Beech groves may completely disappear from the face of North America in the coming years due to the spread of a mysterious disease that kills the youngest trees in 2-3 years. The results of observations of its distribution were presented in the journal Forest Pathology.
The so-called invasive species of animals that penetrate new territories and continents thanks to unconscious "help" from humans have recently become one of the main problems for the ecology of the entire planet.
For example, the entry of Brazilian fire ants into the United States about 70 years ago caused an ecological disaster. They quickly destroyed several species of snails and markedly reduced the number of other species of insects and even mammals.
These problems concern not only animals but also plants. Citrus plantings around the world are today mowed down by the East Asian bacteria Candidatus liberibacter, which spread across the Earth in the middle of the last century. The "invasion" of the Colorado potato beetle into the USSR and other countries of the socialist bloc in 1960 was a great tragedy for collective farms and households.
Two recent examples of such environmental tragedies are the almost complete destruction of some subspecies of elms, ash trees and poplars in the United States by "saboteurs" insects from the Russian and Chinese Far East, beetles and baby moths. The total damage from their invasion can amount to several hundred million dollars.
Bonello and his colleagues have added another tree species to the "environmental victims of world trade", uncovering a mysterious epidemic of suspected bacterial origin that has affected thousands of beeches in southern Canada and at least four states in the United States.
The first traces of it, according to the ecologist, were found in northeastern Ohio about six years ago. As the locals noticed then, the leaves of some beeches began to change in strange ways. Dark stripes began to appear on their surface, gradually filling the entire space between the veins.
When this process was completed, the leaves turned black and died, resulting in the death of the tree about three years after infection if it was young, and in the sixth year for the oldest and largest beeches.
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Initially, environmentalists believed that the beeches died not because of disease, but because of the poor environmental situation in this part of the state, and did not pay much attention to the disease. Only three years ago, according to Bonello, scientists began to seriously study the problem, noticing that oak trees began to die en masse in dozens of other parts of Ohio and in neighboring states.
Observing the spread of the disease over the past five years, environmentalists have found that it has managed to penetrate three neighboring states and the territory of Canada. In addition, scientists expect foci of infection to already exist in 30 other regions of the United States.
Despite the fact that this infection most strongly affects the American subspecies of beeches, it can also penetrate the leaves of European and Asian trees, as the observations of Bonello and his colleagues show. This means that it can spread throughout the Old World and acquire a global character in the coming years, scientists sound the alarm.
