.6
Mha were burned. 41 % were forests (33 % Pinus. a minor fraction Quercus), the
rest treeless scrubland or afforestation areas in the East. 3.3 % may be caused by
lightening. The financial losses are of the order of 300 M€ per year and the expense
for fire fighting 310 M € per year.
Wildfires are favoured by long dry and hot periods. They are as far as it is known
only to 3.3% caused naturally such as by lightning. Another 2.5% results from
management burning which are fires that escape if pasture or agricultural material
is burned. Conese et al. (1999) investigated 140 fire events which took place at the
western third of the island of Elba and determined the "risk level" for different
ecosystems ranging from 8 for chestnut forests to I for pasture. Meteorological
conditions have to be considered in addition. Lopez-Bermudez et al. (1999) reported
a case in the Murcia region where after three years of extreme drought in 1994 a fire
developed at air temperatures higher than 48 'c and strong winds with a fire front
of 50 km and burned 29 000 ha.
Pinus species are easier inflammable then Quercus species and once burned do
not recover from the roots (such as olive trees do) but only from seeds. Schultze-
47
soil respiration and 0.1 mg CO 2 m,2 S,I flux at 2.7 m height in the atmosphere have
been measured. This results in a daytime net assimilation of about 0.34 mg CO 2 m,2
S,I or 12.2 g CO 2 m 2 d l . The modelling of the net assimilation for the year 1995
resulted an annual average of approximately 20 g CO2 m 2 day-I with val ues up to 50
g CO 2 m,2 day-I near day 140 and 30 g CO 2 m 2 day-I around day 220 but with a dip
down to 12 g CO 2 m,2 day-I around day 165 when the herbs were cut and the LAI
went down to zero for a few days. Atthe day 247 (1 September) the assimilation was
according to two different models 12.4 respectively about 23 g CO 2 m 2 day-I which
is for the first model very close to the value of 1997 (Cal vet, 2000). The annual
assimilation equals in the average about 7.3* 10 4 kg CO 2 halyearl (or 20 t C ha,l
yearl according to Cal vet 2000) which points at a very efficient ecosystem. Without
the cutting even more could have been be expected.
5.3 Forest Fires
According to Moreno (1999) in Spain the number of fires increased rapidly after
1973 from 4 000 to a maximum of over 25 000 in 1995 and the burned area jumped
up from about 5 000 to sometimes over 400 000 ha/year with large interannual
variability. In 1993 the number of fires was 15000 and 100000 ha burned. In 1986
there have been 12 000 fires and 500 000 ha burned. The average burned surface per
year presently is about 250 000 ha/year in Spain, 140 000 ha in Italy (prior to 1977
less that 70 000 in the average), 25 000 in France, 50 000 in Greece, and 90 000 in
Portugal. In North African countries but also in Turkey the burned area per year is
much smaller, e.g. around 20000 - 30 000 ha/year in both Algeria and Turkey.
Between 1989 and 1992 the total number of fires in the northern Mediterranean area
seems to have been fairly constant at 60 000 per annum but the burned area
decreased from 700 000 to 400 000 ha (Parry 2000).
Velez (1990) counted 173715 fires in Spain between 1974 and 1994 and 4.6
Mha were burned. 41 % were forests (33 % Pinus. a minor fraction Quercus), the
rest treeless scrubland or afforestation areas in the East. 3.3 % may be caused by
lightening. The financial losses are of the order of 300 M€ per year and the expense
for fire fighting 310 M € per year.
Wildfires are favoured by long dry and hot periods. They are as far as it is known
only to 3.3% caused naturally such as by lightning. Another 2.5% results from
management burning which are fires that escape if pasture or agricultural material
is burned. Conese et al. (1999) investigated 140 fire events which took place at the
western third of the island of Elba and determined the "risk level" for different
ecosystems ranging from 8 for chestnut forests to I for pasture. Meteorological
conditions have to be considered in addition. Lopez-Bermudez et al. (1999) reported
a case in the Murcia region where after three years of extreme drought in 1994 a fire
developed at air temperatures higher than 48 'c and strong winds with a fire front
of 50 km and burned 29 000 ha.
Pinus species are easier inflammable then Quercus species and once burned do
not recover from the roots (such as olive trees do) but only from seeds. Schultze-