CookiesAccept

Questo sito utilizza i cookie e tecnologie simili.

Continuando la navigazione nel sito acconsenti al loro impiego. Per saperne di piu'

Approvo

Park entrance

 

A portal, made up of two heavy wooden doors, allows entrance to a path which leads up to the gorge of the Tinazzo. Passing through the woods, thanks to this easy access, one encounters a rock wall that seems to block the way. But on getting closer one will see a very high cleft in the rock. From here, over the centuries, hundreds of millions of cubic meters of sand and rock were carried down to the lake by the heady swirling  water of the River Borlezza. The deposition of this huge amount of debris allowed the formation of the peninsula on which the large factory of Lucchini RS was built.

A path was built in a territory that has experienced a millennia of endless battles between water and rock, shaped by ancestral glaciations and eroded by the flow of rushing waters of the river Borlezza. Two huge walls, higher than 40 meters, stand as wings at the entrance of the gorge which can be safely visited for more than 100 meters having a width which varies from 1 to 4 meters.

“And there they were, from the clefts of the cliffs in some long grasses, pushing their heads up towards the light, just lying there dead and dangling. Mosses and lichens clinging here and there and ivy trunks rising up, forged to the rock, unfolding a lush fan of green on the harboring walls lit by the sun.

And further up , old falling trunks and smattering of green vegetation dangling on the abyss and clusters threatened by the frost, ready to fall on the unlucky visitor…”

 Taken from the book   La gola del Tinazzo, written by Don Amighetti in 1897

 

Historical notes

 

The water of the Tinazzo has supplied, for centuries, the power needed to work the iron from the surrounding valleys and for which , both upstream and downstream of the gorge, many mills and forges were built.

Still, the gorge always was a permanent threat of devastation. During violent storms, waters would carry huge quantities of vegetation debris jamming the opening of the gorge entrance, creating a dam of logs able to increase the back stream surface level by 10 meters. When the dam would break,  the effect was devastating:  the force of water would enter the gorge with a deafening roar,  unloading itself on the lake and the village of Castro.

One of the most disastrous floods was surely the one that happened just before 1535. The scholar Achille Mozzi, from Bergamo, wrote in 1590  “Vicus Oliveri Castri Memorabilis olim, Corruit, immensae turbine raptus aquae”  (the village of Castro, once rich in olives groves and so fond of memories, was devastated by an immense water vortex).

But the flood on which Mozzi reminisces could have actually been another flood which happened in 1590, as many others were then remembered in 1692, in 1737, in 1820, in 182 and in 1905.

It was probably right after the devastating flood at the end of 500 that the mighty wall of the embankment towards Castro was built, already visible in maps of 1626  and still visible today.

The flood of 1784 seriously damaged the first attempt at transforming the economy through the industrial revolution, an economy which, for centuries, had craflty exploited the water of the gorge. The blast furnace which Ludovico Capoferri di Castro had built at the exit of the gorge was in fact razed to the ground.

The successors of Giovanni Andrea Gregorini, wishing to expand the industrial area and secure the plants from further destruction, were granted in 1915 the authorization to divert the course of the river Borlezza, which was made to flow through an artificial gallery near the Orrido di Castro.

Because of this, the final part of the gorge became silent and dry and the gorge itself transformed into a fossil as the original delta never again was fed by debris.

From the dawn of time, the natural barrier of the Gorge of the Tinazzo was an easily defensible and manned border.

The gorge thus was, for centuries, a strong element of spatial demarcation. At the beginning, it defined the border between the Roman Gaul  and the free tribes of the Camuni. During the Roman Empire it served as border between the Volturia and the Quirina tribes. Later on, it divided the Lombard duchies and the Episcopal principalities of Bergamo and Brescia. Today, still it represents the border between the diocese of Brescia and Bergamo and the  municipalities of Lovere and Castro.

Along this ancient spatial demarcation, in the XI century, the fortified harbor of Castro and the so-called Road of the Corna were built, the latter built into the rock at the top of the gorge.

Both the village and the road held a high strategical factor: they in fact allowed to connect, through the lake, the plain and the valleys which were subjected to the principalities of Bergamo,  without having to trespass into the hostile territory of Lovere, which used to belong to Brescia.

The high Valseriana and the Valle di Scalve were important manufacturers of iron and silver. Still, they depended on the plain and on the towns for food provisioning.

Along the way that from the Po plain leads to Val Camonica through the Val Cavallina, the final course of the Borlezza River and its gorge (the  Tinazzo) make a strong natural barrier.

The thick walls of the gorge, right after its beginning, connect together so as to create a natural bridge which, in ancient documents, was called pons terraneus (from which come the name Poltragno, a dainty place nearby). On such a natural bridge many armies passed by, including those of German emperors descending to Italy for their domination wars or for the pope coronation.

Among them there surely were Frederick I, Holy Roman Emperor in 1166, Ludovico il Bavaro in 1327, Charles IV in 1355 and Maximilian of Habsburg in 1516.

The deep gorge of the Tinazzo to the south of the bridge, and the swampy bed and the heady swirls of water of the Borlezza to the north, prevented crossing of the watercourse and the narrow passage could be easily blocked.

The medieval fortification of the Colle di San Lorenzo (the hill of San Lorenzo) was probably built upon an original Roman fort and had the task to monitor and prevent the passing of the Hills and the encirclement of the gorge to wade the river on its wide and below estuary.

The road of the Corna was built along with the fortified harbor of Castro at the beginning of the XI century to create a commercial lake way between the plain of Bergamo and the high Val Seriana, without ever trespassing into the hostile territory of Lovere, which back then used to belong to Brescia.

The road, which was supposed to be travelled by carriages, was built with an outstanding technical know-how, which had to overcome several natural obstacles by building high supporting walls and several difficult excavations into the rock. Wherever the road had the rock has a base, binaries were built to make the way safe, keeping on track the wheels of the means of transport. In its narrowest point, between the rock walls and the cliff, a huge fortification was built. It was made of a door (or port) that, militarily manned, should have protected the territory of Castro from the back.

Today, of such fortification just the two hinges remain which were destined to contain the door jambs

 

 

Park geology

 

The land surrounding the park is steeped in geological history, dating back to the formation of the embedded walls and ancient bed and the formation of Castro. Such rock, deposited back about 190 MA in a marine platform environment, looks chaotic and shows almost no sign of stratification. In more recent times, this same rock formation has been altered, as evidenced by the many traces of overlapping events, formative at first and then shaping due to the flow of rivers, karst development, and glacial actions. The gorge rock has undergone a long erosion process that has resulted in a narrow and stunning opening where traces of the progressive lowering of the river bottom and the heady swirl of waters are very visible.  On more than one level, one can see circular shapes called potholes, which are caused by erosion  as the fast flowing water swirls, carrying fragments of stones and pebbles which grind down the rock to form the pothole structures.

The limestone rocks show signs of karst especially along fractures and faults, while the chemical deposition of calcium carbonate had created wide and interesting travertine formations along the walls.

Important water circuits end their flow near two sources located within the park limits. Over a period of time between 2 million and 10 thousand years ago, the glacial action worked on this portion of the territory. Outstanding ice thicknesses have occupied the gorge over time.

Finally, through the canyon of the Tinazzo, water carried the debris that deposited in the basin of the Borlezza when the water reached the lake, forming the delta on which the metallurgical factory was built .

 

Park fauna

 

While not especially extensive  over a large area, the park offers several different environments that represent many settlement opportunities for the fauna, which is very different.  Here, one can find the typical inhabitants of the Pre-Alps such as the fox, the Beech Marten, the yew, the squirrel, the dormouse, the hare, the roe deer, the Eurasian jay, the pheasant and many passeriformes. The areas with its terraced lawns, many of which are used as olive groves with its favourable exposure to the south, have dry stone walls and overhanging cliffs  that are home for several species of reptiles, birds and butterflies.

The ravine woods, which precede the fossil gorge of the Tinazzo, is a habitat that has a high humidity  and a climate that in summer time is cooler than the surrounding area, while in winter is actually quite mild. There is a small stream here that comes from several sources. In this stream one can find the cray fish, a freshwater crustacean which has more or less disappeared from most of the European streams, threatened with extinction due to the environmental and water pollution, diseases and the competition of exotic species introduced by man. Streams, small brooks and ponds are also the ideal habitat for the fire salamander, which needs them for the development of their larvae. After metamorphosis and the developing of the yellow and black pattern they will abandon them and go back to living in the thick of the woods.

 

 

Park vegetation

 

While dominated by the amazing geomorphological landscape of the gorge, the small territory of the park, because of its complex morphology, the local climate, and the nature of its rock presents a stunning display of floral and vegetation interest.

The woods, in its complex composition of tree species (in which the Hop Hornbeam, Ostrya carpinifolia, ispredominant) and shrubby and herbaceous species, show some of the typical aspects of the ravine woods near the gorge where its darkness, the coolness, and humidity of the environment has favored a spontaneous settlement of yew (taxus baccata). Spectacular is the development of the Eurasian fern (Phyllitis scolopendrium), which covers the slopes of the woods.  On the limestone cliff the sky blue bellflower (campanula elatinoides) stands out, rare and precious in this hidden place, with its beautiful heart-shaped and velvety leaves. On the margins of a perennial stream the horsetail states its unmistakable presence with two species: the field horsetail  (equisetum avense) and the rough horsetail  (equisetum hyemale). It isn’t strange to have such biodiversity of plants with botanic entities such as the black locusts, Ailanthus, privets and even some palms of the Trachycarpus family, that are linked to a more or less anthropization which differs according to the park surface. Near the gorge, terraced shelves host old hay meadows, which in the past showed more multicolored blossoms. Even the bare rock walls are colonized by vegetation such as the light blue bell flower (campanula carnica), the queen grass (telechia speciosissima) similar to a huge yellow daisy, and the Horned Rampion (Phyteuma scheuchzert). The other parts of the park, exposed to the sun, host a sparse and low scrub dominated by the hop hornbeam, ashes (Fraxinus ornus ) and some English oaks (Quercus pubescens).

The doors left by the coverage of the woods have been colonized by the flora of dry grasslands where the sesleria, the most common graminaceous, is accompanied by several Mediterranean and steppe range species. 

Joomla Templates by Joomla51.com