The slope of a water-course determines the speed of flow and, consequently, its ecological characteristics. These characteristics also depend on the temperature, the oxygenation and the chemical composition of the water. The presence of certain animal species and the settlement of vegetation species depend on these factors. The morphologic characteristics of the Franscinone (stony bottom, presence of puddles with more or less calm water) and its oxygenated and clean waters create different environments suitable to the life of many water-borne insects. In particular we can find larvae of the Common Mayfly, the Caddis fly, and the Stonefly.
The Franscinone also hosts Mites, Leeches, and Hairworms, which can reach a length of several dozens of centimetres. A typical inhabitant of this environment is the Fire Salamander which, like all amphibians, is under serious danger of survival due to men's environmental interference. The interception and polluting of the water, the embankment and channeling of streams and the use of them as a dumping ground, have put the life of the Fire Salamander in great danger, as its life closely depends on its environment.
In the waters of the Franscinone we can also find the Brown Trout. Along the stream, beside the stony outcrop, at the second stop, we can observe a few. In particular we can observe boulders of Gneiss of the Ceneri. These are the so-called erratic boulders, deposited by the glacier and originated in other areas, mainly from the Ceneri. These boulders are the oldest of the Canton of Ticino and can be more than 500 million years old.
Differing from the Gneiss of the Stabbiello, which is of a reddish colour and foliated, the Gneiss of the Ceneri is grey and has a compact structure. There are also many boulders of dolostone, of a light colour, which caved in from the Denti della Vecchia. The dolostone is a sedimentary rock (cf. stop no. 23), made of magnesium carbonate and of calcium.
In the past, there were no woods in this area: a canal flowed through here, and it carried the water towards the mills lower in the valley. There were also some pools used for hemp maceration: hemp was a very common plant used in fibre cultivation, later replaced by synthetic fibres. Therefore, also in this area the structure of the wood is very young. The broadleaves we find here are the same as the ones we saw at the second stop. Whilst among the herbaceous plants, we can see: the Astrantia Major, which flowers in July, the Herb Paris, typical of the river's banks, and the Lords-and-ladies, with its particular red fruits, set like a corn-cob, which ripens late in the summer.
The Historical Sonvico Nature Trail
Stage 1: Well and "Riaron"
Stage 2: House of Reason
Stage 3: Graad
Stage 4: Cassinel
Stage 5: The mixed broadleaf woods
Stage 6: Geological oddities
Stage 7: Mill and bridge
Stage 8: The glade in the wood
Stage 10: Wash-house
Stage 11: The birds of the wood
Stage 12: The eroded valley of the Franscinone
Stage 12: Water and energy
Stage 13: The edge of the flood-level wood
Stage 14: Dairy farm for the processing of milk
Stage 15: Lime-kiln
Stage 16: The rural area
Stage 17: The Humid area of Canéed
Stage 18: The earth kiln for charcoal production
Stage 19: Terracing
Stage 20: Madonna d'Arla
Stage 21: The Chestnut Wood of Pian Piret
Stage 22: The Beechwood
Stage 23: The Boulder with Engraved Cupels
Stage 23: I Denti della Vecchia
Stage 24: R’Alborón
Stage 25: The Oratory of S. Martino
Stage 26: The old center of Sonvico
Stage 27: The Walnut Press
Stage 28: The Church of Saint John the Baptist
The Luganese Regional Bus Line covers the Lugano – Sonvico stretch; from Val Colla you can reach Sonvico, using the postal bus from Tesserete to Sonvico.