Autumn leaves late to appear due to warm September, October

Because September and October have been very warm, the leaves fall from the trees very late. Leaf discoloration has also only just started, according to Arnold van Vliet and Wichertje Bron of Natuurkalender and Wageningen University. Compared to 60 years ago, autumn starts two to three weeks later, and it could be even later if it does not get colder and night frost doesn’t occur.

In the past, pedunculate oaks and beech trees would have been completely discolored by now, but they are still largely green. Trees like ash, lime, maple, and horse chestnuts would already be bare but still have their leaves. Leaf discoloration and leaf fall start when the days become shorter and the temperature drops. However, September and October this year were exceptionally warm, with an average temperature of 15.3 degrees Celsius. Only 2006 had an even warmer autumn, according to the scientists.

The KNMI also noted that autumn is getting warmer. Autumn will warm up the most of all seasons, according to the meteorological institute.

That means that autumn in nature will start later and later, according to Van Vliet and Bron. The question is also which native trees will survive if temperatures continue to rise. Oak trees, for example, are already dropping branches due to the drought in the summer months.