Portal de Periódicos da CAPES

Die Vegetation des Val Onsernone (Kanton Tessin)

1918; Nature Portfolio; Volume: 102; Issue: 2561 Linguagem: Inglês

10.1038/102243a0

1476-4687

Joh. Bär,

Plant Taxonomy and Phylogenetics

THIS is a very compact description of the vegetation of a mountain valley-basin south of the Alps, a little to the north-west of Lago Maggiore. The rainfall is high (80 in. to 100 in.), and is nearly all received during the summer. At the same time, the number of rainy days is low and of clear days high, so that a great deal of sunshine is received, and the winter temperatures are relatively high. Thus we have a combination of some of the favourable conditions for vegetation characteristic of an ”oceanic”climate with some of those characteristic of a continental one, a combination which, together with the great range of altitude (250 m. to 2500 m.) within the area, leads, to the occurrence of a very wide range of vegetation and a very large number of species. The vastly greater proportion of the whole area of 113 sq. km. is covered with trees and shrubs. The general alti-tudinal forest zonation on the northern exposures is chestnut, beech, silver fir, spruce, and larch, with the addition of extensive birch woods and more local lime and grey alder woods according to the soil conditions. Besides these there are extensive scrub associations of hazel, chestnut, birch, beech, and oak, which play an important part in the economy of the valley as pasture for goats, besides unpastured scrub of willow, alpine alder, alpine rose, juniper, etc., “heaths”of heather, broom, and bilberry, and numerous types of grassland. Many of the associations are almost identical with common British types. Above, these there is a wide selection of alpine types, and at the other end of the scale an association of the Mediterranean Cistus salyiifolius. The memoir is accompanied by an excellent vegetation map, in which the distribution of the dominant trees and shrubs is depicted by means of coloured symbols.