Thirty percent of beech trees killed by leaf disease

A new study has revealed that beech leaf disease (BLD) is causing serious damage to American beech trees in northeastern Ohio. Researchers from The Holden Arboretum found that around 30% of beech trees have died since the disease first appeared in 2014. This disease is expected to change eastern North American forests in the long term. The study, published in the journal Trees, Forests and People, tracked 263 beech trees over several years. They noted a rapid increase in tree deaths, especially among young saplings. In 2022 alone, mortality rates for saplings reached 14%. The disease is caused by a non-native nematode, which leads to dark and distorted leaves. These symptoms reduce a tree's ability to photosynthesize by as much as 60%. BLD has spread across 15 U.S. states and into Ontario, Canada, since it was first noticed near Cleveland. Researchers also found that the growth of surviving trees has slowed after the arrival of BLD. High tree density in some areas seems to worsen the disease's effects. However, beech mortality was less in plots treated with limestone and phosphate, suggesting that soil chemistry may play a role. The data comes from long-term monitoring at a research site that was set up in 2009, allowing scientists to understand the disease's progression. The team urges continued observation as BLD continues to spread and interact with other forest diseases and climate change. They highlight the need to find solutions as the health of beech trees declines.