Walker - 1967 - A geography of Italy

PART I I : SOME P H YSIC A L GEOGRAPHY
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is discouraged by the föhn and may be eliminated altogether (the upper Valtellina).
Without any clearly defined break the beech stratiun merges into the
conifers among which the noble red fir, with its reddish bark and long tight cones,
is a favourite with the forestry authorities. It shelters an undergrowth which
includes m3rrtles, rhododendrons, heather and a variety o f edible fungi. The
hardier larch is content with less favourable situations on northern slopes or
rocky ground. Although a conifer, it is not an evergreen; the shedding o f its
needles no doubt reduces the transpiration loss and enables it to struggle on in
insolation well beyond the limit o f the forests proper. It is sometimes accompanied
by the Pinus cembra whose survival is threatened because o f the popularity
o f its seeds with forest fauna. In the more continental Alpine interior the Pinus
sylvestris occupies exposed stony slopes where evaporation and the percolation
o f water defeat most other conifers.
Between 1900m and 2100m the habitat deteriorates and the forest thins out.
Only those trees and shrubs which can dispense with the protection o f their
fellows survive; six or seven months o f snow, a short growing period, fiierce
temperature fluctuations at ground level, strong desiccating winds and a soil
composed o f little but scree are all elements o f this daimting environment.
Among patchy thickets composed o f contorted mountain pines (P. montana),
junipers, rhododendrons, myrtles and alders (Alnus viridis) only the larch, the
pioneer o f the forest, stands erect; the rest cower over the rocks to escape
the wind and conserve warmth and moisture. Further up across the scree to the
permanent snowline only the humble Alpines survive; their long roots, hairy
leaves and cushion-like form help them to withstand violent temperature fluctuations
and excessive loss o f moisture.
THE VALLE PAD ANA. O f the vast forest o f the Valle Padana (Cisalpine Gaul
to the Roman colonists under whose axes it first began to retreat extensively)
practically nothing remains; the last sizeable remnant, the oaks o f Montello, so
long protected by the conservationist legislation o f the Venetian Republic, disappeared
in the 1890s. A reconstruction would probably reveal oaks(2 . robur and
Q.petraed) spreading down from the piedmont and dominant over most of the
plain. In response to local drainage conditions they would be associated with the
elm, ash, willow, alder and poplar. On the higher morainic arcs o f Piedmont,
especially where ferretto has rendered the crystalline detritus more impermeable,
a few stands o f chestnut and beech have survived, but this habitat is also proving
attractive to that vigorous foreigner the robinia.
Along the northern margin o f the plain, the fans o f very coarse fluvio-glacial
debris support a heath vegetation known generally as brughiere and locally in
Piedmont as vaude or baragge. Heather, gorse, silver birch and the Pinus
sylvestris are characteristic, this last the straggling rearguard o f a post-glacial
retreat. Traditionally the summer grazing grounds o f transhumant flocks, which
have contributed to the degradation o f the vegetation, the brughiere have dwindled
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