Unusual Leaf Fall Signals Environmental Changes

WROCŁAW, Poland — This year, trees in Poland are shedding their leaves earlier than usual, with many starting to lose their foliage in late August and early September. This shift raises concerns about potential environmental changes, according to experts.

Professor Przemysław Bąbelewski from the University of Wrocław attributes this phenomenon to climate change. Traditionally, leaf drop was a hallmark of October autumn, but the recent timing suggests a troubling trend.

“I observe this mainly in native species like birches, hornbeams, and linden trees in Lower Silesia,” Bąbelewski said. “The average air temperature is rising, and there is a lack of snow in winter. Consequently, spring soil lacks stored water.”

As water becomes scarcer, trees activate a defense mechanism, producing ethylene and abscisic acid. These substances initiate the aging process of leaves, leading to their eventual fall.

In contrast, coniferous trees such as pines and spruces can retain water more effectively due to their waxy coatings and smaller surface areas. This allows them to survive harsher conditions.

Bąbelewski also emphasizes the ecological importance of fallen leaves, which are essential for biodiversity. “Autumn leaves play a critical role as mulch, providing habitat for soil organisms like earthworms and various insects,” he explained. “They contribute to the formation of fungi and bacteria that create humus, a crucial soil component for plant nutrition.”

Additionally, fallen leaves protect roots and seeds from frost while preventing excessive water evaporation from the soil. However, Bąbelewski warns that white horse chestnut leaves should be removed to combat the invasive horse chestnut leaf miner, a harmful pest.