The Lime Kilns and the production of Quicklime
The production of quicklime has been – for centuries – one of the necessary activities in order to realize a binder used for construction work, plasterwork and the painting of wall structures. Quicklime was produced in strategic places, usually near water courses or scree, where it would be possible to extract the calcareous material, or near a woodland where it would be easy to source the timber needed for the cooking process – as well as a road for the transportation of the material. The abundance of raw materials (wood; calcareous stones) explains the widespread presence of lime kilns in the region of Alpago.
A lime kiln is usually built against a slope, so that it is possible to access – from one side – the top part for the loading of limestone, and for looking after the cooking process; on the valley-side, the structure is equipped with three holes: the lowest one in order to extract the leftover ash from combustion; the one just above for loading the bundles of wood-sticks that feed the cooking process; the third – the highest one – would be closed off with stones and re-opened only once the cooking was over, for the extraction of the cooked limestone. The lime kiln is a barrel-shaped structure, with a variable width between 2-3 m of diameter by 3-4 meters of height – or even more. In the structures that are existing over this territory, we can see one or more of these holes still open, which – however – do not allow us to understand clearly what would have been the complete system for operating the kilns.
The phases of cooking in a lime kiln were as follows: 1) the preparation of the bundles of sticks of beech or spruce: around 100 kg of wood would be needed in order to obtain a similar amount of quicklime (that is, around 4,000 bundles with a diameter of 30-40 cm each and about 1 m of length); 2) the preparation of a vault in limestone that separates the oven from the upper part: the making of this structure was the most delicate task, and the structure was realized by specialists in this field, by putting close stones so to form a dome (or vault); 3) the locating of the calcareous stones used as raw material, which must be stoked from the top by starting with rocks of bigger dimensions, and must gradually decrease until the summit, which must be filled with material of smaller dimensions, up to 10 cm; 4) closure of the summit with a rough dome, made of minute stone chipping and a layer of about 10 cm of quicklime to be sealed off, while taking care to leave some holes to allow air circulation and discharge of the combustion fumes (by creating a forced draught); 5) closure of the upper door, leaving a hole free for the extraction of the ashes and a superior aperture for the loading of the bundles of sticks; 6) lighting up and fueling of the lime kiln: the cooking operations would last on average 5-6 days, 24 hours a day; on the first day one would load 2 or 3 bundles of sticks every 10 minutes; in the following days 8 to 10 bundles would be added every 10 minutes, and after 2 or 3 firings, one must take care to empty the leftover ashes; the bundles of sticks must be stoked with a fork by placing them against the perimeter of the lime kiln, so to dispose them in the shape of a dome, while leaving the central section free – so to produce a forced air draught; 7) when fully operative, the lime kiln would reach a temperature of 800-1000 C, thus allowing the disassociation of calcium carbonate into calcium oxide and carbon dioxide (CaCO₂ ➝ CaO + CO₂), and the production of quicklime (CaO); 8) after 2 or 3 days one would leave the lime kiln to cool down, and undo the stones that closed the upper door; one would then proceed with the download of quicklime; the rocks, at that point, would be friable, and their weight reduced by a third; 9) quicklime was then transported to the places where it would be worked; there, it would be immersed in large tanks and be made to slake with water; the chemical reaction is of an eso-thermic type – as it produces heat – and is expressed by the following formula: CaO + H₂O ➝ Ca(OH)₂, thus producing slake lime (or hydrate lime); 10) slake lime has a creamy texture, and in old manuals one was advised to leave it to set in decantation basins for at least two years (in order to complete de-hydration), before using it for building purposes.
Slake lime, when opportunely mixed and kneaded with sand, gives the classical binding substance that has been used for centuries for the construction of stone walls, or on its own – simply diluted with water – as a highly effective disinfectant paint (known as ‘whitewash’). The lime kiln at Pian Formosa – and the other ones mentioned here – witness the spread of these artifacts in the region of Alpago; they are mostly found, as it is logical to assume, along the strip of land at the foothills – where the raw materials (wood, calcareous stones) were more readily available – but examples are not missing along the Lago di Santa Croce too (where limestone is particularly abundant), or along the track to the church of Madonna del Runal, serving the needs of the community of Farra d’Alpago.
The Mugolio (Pinus mugo)
The essential oil obtained from Dwarf Mountain Pine (Pinus mugo) is an admixture composed of mono-therpenic hydrocarbons such as alfa- and beta-pinene, limonene, phellandrene, camphene, borneole and other substances. Its composition is not constant, and it is considered to be strictly connected to the geological substrate over which the individual plants grow. In particular, according to what reported by several sources, following several experiences of distillation – which have taken place, in the past, in different parts of the Alps – it is believed that plants coming from a siliceous substrate are richer in lemonene: a substance that is very much appreciated, as apparently it makes the oil more delicate. Traditionally, mugolio finds its use as antiseptic, balsamic and secretolithic (expectorant) for the respiratory system – besides being used as an analgesic in the case of intestinal pain and as an anti-inflammatory against arthritis and rheumatism. In the field of modern aromatherapy, instead, are particularly appreciated its anti-stress qualities.
Pinus mugo is an evergreen shrubby conifer that grows generally at high altitude, where it occupies the transitional band between ‘proper’ woodland and the Alpine meadows. It reaches a height of about 2-5 m, and the branches have an ascending habit of growth. The needles are gathered in groups of two; the sessile cones have delicately pointed (‘mucronate’) scales (‘squama’), with a central umbo. The plant is, generally speaking, dioecious (i.e. with separate male and female specimens). Its distributional area (‘areal’) is limited to the boreal hemisphere – more precisely Eurasia, where it remains confined on the main mountain ranges of Central-southern Europe, with a fragmented distribution and stations that are often separate and quite far apart from one another. In Italy it is present in the eastern Alps – from the Alpi Orobie in Lombardy to the Julian Alps in Friuli – with isolated nuclei on the Northern, Central and Southern Apennines also. Described habitually as a species connected to carbonated substrates, in reality Pinus mugo can live and prosper also on a siliceous substrate. Dwarf Mountain Pine formations are connected to particularly delicate and sensitive environments, whose existence often relies on the maintenance of traditional agricultural practices – such as high-Alpine pasture grazing and forest management. Pinus mugo formations are under the protection of the “Natura 2000” network, which lists important habitats whose conservation is considered a priority at EU level.
The mugolio takes its name from an etheric distillate derived from Pinus mugo. This product was once quite renowned in the area of Alpago – and in the province of Belluno in general – as in 1925 a Milanese society created a distillation plant in Lamosano (municipality of Chies d'Alpago), in the vicinity of the Tesa stream (near the wooden pedestrian bridge that linked Lamosano with Tarcogna). The branches of Pinus mugo were cut and collected in the Val Salatis, and were then conducted with a sleigh (known as ‘caroza’) until the locality of Col Pezei, upstream of the actual Casera Pian de le Stele (described in more detail below); from there, they were transported – by way of a 8 km long zip-line – to the distillation plant in Lamosano. This activity employed around 30 seasonal workers for about ten years, but as there wasn’t a prudent management of the resource (such as programmed cuts with renovation), the plants of Pinus mugo were progressively reduced, and the plantations exhausted, thus causing the closure of the plant, and forcing the activity to move to Cimolais, in the Dolomiti Friulane (where it was managed by two brothers from Alpago); at a later stage the distillery moved to Auronzo di Cadore.
The distillation plant contained two large metallic tubs, inside which were loaded the branches, then broken up and minced; these tubs were subjected to indirect heating for about 6 hours, thus provoking the evaporation of the substances that, once precipitated and cooled down in the apposite containers, were then separated (once returned to the liquid state, the essential oils float on the water). Once conveniently filtered, the oil thus produced could finally be bottled, ready to be marketed. This procedure could be cyclically repeated, by emptying the tubs and loading them up again with new raw material to be distilled. Finally, the waste product of this procedure could be recycled by the inhabitants of Lamosano, who would use it to feed their ovens; currently, it is being employed again to heat up the tubs.
The Production of Wood Charcoal
In the Alpago basin – as in other valleys of the province of Belluno, wherever there are beech woodlands (Zoldano, Vajont valley, Feltre area) – the activity of wood charcoal production has been carried out for centuries. Charcoal was produced mainly in order to feed the forges (or smithies) and the furnace kilns. Charcoal was being employed by blacksmiths, farriers and all those that – for some reason – had to work red-hot iron. In the Belluno area, through the centuries, have developed – and have later been dismissed – various productive areas of this type: along the Ardo stream in Belluno itself – during the Renaissance –; in the Zoldano, in order to feed the smithies for iron work at the end of the 1800s; in Alpago until the 1950s, as charcoal was requested by the armies in times of war, or for various other trades towards the valley floors and the plains. The production of wood charcoal took place near beech woods, where it was easier to gather the branches and trunks, already cut in slats, in order to build the poiàt (or charcoal kiln).
As an alternative, production would happen in situ in areas where larch and Dwarf Mountain Pine (Pinus mugo) abounded, and in other locations at high altitude, where wood was not of such great value as it was crooked, twisted by the wind or with double tops, and therefore not apt for the more traditional – and profitable – uses. The traditional poiàt (charcoal kiln) was a semi-circular domed structure, created by placing the split trunks – about 1 m long – round a central chimney known locally as rocchina or caneggio. One would then proceed by making the circle wider and keep adding wood – piling it up sometimes also in double or triple rows. In the more external layers one would have to heap thinner and thinner branches. Once terminated the stacking of wood, one would then proceed to cover it up with the ‘dasa’ (spruce branches or beech sprays and grass tufts or heather clumps) – so to be able to seal the pile. Above this layer would then be placed an earth layer that would cover the wood pile perfectly, so that a combustion for lack of oxygen could take place in the interior. The central chimney would then be stacked with short pieces of split timber, as well as straw, up to a middle height; to this would be added pieces of so-called ‘bronza’ (embers), which were needed in order to trigger combustion. The poiàt would then be closed off and sealed, as was the rest of the surface. The wood/charcoal yield was estimated to be in the ratio of about 1:3 (one to three); that is, roughly 30-35 quintals of wood would be needed in order to build a poiàt. A normal poiàt that produced about 10-12 quintals of charcoal would give a yield of around 30-40 bags. They would weigh up to 30-35 quintals, so to allow successive transportation to the valley floor. The areas where a poiàt could be erected are still visible in many woodlands of the province of Belluno and at the foothills of the Pre-Alps; they are recognisable to a trained eye for the circular shape of the clearings, as well as for the presence of a rather black earth, rich in charcoal waste, that would remain in the soil unused.
How was a poiàt being built: 1) First, one would need to prepare the clearing where the charcoal pit (poiàt) would be erected: at first, it was necessary to take the grass away, by eliminating also the earth layer for a depth of about 20 cm, and then compact the bottom well. The earth, once taken away and heaped outside the clearing, would be used to cover the poiàt; 2) around the chimney, would then be stacked the timber quarters, taking care to avoid leaving too wide interstices between the pieces of wood; one needed in fact to prevent air from filtering too easily inside the poiàt; 3) the last timber layer was formed of branches of smaller diameter, with the function of better blocking the spaces between the pieces of wood, while at the same time regularizing the shape of the poiàt; 4) the first layer was constituted of spruce sprays, with the function of damp-proofing and offering protection towards the rain and outside humidity, while at the same time providing a good foothold to the earth cover; 5) the second layer was formed by earth that had the function of suffocating the flame and prevent air from entering inside the poiàt (combustion chamber); 6) above the entrance (mouth) of the chimney would then be lit a fire that must be continually fed with pieces of timber, until filling up the chimney-stack; the opening to the latter would then be closed off with twigs and earth, and the carbonization process could finally begin (through the loss of volatile substances contained within the wood). The carbonization process (or charring) must then be constantly regulated through the opening of apposite apertures in the earth cover; these served as blow-holes for liberating the combustion fumes, and would therefore control the carbonization process, as they progressively opened towards the bottom of the poiàt; 7) once the ventilation holes had been opened at the bottom, and after letting them smoke off abundantly, the carbonization (charring) process terminated, and one would then begin to break up the earth layer, in order to uncover the charcoal; with a dedicated tool (a rake with large tooth), the charcoal pieces would then be extracted, gathered, and separated from the earth. The charcoal would be subdivided into small heaps, in order to let it cool down; it would then be loaded in jute bags weighing around 30 kg, and finally transported to the valley floors for consumption and/or to be traded.
A General Outlook on the Val Salatis
Through this action the GAL (‘Group of Local Action’) “Pre-Alps and Dolomites” intends to enhance rural tourism in the area through the betterment and strengthening of certain routes. One intends to propose tourists a qualified and well-equipped form of access to places of interest, able to offer a privileged point of view on elements of natural, artistic and cultural-historic value, and thus communicate – at the same time – the identity and traditions of the territory of the province of Belluno.
The use of pasturelands: the pasturelands at the end of the Val Salatis are used for cattle grazing. Near there is the building of Casera Pian de le Stele, and the remains of a moltrìn (an ovoidal precinct, in which sheep were kept, to be milked or sheared by the shepherds) can also be seen. Pastureland species in that area include: Common Kidney Vetch (Anthyllis vulneraria), Common Bird's-foot Trefoil (Lotus corniculatus) and the Ragwort Senecio abrotanifolius.
Flora: species in the beech wood acidophilus understory comprise Alpenrose (Rhododendron ferrugineum), Cowberry (Vaccinium vitis-idaea) and Blueberry (V. myrtillus). Among the noteworthy flora of the scree and of the mountain tops are: Silvery Crane's Bill (Geranium argenteum, this species can be found on the summit of Monte Cavallo, 2.251 m), Alyssum ovirense (present with only one isolated station on Monte Castellaz) and Asplenium fissum (a small fern that vegetates on the carbonated scree present on the orographic right side of the valley).
The Roundtrip of the Val Salatis
This roundtrip develops along the route of the Val Salatis until the locality of Pal – a point from which one branches off on an easy route across the scree at the base of the rock faces – to then reach Pian Formosa, from where one can return to the starting point via a path immersed in the beech wood (in the area of Malga Cate). From Pian Formosa, in a few minutes, one can also reach a famous century-old beech specimen, included among the monumental trees of the province of Belluno. This trail is easily accessed, and it offers interesting panoramic views towards the central basin of Alpago, with the Lago di Santa Croce in the distance. The two agriturismo at Pian Formosa and Malga Cate are fundamental stops along the itinerary, and offer excellent propositions in terms of local produce – besides the possibility of a tranquil stay.
Flora: Drooping Bittercress (Cardamine enneaphyllos) is a very frequent species of beech woodlands, with a spring-flowering habit; Sycamore Maple (Acer pseudoplatanus) is a tree that produces light seeds and propagates easily in the meadowlands or abandoned pasturelands; Alpine (or Purple scented) Cyclamen (Cyclamen purpurascens) is also a typical species of beech wood understory.
The Route to Caotes
Another itinerary unfolds along forest roads inside the beech woodland that covers the whole area, reaching the locality of Caotes. Here one can admire and enjoy a characteristic rural hamlet with its buildings (‘casere’; dairy pens), and rich pasturelands with their typical Alpine flora. Rising along the trail one then returns to Malga Cate, where we set out from in the first place. This itinerary – besides an agriturismo in the area where the trail starts – offers two parking areas equipped with barbecues, which are at disposition of whoever wishes to enjoy a picnic in the open.
Flora: Black Alder (Alnus glutinosa) can be observed at the margin of ditches and in other areas with stagnating water, Dogrose (Rosa canina) is present in the abandoned pastures and other marginal areas between pastureland and woodland, Woolly Thistle (Cirsium eriophorum) is an invasive thorny species also typical of pasturelands. In the area can be seen some grazing Yak too.
In Mountain Bike on the Cansiglio Plateau
An itinerary has also been devised to offer a comfortable excursion with the mountain bike, crossing the most panoramic – and of major environmental value – places of Alpago. Starting from the magical Cansiglio plateau, one crosses at first the beautiful forest to finally reach Pieve d’Alpago, skirting the foothills of Alpago. Along the trail one will meet several agriturismo, breeding farms of the typical Alpago sheep, monumental trees and equipped parking areas in support of the people taking the excursion. This route develops at the ideal ‘high line’ of 1,000 meters, almost completely on tarred roads that are nonetheless mostly devoid of traffic. The difference in altitude is negligible. It is an ideal itinerary for all ages and abilities; a shuttle bus service is also available on request for whoever wishes to return quickly.
The Malga Pian Formosa
The Malga Pian Formosa (1,220 m) is situated at the foot of Monte Messer (2,230 m), and is part of the Gruppo Col Nudo (2,472 m)-Monte Cavallo (2.251 m), over which also passes the Alta Via (‘Alpine Highway’) No. 7. It is situated near the entrance of the Val Salatis, and is also a few km away from the historic Cansiglio forest. The malga has a surface of about 60 hectares, with a vast area mostly dedicated to pastureland; here are raised sheep, cattle for meat and milk, deer, fallow deer, mouflon and courtyard animals. By booking only, one can also get a chance to taste the famous Alpago lamb and the local venison, produced by the malga itself. Generally, the malga is open from the second half of June to the first half of September.
The Alpago Sheep
The Alpago sheep is an autochthonous breed of sheep, sharing probably a common origin with the Lamon sheep. It is bred in flocks of small dimensions, with a semi-resident sedentary system, characterized by winter stabling and summer grazing, both on the valley floor and in high altitude pastures. It is a highly rustic animal, with a small-medium size, and a maximum weight of about 50 kg in an adult; the prolificacy is of 1,5 lambs for each sheep, with specimens that – when fully grown – weigh an average of 15-20 kg. One can obtain around 2,5-3 kg of wool every year from each head.