Birch trees across Finland shedding leaves; cause unknown

Birch trees throughout Finland are exhibiting premature leaf loss, a widespread issue that has generated significant concern and numerous reports to the Natural Resources Institute (Luke). Observations indicate that trees along roadsides, in avenues, open areas, and small groves are particularly affected.

The precise reason for this phenomenon remains unclear. Luke's leading researcher, Tiina Ylioja, stated in a press release that the extensive nature of the problem suggests a combination of environmental stressors. These potential factors include drought, fluctuating temperatures, exposure to road salt, and soil compaction, especially in trees growing in exposed locations or urban environments.

"The exact cause of the leaf fall is not yet known. However, the widespread nature suggests that the background may be an environmental factor that has burdened the trees or the combined effect of several stress factors," Ylioja explained. She noted that in some trees, buds failed to open normally, leaves did not form, and some shoots from the previous year have also died.

While the situation is worrying, Ylioja emphasized that leaf loss does not automatically signify the tree's demise. If the root system is healthy and sufficient leaf mass was produced, the tree may recover and grow new shoots later in the growing season. Samples have been taken to identify fungal species on the branches, with more detailed results expected in the fall. Currently, there is no specific control method for this issue, and residents are advised to monitor the situation and report severely symptomatic trees.