Environmental Engineering Reference
In-Depth Information
(
Quercus robur
L.), ash (
Fraxinus excelsior
L.), white poplar (
Populus alba
L.) and
black alder (
Alnus glutinosa
(L.) Gaertn). A relict of the natural forest is represented
by the 200 year-old Bosco Siro Negri located within 1 km. The poplar high stand of
46 ha (Populus canadensis Moench, Clone I-214) was 12 years old in 2002, the
spacing was 6 6 m and the tree density was 278 tree ha
−
1
. The average tree height
was 26.6 m, while the average diameter at breast height (dbh) was 0.33 m and the
stem basal area was 20.5 m
2
ha
−
1
in 2005, when the site was logged. In order to carry
out replanting after logging, residues were removed, stumps were drilled to allow a
60 cm deep ploughing, and 4 m long shoots were inserted for about 150 cm into the
ground. In general, management intensity was low with removal of ground vegeta-
tion (mainly Artemisia and Poa) by harrowing during early summer and occasional
irrigation on demand. During 2002-2005 one fertilization event of 300 kg ha
−
1
of
urea occurred in May 2002, and two natural flooding events in November 2002 and
October 2004. Soils are Arenosols and Regosols not well developed on recent allu-
vial sand and gravel deposits of the Ticino river. Topsoil shows a bulk density of 0.9-
1.4 g cm
−
3
, the nitrogen and carbon content are 5.23 kg C m
−
2
and 1.36 kg N m
−
2
,
pH (H
2
O) ranges at 5.5-7.0. The soil texture is sandy-loam (60.4 % sand, 30 % silt
and 9.6 % clay). The climate of the site is classified temperate continental, with an
average annual rainfall of 912 mm and an average temperature of 12.5 °C. Budburst
usually occurs at the beginning of April and senescence in October, with the LAI
peaking at around 2.0 in July. Winds show a prevailing direction from the north-east
and south-west. Atmospheric nitrogen deposition is about 20 kg N ha
−
1
per year.
2.2.18 Pianosa (IT-Pia)
The Island of Pianosa (42.58437° N; 10.07804° E) is one of the seven islands of
the Tuscan Archipelago with a total area of 10.2 km
2
and a coastal perimeter of
approximately 20 km. The island is almost completely flat, with some small undula-
tions, its highest elevation is 29 m.a.s.l., while the average is about 18 m.a.s.l. On
the basis of a historical meteorological dataset (1951-2009), the average air tem-
perature is 15.8 °C and the average annual rainfall is 497 mm, ranging between a
minimum of 176 mm (1999) and a maximum of 716.2 mm (1984). A clear seasonal
precipitation pattern shows a maximum from October to December followed by a
decrease with a minimum value in July. The soils are sandy-loam or sand, alkaline,
rich in carbonates, with a moderate content of rock fragments, mainly classifiable
as Leptosols. Three main ecosystems have been mapped: abandoned crops and pas-
tures, Mediterranean macchia and woodlands. Abandoned croplands and pastures are
the main ecosystems in terms of extent (52 %) but are less representative in terms
of total biomass (26 %). The land previously used for agriculture is now covered
by a species association typical of degraded Mediterranean agricultural soils. The
Mediterranean macchia vegetation exists at different evolutionary stages as a con-
sequence of the progressive re-naturalization process which the island is currently
undergoing. The Island of Pianosa represents an interesting case study to assess the
evolution related to land use change in a Mediterranean environment, since the island
