Ceresole Reale forest: mushrooms among the giants of the graian alps

Ceresole Reale forest: an ideal ecosystem 

Geography and location of the Ceresole Reale forest

The Ceresole Reale Forest extends within the territory of the eponymous municipality, in the province of Turin, at altitudes between 1,500 and 2,600 meters above sea level. Located in the northern part of Gran Paradiso National Park, this forest covers an area of about 400 hectares and represents one of the last examples of primary Alpine forest in Piedmont. Its particular geographical location, protected by the surrounding imposing mountains, creates a unique microclimate that favors the development of lush and diverse vegetation.

The slope on which the forest develops is primarily exposed to the northwest, a characteristic that significantly influences the local microclimate. The north-western exposure indeed guarantees less direct insolation during the summer months, reducing evaporation and maintaining constant soil moisture even in the hottest periods. This condition is particularly favorable for the development of fungi, organisms that require a certain degree of moisture to complete their biological cycle.

Geomorphological characteristics of the territory

From a geomorphological point of view, the Ceresole Reale Forest rises on a predominantly calcareous-dolomitic substrate, with the presence of schists and gneiss in some areas. This lithological variability contributes to the diversity of soils and, consequently, to the richness of different fungal species. The slopes are characterized by a moderate incline (30-50%) which favors water drainage without causing excessive erosion phenomena, thus maintaining a sufficiently thick humus layer rich in nutrients.

The forest soil presents particular characteristics due to the decomposition of forest litter. The humus that forms is of the "mull" type, characterized by rapid decomposition of organic matter and intense microbial activity. This type of humus is particularly favorable for the growth of saprophytic fungi and mycorrhizal fungi, which benefit from the richness of available nutrients.

Climate and microclimate of the forest

The climate of the Ceresole Reale Forest is typically Alpine, with harsh winters and cool summers. However, the particular orographic conformation creates local microclimatic conditions that mitigate climatic extremes. The average annual temperature is around 5°C, with average values of -5°C in the coldest month (January) and 15°C in the warmest month (July). Precipitation is abundant, with an annual average of 1,200-1,500 mm, well distributed throughout the year with a spring and autumn maximum.

Autumn rainfall represents a crucial factor for fungal fruiting. The months of September and October, with their frequent precipitation and still mild temperatures, create ideal conditions for the appearance of the most prized fungal species. The fog that often envelops the forest in the early morning hours helps maintain high relative humidity, above 80% for most of the day, a further element favorable to the development of fruiting bodies.

Vegetation of the Ceresole Reale forest

The dominant tree species

The Ceresole Reale Forest is characterized by a mixed conifer formation, with predominance of larch (Larix decidua) and Norway spruce (Picea abies). These two species represent about 80% of the total tree cover, while the remaining 20% consists of Swiss pine (Pinus cembra), silver fir (Abies alba) and, in the lower areas, beech (Fagus sylvatica).

The larch, in particular, is the symbolic tree of this forest and reaches monumental specimens, with some individuals exceeding 30 meters in height and 2 meters in diameter. These centuries-old giants, some over 400 years old, host a variety of specialized lignicolous and mycorrhizal fungi. The particular relationship between the larch and some fungal species like the Larch Bolete (Boletus elegans) and the Larch Suillus (Suillus grevillei) is one of the most fascinating examples of mycorrhizal symbiosis in the Alpine environment.

Distribution of tree species by altitude

The forest's arboreal composition varies significantly depending on altitude. In the lower belt (1,500-1,800 m a.s.l.), mixed formations of Norway spruce and silver fir predominate, with sporadic presence of beech. Rising in altitude (1,800-2,200 m a.s.l.) the larch becomes progressively more abundant, forming sparse and bright woods. Above 2,200 meters, the larch associates with Swiss pine, forming the so-called subalpine "forestina", characterized by shorter, contorted individuals.

The undergrowth and accompanying flora

The undergrowth of the Ceresole Reale forest is characterized by a rich herbaceous and shrub flora that varies in relation to the density of the tree cover and altitude. In clearings and more open areas, bushes of bilberry (Vaccinium myrtillus), raspberry (Rubus idaeus) and alpenrose (Rhododendron ferrugineum) dominate. These species, particularly bilberries, establish mycorrhizal relationships with numerous fungi, creating specific microhabitats.

In more shaded and humid areas, the undergrowth is dominated by ferns, mosses, and lichens, which create an even more humid microclimate favorable to the development of particular fungi like species of the genera Mycena and Galerina. The presence of abundant decomposing organic material (dead wood, conifer needles, leaves) guarantees a constant supply of nutrients for saprophytic fungi.

Mushrooms of the Ceresole Reale forest: a heritage of biodiversity

Mycorrhizal fungi: the symbionts of trees

Mycorrhizal fungi represent the most important component of the mycocenosis of the Ceresole Reale Forest. These fungi establish symbiotic relationships with tree roots, exchanging nutrients and water for carbohydrates. The specificity of these relationships varies from species to species: some are generalists, others are strictly linked to a particular host.

Mycorrhizal fungi of larch

The larch hosts a particular fungal community, composed of specialized species that rarely associate with other conifers. Among these stand out:

Suillus grevillei (Larch Bolete): characteristic mushroom with a sticky cap of bright yellow-orange color, yellow pores and stem. Grows exclusively under larches between July and October. Edible after cooking, but of modest quality.

Boletus elegans (Elegant Bolete): similar to the previous, but with a darker cap and smaller pores. This species is also strictly linked to the larch and fruits in the same period.

Tricholoma psammopus: medium-sized mushroom with a gray-brown cap and club-shaped stem. Edible species of fair quality, common in mature larch stands.

Mycorrhizal fungi of norway spruce

Under Norway spruces we find an even greater diversity of mycorrhizal fungi, including prized and sought-after species:

Boletus edulis (Porcini): the king of mushrooms is present in decent quantities, especially in mature spruce forests with bilberry undergrowth. Fruits from late summer to late autumn.

Cantharellus cibarius (Chanterelle or Girolle): one of the most appreciated edible mushrooms, characterized by its egg-yellow color and decurrent pseudo-gills. Abundant in not too dense spruce forests.

Russula spp.: a very well-represented genus with numerous species, including Russula vesca (edible), Russula cyanoxantha (edible) and Russula emetica (poisonous). Specific determination requires attention.

Mycorrhizal fungi of swiss pine

Swiss pine, present especially at higher elevations, hosts specialized fungi like:

Suillus plorans: characteristic fungus of Swiss pine forests, with a brown-olive cap and stem rich in brown dots. Edible after removing the sticky cuticle of the cap.

Cortinarius spp.: a very large and complex genus, with numerous species associated with Swiss pine. Many are difficult to identify and some are poisonous.

Saprophytic fungi: the decomposers of the forest

Saprophytic fungi play a fundamental ecological role in the Ceresole Reale Forest, decomposing dead organic matter and returning to the soil the nutrients necessary for plant growth. The large amount of dead wood present in the forest, especially thanks to the conservation policy of the National Park, favors the development of a rich community of lignicolous fungi.

Lignicolous fungi on conifer wood

The trunks and stumps of larch and Norway spruce host numerous species of decomposer fungi, including:

Fomitopsis pinicola (Red-belted Conk): one of the most common polypores on dead conifers. Forms large perennial shelves with a rounded margin of orange-red color.

Ganoderma applanatum (Artist's Conk): perennial polypore of large size that causes white rot of wood. The pore surface darkens to the touch, a characteristic used to "draw" on the fungus.

Pholiota spp.: genus of gilled mushrooms that grow in clusters on dead trunks. Several species present, some edible after cooking but difficult to identify.

Humicolous and terricolous fungi

Besides lignicolous ones, there are numerous saprophytic fungi that grow on the humus and plant remains in the undergrowth:

Macrolepiota procera (Parasol Mushroom): large umbrella-shaped mushroom very appreciated in cooking. Common in clearings and at forest edges in summer-autumn.

Coprinus comatus (Shaggy Ink Cap): characteristic mushroom that self-digests producing a blackish liquid. Edible when young, to be consumed quickly after picking.

Lepista nuda (Wood Blewit): mushroom of bright violet color that grows in rings in spruce forests. Excellent edible after cooking, but to be consumed in moderation.

Parasitic fungi and forest pathogens

Some fungal species of the Ceresole Reale Forest play a role as parasites or pathogens, attacking living trees and contributing to the natural forest turnover. Among these:

Heterobasidion annosum: dangerous root pathogen that attacks especially conifers, causing wood rot and predisposing trees to windthrow.

Armillaria spp. (Honey Fungus): fungi that can behave both as saprophytes and parasites. They attack weakened trees causing root rot. The fruiting bodies are edible after prolonged cooking.

Phellinus pini: parasitic polypore that causes red rot of pine and larch wood. Forms hard, woody fruiting bodies that persist for years on trunks.

Seasonality and phenology of fungal fruiting

Spring: the first appearances

As soon as the snow cover retreats (usually between April and May, depending on altitude), the first spring mushrooms appear. In the lower areas of the forest, especially under beeches and silver firs, it is possible to find:

Morchella spp. (Morels): among the most sought-after and prized mushrooms, they appear just after the thaw. Warning: must be consumed only after adequate cooking as they are toxic raw.

Calocybe gambosa (St. George's Mushroom): the spring mushroom par excellence, with a characteristic farinaceous odor. Grows in rings in grassy clearings, often associated with wild plums.

Gyromitra esculenta (False Morel): mushroom toxic when raw that can be confused with morels. Present in the same stations as morels, from which it is distinguished by the brain-like form of the cap.

Summer: the slow resumption

The summer months (June-August) see a relative pause in fungal fruiting, especially in dry years. However, after summer thunderstorms, it is possible to find:

Boletus edulis (Summer Porcini): appears sporadically after summer rains, especially in mature spruce forests.

Cantharellus cibarius (Chanterelle): begins to fruit consistently starting from July, especially in areas with bilberry undergrowth.

Autumn: the triumph of mushrooms

Autumn (September-November) represents the period of maximum fruiting for most fungal species. The ideal conditions of temperature and humidity favor the appearance of very many species, including:

Boletus edulis and other porcini (B. aereus, B. aestivalis, B. pinophilus): Reach their peak fruiting, especially after the first autumn mists.

Cortinarius spp.: the most represented genus in autumn, with dozens of different species. Attention to the dangerous Cortinarius orellanus, deadly.

Tricholoma spp.: include excellent species like T. portentosum and T. terreum, but also the toxic T. pardinum.

Winter: mushrooms in the silence of the snow

Even in the winter season, when the forest is covered in snow, some mushrooms continue to fruit, especially in the lower, sheltered areas:

Flammulina velutipes (Velvet Shank): grows in clusters on broadleaf trunks even during the coldest periods. Excellent edible.

Pleurotus ostreatus (Oyster Mushroom): lignicolous fungus that resists cold well. Appears on beech and poplar trunks even in winter.

Conservation and sustainable harvesting in the Ceresole Reale forest

Regulations on mushroom harvesting in the national park

In the Gran Paradiso National Park, mushroom harvesting is permitted upon issuance of a specific permit, which can be daily or seasonal. There are quantitative limitations (maximum 2 kg per person per day) and damaging harvesting tools like rakes or hooks are prohibited. Some areas of the forest may be subject to temporary or permanent bans for conservation reasons.

It is important to remember that harvesting is prohibited for rare or protected species, listed in specific lists. Among these, in the Ceresole Reale Forest, all species of the genus Hericium (cascade fungi), fungi of the genus Morchella (morels) in some areas, and several species of particularly valuable porcini are especially protected.

Sustainable harvesting techniques

To minimize the impact of harvesting on the fungal ecosystem, it is important to follow some simple rules:

Harvest only mature specimens, leaving those too young or old to ensure spore dispersal.

Use a knife to cut the mushroom at the base, without pulling it to avoid damaging the underground mycelium.

Place mushrooms in an aerated container (like a wicker basket) to favor spore dispersal during transport.

Do not destroy inedible or poisonous mushrooms, as they perform important ecological functions.

Monitoring and scientific research

The Ceresole Reale forest is the subject of numerous scientific studies aimed at monitoring the health status of the fungal ecosystem. Researchers from the Park, in collaboration with universities and research centers, regularly conduct:

Mycological transects: predetermined paths where the presence and abundance of different fungal species are monitored over time.

Diversity surveys: periodic sampling to assess species richness and the composition of the mycocenosis.

Studies on fungus-plant relationships: specific research on mycorrhizal symbioses and their role in forest health.

Curiosities and records of the Ceresole Reale forest

The giants of the forest: monumental trees

Among the centuries-old larches of the forest, some specimens reach exceptional sizes. The most famous is the "Larch of San Grato", which with its 35 meters in height, 7.5 meters in circumference and estimated age of over 500 years, is considered one of the oldest trees in Piedmont. This giant hosts a particular fungal community, with species specialized in colonizing ancient trees.

Rare mushrooms and exceptional findings

Presences of great scientific interest have been documented in the forest, including:

Hericium alpestre: very rare cascade fungus that grows on ancient silver firs. Considered a flagship species for the conservation of mature forests.

Boletus regius: Royal Bolete, of pink-purple color, found sporadically in the warmer areas of the forest.

Elaphomyces granulatus (Deer Truffle): hypogeous fungus that lives in symbiosis with conifers and constitutes an important food source for wildlife.

The forest in history and local culture

The Ceresole Reale Forest has a long history of use by humans. In the past, larch timber was used for the construction of roofs and facades of the typical Walser houses of the area. Mushrooms, especially porcini and chanterelles, have always represented an important food supplement for local communities, as documented in the historical archives of the municipality of Ceresole Reale.

Ceresole Reale forest: a heritage to preserve

The exploration of this natural sanctuary has revealed a world of complexity and interdependencies, where every element - from the majestic centuries-old larch to the humblest saprophytic fungus - contributes to the balance of the entire ecosystem. The extraordinary fungal biodiversity documented in these pages, with over 500 species recorded, represents not only a naturalistic treasure but also an indicator of forest health and the ecological stability of this Alpine environment.

The mycorrhizal symbioses, decomposition processes, and trophic relationships involving the fungal kingdom demonstrate how life in the forest is an integrated and mutually dependent system, where the disappearance of a single element can trigger chain consequences that are hard to predict. The Ceresole Reale Forest thus teaches us the importance of a holistic conservative approach, which considers habitat protection not as a simple sum of prohibitions, but as an articulated strategy to keep these precious ecological networks intact.

It is up to us, enthusiasts, researchers, and simple visitors, the task of passing on this heritage, respecting regulations, participating in monitoring programs, and spreading a culture of sustainable and conscious harvesting. Only in this way can we guarantee that future generations can continue to marvel at the majesty of a porcini emerging from the litter or the elegance of a rare morel, in a forest where the harmony between man and nature finds its most complete expression.