We are in the second-to-last month of the year, and the increasingly shorter days, made even more noticeable by the switch from summer to winter time and the arrival of autumn rains, make us long for a spot by the fireplace, perhaps with a pan full of chestnuts, their skins freshly scored by the tip of a knife and gathered that morning from the nearby mountains.
Let’s take a closer look at the tree that gives us the delicacies we call fruits, which, as we discover, are actually seeds. The Sweet chestnut (Castanea sativa), belonging to the Fagaceae family, is a large, long-lived deciduous tree (often living over 500 years). It has a majestic stature, reaching 30-35 meters in height under optimal conditions, with trunks 3-6 meters in diameter. The famous “Sweet chestnut of a Hundred Horses” on Etna far exceeds these heights. The trunk is usually straight and, when isolated, quickly branches into large limbs, giving the crown a broad, rounded shape. Its leaves are deciduous, simple, alternate, and spirally arranged, with an elliptical-lanceolate shape and serrated edges.
As a species that grows at least 200 meters above sea level and reaches up to 1,300 meters, it is characterized by both late foliage and late flowering, to avoid frost damage: the first leaves begin to emerge in late April, and the flowers wait until late June to appear. The species is monoecious, with catkin inflorescences that are either mixed or all-male, while the tiny floral casing of the female flowers eventually transforms into the familiar burr. Pollination is primarily anemophilous, but the presence of nectaries derived from the pistil buds and the scent of the male inflorescences attract frequent visits from bees, beetles, and flies. Pollination does not depend on insects, as the female flowers lack attractants and contact with insects is random.
The chestnut burr, as we have already seen, is very prickly and usually contains three fruits, though sometimes there are two or as many as seven. These fruits are achenes with a smooth, leathery, brown pericarp (the “shell” of chestnuts). What we eat is the seed, which consists of two cotyledons with hard, ivory-coloured flesh, protected by a light brown membrane.
Chestnut wood is especially resistant to woodworms due to its high tannin content. Despite its high demand, in the past, inhabitants of small mountain villages found it difficult to cut down chestnut trees to make furniture: when snow isolated them for days at a time, chestnuts served as an incomparable source of energy.
Many animals use chestnuts to prepare for winter: wild boars, badgers, and deer use them to build up subcutaneous fat that will serve as their energy reserve; squirrels store them in their larders, and dormice use them to prepare for hibernation.
But it’s not just chestnuts that provide winter energy for forest dwellers: let’s not forget acorns! In addition to mammals large and small, acorns are also appreciated by jays and woodpeckers. Furthermore, while chestnuts are found only in ecosystems defined by precise parameters (altitude, sunlight, temperature, etc.), acorns are found almost everywhere, as oaks grow nearly everywhere. Of course, the term oak is quite generic, given that the planet is home to approximately 600 species! In Italy, the most common are about nine species, each living in specific ecosystems. Let’s look at the three most common. Starting from the coastal areas of the Mediterranean, we find the Evergreen oak (Quercus ilex) of the Fagaceae family. Its preferred habitats are dry woodlands and Mediterranean scrub; it is therefore an evergreen species. It is a very long-lived plant, often reaching 1,000 years of age. Reaching up to 25 m in height, its trunk can exceed a metre in diameter; its dense, globular crown is dark green, formed by large branches that branch out quickly from the trunk.
The leaves are leathery and persistent, lasting an average of 2 to 3 years. The plant is highly heterophyllous, so the leaf blade can vary in size and shape on the same plant: from elliptical to lanceolate or rounded, ranging in length from 3 to 7 cm and width from 1 to 3.5 cm, with a cuneate or rounded base. The margin can be entire or coarsely toothed and can even be spiny on the lower parts of the plant; this is its way of protecting itself from grazing.
The holm oak blooms from April to June, sometimes blooming again in autumn. The male flowers are grouped in pendulous catkins, which facilitate wind pollination of the tiny female flowers.
It is important to note that the holm oak’s root system is taproot-like, although it develops strong lateral roots that produce suckers. The taproot can penetrate several meters deep, even into rocky terrain, making the species highly resistant to arid environments and adverse weather conditions. This characteristic makes it valuable in areas prone to landslides and is an important reason to prevent the slopes where this species grows from being burned.
The oak tree that isn’t afraid of fire is the cork oak (Quercus suber). This species’ most distinctive feature is its bark. Initially smooth and gray, it quickly thickens and becomes wrinkled, furrowed with deep grooves, light in color on the outside and pinkish on the inside, where it becomes spongy. In a few years, it can reach a thickness of 5-7 cm, which persists throughout the tree’s life: “the cork.” It is the cork that protects it from fire. Thus, only the leaves burn, which will sprout again the following spring. Like the holm oak, the cork oak is evergreen, but significantly smaller; the trunk is seldom straight and soon divides into irregular branches, forming an asymmetrical crown that is broad and less dense than that of the holm oak. Here too, the leaves vary depending on the age and height from the ground. The acorns of the cork oak are easily distinguishable because the apical scales of the cup are free and a little “curled,” so much so that a little girl, during an outdoor workshop, said that those acorns had perms like her mother!
While evergreen oak and cork oak prefer drier, warmer areas, this is not the case for the large common oak (Quercus robur), a component of the extensive, typically continental lowland forests of central and eastern Europe. This species endures harsh winters and warm, but never dry, summers with year-round water availability, even tolerating prolonged flooding during dormancy.
Unfortunately, this species primarily occupied the most fertile areas of the country, most of which have been altered by humans for cultivation. Its decline continues, with a high risk of extinction in many parts of peninsular Italy, where it comes into contact with holm oak forests below and beech, chestnut, and Neapolitan alder forests above.
The common oak is a large deciduous tree of primary ecological importance, reaching heights of up to 50 meters with trunk diameters exceeding two meters. It is also a very long-lived species, sometimes living for more than 500 years. Its robust trunk branches into large, broad limbs, forming a wide but not very dense crown, supported at the base by large, horizontally arranged branches.
The flowers appear along with the leaves from late April to May and, as in other oaks, consist of catkins of male flowers and small female flowers that, after wind pollination, develop into acorns, which ripen in September-October. Common oak acorns are 2 to 3.5 cm long and have a dome covering 1/4 to 1/3 of their length, formed by overlapping triangular scales, larger near the petiole.
We’ve observed that chestnuts and acorns are mainly eaten by mammals, but this is not the case with the fruits of the mastic tree (Pistacia lentiscus), a member of the Anacardiaceae family, whose drupes are highly favored by birds. I am lucky to have an exceptionally large mastic tree at the edge of my garden, which produces abundant fruit. When large flocks of starlings land on its branches with a noisy din, absolutely nothing remains after their feast!
An evergreen shrubby plant, rarely a tree, with a strong resinous odor, the mastic tree typically has a dense, bushy, globular crown. Being a heliophilous, thermophilous, and xerophilous species, it tends to develop the typical pulvinus shape, which helps protect the soil it grows on from drying out. A common component of the evergreen Mediterranean scrub, the mastic tree grows from sea level up to 600 meters, often alongside wild olive, phillyrea, and myrtle. It is not a colonizing species but can become dominant during periods of scrub degradation, especially after repeated fires, due to its ability to regrow easily from the roots. The alternate, paripinnate, and glabrous leaves are dark green, with 6-10 obtuse, elliptical-lanceolate segments with entire margins and an obtuse apex, up to 30 mm long. The particularly tough lamina helps prevent dehydration. The small unisexual flowers, arranged in panicles, are mainly wind-pollinated, although bees that visit them to collect pollen may also assist in pollination. The small, globose drupes, 4-5 mm in diameter, are fleshy, initially reddish, then black when mature, and contain one seed.
The mastic tree is of considerable ecological importance because it quickly restores a good level of vegetation cover to bare soil. It is regarded as a soil improver. The soil beneath its bushes is considered an excellent gardening substrate. Due to its hardiness, it is one of the most suitable plants for environmental restoration and landscaping of marginal or challenging areas, such as steep slopes and rocky terrain.
Finally, I would like to mention two other very important species typical of the Mediterranean scrub, which this month provide fruits that are very popular with mammals (including us) and birds: the strawberry tree (Arbutus unedo) of the Ericaceae family and the common myrtle (Myrtus communis) of the Myrtaceae family.
But we won’t discuss the delicious jams you can make with the red strawberry tree berries or the many uses for the berries and fragrant common myrtle leaves. Nor will I mention how much robins, black redstarts, blackbirds, blackcaps, jays, and magpies enjoy the freshly ripe strawberry tree berries. Or how irresistible myrtle berries are, especially for thrushes. I won’t do that because Beatrice Lupi has already covered these topics in two of her very interesting articles, which I will refer you to. See you in December.
The Strawberry Tree and its Nymph
Summer has come, the myrtle is in bloom
Credits
Author: Anna Lacci is a science communicator and expert in environmental education, sustainability, and place-based teaching. She is the author of documentaries, nature books, workbooks, interdisciplinary teaching resources, and multimedia informational materials.
Translated by Maria Antonietta Sessa
