The chestnut tree is a heliophilous broad-leaved tree, meaning it thrives in sunlight. It is a relatively frugal plant but requires deep, slightly acidic soils that are rich in phosphorus and potassium. These can originate from sandstone, tuff, and granite. The species rarely extends beyond 1000m.
The chestnut tree is a very long-lived species (it can live up to 500 years) and can become imposing; on average, it reaches 15-20 meters in height, but some specimens can exceed 30 meters.
The stem is erect and branches at a short height; in the basal part, it can have a diameter of 2-3 meters. The crown is expanded, more or less roundish; in adult trees, it can reach a diameter of 20-25 meters.
In young plants, the bark is thin and smooth, with a reddish-brown or gray-olive color. With age, it becomes thick and develops grooves with a typical spiral pattern.
The leaves are intensely green on the upper side and lighter on the lower side. They are large (up to 20 cm in length and 6 cm in width), elliptical-lanceolate in shape, with serrated-toothed edges and an acuminated apex. The leaves appear late in spring, and for this reason, the chestnut grove looks bright until early summer.
The chestnut tree is a monoecious species, meaning it has unisexual flowers (male and female) arranged on the same plant. The species develops inflorescences called 'catkins' on the outermost part of the crown. These are very showy and have a penetrating smell. For good fruiting, the catkins must grow in conditions of illumination and sunshine.
Female flowers are collected in a green, scaly envelope that then forms the dome, or the hedgehog. Each female flower usually turns into a chestnut. There are usually three fruits inside the hedgehog, the lateral ones are hemispherical, while the central one is flattened. Flowering occurs between June and July.
Pollination is entomophilous (i.e., by insects) and partly anemophilous (i.e., by wind).
The chestnut tree is 'self-sterile' due to the temporal mismatch of male and female flower maturation. Pollination is therefore always crossed with other plants.
The chestnut is a dry fruit called achene and does not open when ripe. It is covered with a smooth, leathery skin of brown color (called pericarp); at the base, it has a light-colored scar (hilum), and at the top a characteristic tuft (torch). A thin membrane (episperm), more or less hairy, covers the seed, which is the edible part of the chestnut. The dome, or hedgehog, falls between September and October and opens into 2-4 valves.