Fjölrit RALA - 15.06.2004, Síða 31

Environmental features and land use of Etna (Sicily - Italy)
C. Dazzi
Dipartimento di Agronomia Ambientale e Territoriale - Universitá di Palermo - Italy
Owing to its position, an isolated mountain in the middle of Mediterranean sea, to its shape
and size and to its activity which continue uninterruptedly since its eruption from the sea
approximately 550.000 years B.P., Etna is certainly one of the most important volcano of the
word and one of the most active (in the sense of “productive” and eruption frequency).
It is a complex strato-volcano, formed of lava flows altemating with pyroclastic materials,
emitted over various emptive areas which have, over centuries, built up the actual volcano.
Today Etna reaches 3315 meters above sea level, a huge triangular shape with its peak blown
off, where explosions at the summit develop into spectacular emptions. The gentle slopes
towards the base of Pleistocene clays, form most of the eastem third of Sicily.
The climate in the Etna area is basically Mediterranean but rainfall and temperatures are
affected by height, exposure of slopes, by winds and by clouds coming from the coast.
Temperature distribution is uniform around the volcano but rainfall is irregular. Moist winds
from the sea bring rain to the eastem slopes. The pedochmate show an udometric regime
ranging, according to altitude, from xeric to udic and a thermometric regime ranging from
thermic to mesic to frigid.
On the lower slopes of the south-westem flank the morphological features show alluvial
terraces, while there are marine terraces on the south-eastem flank. These may be interrupted
by sub-vertical escarpments which reach 200 metres in height and few kilometres in length.
Above 900 m altitude forests prevail, lava flows greatly influence the landscape and
produce morphologies with irregular, rough surfaces. Slopes get steeper with frequent abrapt
variations; some areas with gentle slopes and regular contours can be found. A peculiar
morphological feature are the numerous cones along the perimeter, they are the result of the
accumulation of the pyroclastic ejected.
Above 2000 m the very steep slopes reach the main craters. After the recent lava flows the
land has become a blackened moonscape.
The wide variation of soil types is due to the parent material, age, different morphologies,
climatic features and last, but not least, to exposure and to winds which carry and deposit ash
and lapilli which may be abundant.
These characteristics greatly influence land use and distribution of vegetation. The
following vegetation belts can be distinguished:
1. base to 900 m approx: the crop belt with many orchards of different fmits.
2. from 900 m to 1500 m approx: the woodland belt where forest vegetation prevails.
3. from 1500 m to 1800/2200 m: the mountain belt dominated by vegetation of high
Mediterranean mountains until the altitudinal vegetation limit which ranges from 1800
m to 2200 m a.s.l. according to exposure and morpho-climatic conditions.
In the crops belt, agriculture takes on very peculiar features mainly determined by the
physical characteristic of the landscape. Tree fmit cultivations characterize above all the
landscape of this crop belt owing to the wide surface that they occupy and for the peculiarity
of some of their productions. The most cultivated species both with specialized systems or in
promiscuous cultivation are: citmses, olives grapes, pistachio, apples, pears, cherries and
kemels. It is to outlined also the prickly pear cultivation and of others tree fmit cultivations
that show a marginal importance for the Etna area but that, as happens also for the strawberry
of Maletto and for the sub-urban horticulture supply local markets.
18