The Plane trees around Barga under threat
The Plane trees in and around Barga are under threat from a fungus which has already killed most of the plane trees in Forte dei Marmi before moving onto and decimating many of the famous trees on the walls of Lucca during the 80’s and early 90’s. Since then the canker stain fungus has gradually moved up the valley and is now “knocking on the door of Barga”
This morning on the road to Gallicano, tree surgeons were already cutting down and removing many of the plane trees lining the road.
A disturbing number of trees have been marked with a large green M for Morto – already lined up for the chop.
It is probably only a question of time before the fungus makes it way up the mountainside to Barga.
The cause of canker stain of plane trees is the fungus Ceratocystis fimbriata Ell. et Halsted, f.sp. platani Walter (=Cfp) (Ascomycotina, Ophiostomatales)
So how does the fungus do its dirty work ? Even a very small wound is enough to allow the mycelium to invade the plant tissue and start the infective process.The parasite can invade the tree at various levels: on the main or secondary branches subject to frequent pruning; on the trunk, always exposed to wounds from various causes, especially near ground-level; and on roots that emerge above-ground, as occurs with trees growing in compacted and anaerobic soils that are frequently encountered in street and city plantings.
In the 1940’s canker stain ravaged urban plantings of plane trees in the larger American cities along the Atlantic coast. During the second World War wood from infected trees was used to package materials for the war effort, and this is probably how the pathogen was introduced to the European continent, giving rise to the processes of infection here.
This supposition is borne out by the fact that the first centres of infection in Europe were in or near the major port cities: Naples, Livorno, Syracuse, Marseilles and Barcelona, which were very active during and after the second World War. It is likely that at first only one of these ports became ‘infected’ with the parasite from overseas, and that from this single point it spread out to other Mediterranean port cities.
The first epicentre of the disease in Italy is thought to have been the Naples-Caserta area (Cristinzio et al., 1973); this hypothesis is confirmed by the fact that, when the disease was detected for the first time at Forte dei Marmi in Tuscany, it had already killed many of the 200 year-old planes lining the Vialone Carlo III, the broad avenue that leads to the Palace of Caserta.
Canker stain did not assume an epidemic pattern until several years later, but then it spread in a dramatic manner through Italian cities, as it had done in North America before. A survey from Forte dei Marmi revealed that in the 20 year period 1972-1991, 90% of all planes there became infected and died. Subsequently the disease spread out from Forte dei Marmi to much of Versilia and to many towns of Tuscany: Massa Carrara, Lucca, Pisa, Livorno and Florence. – source; Journal of Plant Pathology (1999)