The number of non-native plant species capable of reproducing spontaneously outside their native range has increased significantly over the last centuries. Some of these species spread invasively, causing ecological and/or socio-economic damage, and in Switzerland their cultivation or trade can be banned or regulated under the Ordinance on Deliberate Release into the Environment.
Since 2024, the windmill palm (Trachycarpus fortunei) has also been included on this list, a species that has become iconic in the Ticino landscape and a tourist attraction. For such iconic species, a ban without a plausible alternative is unlikely to gain public support, and its effectiveness remains limited. Being able to propose non-invasive plant species with equivalent ornamental value would represent a proactive and effective measure for the gradual replacement of the windmill palm.
This project aims to develop a methodological approach to assess the invasive potential of candidate species, their adaptability to the local climate, and their resistance to specific pests. In this specific case, the goal is to identify other palm species that are non-invasive and less susceptible to the Paysandisia archon, which could replace the windmill palm in the Ticino landscape.
Collaborators
Dr. Vincent Fehr, vincent.fehr(at)wsl.ch¹
Dr. Gianni Boris Pezzatti, boris.pezzatti(at)wsl.ch¹
Dr. Alessio Maccagni, alessio.maccagni(at)ti.ch²
Project Duration
2025 – 2026
Project Status
Ongoing
Financial Support
Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Repubblica e Cantone Ticino (Isole di Brissago), Federal Office for the Environment (FOEN), Ronco sopra Ascona
¹ Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Insubric Ecosystems Research Group, Cadenazzo
² Repubblica e Cantone Ticino, Giardino botanico cantonale delle Isole di Brissago, Isole di Brissago