The super resistant palm that has invaded Northern Italy

A fragment of beach in front of the glaciers. In good weather, walking in the woods in the Alps, you might come across several palm trees. They are not very tall and form small islands of tropical scrub within the forest. These plants, in reality, are not entirely out of place. On the contrary: originating from a vast area that stretches from central China and Japan to the slopes of the Himalayas in Southeast Asia, they can withstand winter temperatures that are only rarely reached today in our mountains. There Fortune palm (Trachycarpus fortunei), as this species is called, was (and partly still is) a classic of exotic gardens in colder climates. In its natural environment it can grow above two thousand meters in altitude. In Europe it was introduced at the end of the nineteenth century for its adaptability to the climate of northern Italy where it can be grown outdoors, and without incessant care, even in alpine areas.

Until ten years ago it was a ghost and remained confined to domestic gardens but with the increase in temperatures it escaped and began to colonize the nearest natural areas. Since last year in Switzerland, where it is so common that it is called the Ticino palm, it has become an ecological emergency while in Italy it is spreading, for the moment, at a slower pace.

The Fortune palm has been included in the list of species of Atlas Flora Alpina, an international cooperation project launched in 2022 to document the entire Alpine vegetation in which research centers and institutions from Austria, France, Germany, Italy, Slovenia collaborate and Switzerland. In the last census, carried out in 2004, this plant was not yet registered.

“The palm is now reported in many thermophilic forests, where there are milder temperatures, along the entire southern band of the Alps from Piedmont to Friuli-Venezia-Giulia. – explains Alessio Bertollibotanist and deputy director of the Rovereto Civic Museum Foundation, Italian partner of Atlas Flora Alpina – The plant has been present in gardens for more than a century and has always had an invasive character but until the first half of the 2000s it had not naturalized thanks to natural selection practiced by the harshest winters. The recent explosion of this species is most likely due to a warmer climate“.

Even if they exist in Switzerland specimens that resist snow and prolonged frost thus risking replacing the native flora. “We are not at this stage yet but for sure the Fortune palm is occupying an important ecological niche in the undergrowth where important species grow spontaneously like the dogwood or the philadelphus. – continues Bertolli – Compared to these plants, the palm does not lose its leaves in autumn and continues photosynthesis, thus continuing to grow, saturating the environment”. evergreen alien plants favored by the greenhouse effect has a precise name: it is called laurophilization. The greatest damage is suffered by i deciduous broad-leaved forests such as the oak forests of oak and oak or the communities of black hornbeam and manna ash.

Despite the bad reputation, several examples in 2017 Trachycarpus fortunei they were planted in the flowerbeds of Piazza Duomo in Milan for a project restyling of green areas. An original choice but which had raised more than one doubt among the experts. In reality the palm, included in the black list of invasive plants in both Lombardy and Piedmont, can be purchased in a nursery without many problems. “Often the spread of these non-natives also starts from rotation work in the garden. – continues the botanist – The Fortune palm, like the Japanese knotweed and others of this category, has extraordinary reproductive capabilities and colonizes all available space until the owner decides to get rid of them, contributing, involuntarily, to their propagation“.

A similar case, in which the biological invasion is due to human error, is that ofailanthus, a tree pest and bête noire for any green area. In the 19th century it was imported from Asia to offer an alternative to the leaves of white mulberryattacked by an epidemic, for the feeding of the precious ones silkworms. Too bad that the substitute offered to the insects was not to their liking. Once the trees were eliminated, the species, which can clone itself from cuttings, nevertheless spread at an unstoppable pace.

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