Infectious Tree Diseases Among Major Causes of Tree Mortality In Forests, Urban Areas

(Photo : Getty Images/Michael Dantas)

Emerging diseases pose a serious threat to the world's tree population.

A recent study shows that these diseases have become substantial contributors to tree mortality in both forests and urban landscapes around the world.

Alarming Rates of Emerging Diseases

The study, which was just published in NeoBiota, examined over 900 new illness reports on 284 tree species from 88 nations and evaluated how emerging infectious diseases have accumulated geographically and on various hosts.

Dr. Andrew Gougherty, a research landscape ecologist at the USDA Forest Service, discovered that the number of new diseases has increased substantially during the last two decades.

"The accumulation is apparent both where tree species are native and where they are not native, and the number of new disease emergences globally were found to double every 11 years," he explains.

Pines had the most new diseases among the trees he examined, followed by oaks and eucalypts.

This is most likely due to their widespread native distribution in the Northern Hemisphere and the widespread cultivation of pine forests around the world.

Europe had the highest cumulative accumulation of new diseases, although North America and Asia were not far behind.

Furthermore, with the exception of Latin America and the Caribbean, he discovered more new tree diseases in places where tree species were native versus non-native, most likely because the majority of the trees he studied were not native to this region.

This outbreak emphasizes the critical need for extensive research and appropriate management techniques to protect tree populations from the looming threat of infectious diseases.

Finding New Hosts

Emerging infectious diseases are not only constantly being introduced, but they are also always looking for new hosts, posing a threat to a growing number of tree species.

According to the study, the risk of emerging illnesses is highlighted by their propensity to cause extraordinary amounts of mortality when they find novel hosts.

Unfortunately, there is minimal indication of saturation in emergent tree disease accumulation. Global trends show little sign of stopping, implying that the impact of newly discovered diseases will likely compound and imperil tree populations globally and in the future.

"Climate change is likely also playing a role, both by creating more favorable conditions for pathogens and by stressing host plants," Dr. Gougherty said.

Although not all illnesses kill their victims, some have a significant impact on host populations.

Chestnut blight, possibly the most well-known tree disease in North America, completely eradicated chestnut as an overstory tree in its natural area in the Appalachian Mountains in the twentieth century.

Recently, experts noted the sudden oak death in California, ash dieback in Europe, and butternut canker in the eastern United States, all of which have the potential to eradicate host tree populations and disrupt ecosystems.

Combating this growing threat will necessitate collaborative efforts from scientists, politicians, and the general public.

The health of our trees is a major concern not only for the environment but also for our economy, culture, and well-being.

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