Clingy leaves

“On my daily walks I see trees that have not lost their leaves. How can this be explained? “, Ask yourself this year, probably many ramblers and walkers. What’s wrong with our bushes and trees?

The autumn 2005 has compensated for the rainy summer: the days were pleasant temperatures and high nighttime temperatures rarely really deep. This has got to feel the plant world: the late Flora has been preparing for the winter. Deciduous plants (fruit trees, shrubs, forest trees, etc.) must form in the autumn of a separation layer in the Anwachsstelle of the leaf,


so they get rid of their leaves. Many of the crops (cherries, plums and other tree and shrub species) start early with the formation of the separation layer. Other wood species make this separation layer late as apple, quince, pears and chestnut trees. The formation of the isolating layer depends on the autumn weather conditions and temperature variation.

The warm autumn of 2005 led to the separation layer formation began late. Husistein Alfred, director of the experimental farm orchard at Agroscope Changins-Wädenswil (ACW), knows what happened next: “The prominent cold snap around the 20th November 2005 (-10 degrees and lower) for those plants came too early, which was the separation layer is not yet ready formed. The leaves froze and could not be solved by the Anwachsstelle. Many of these leaves fall during the winter months by snow and wind, others are repelled when new growth. ”

As the frozen leaves little or no water to evaporate, it will not affect the plants. Should Erfrierungsschäden show next spring, which is not expected for most shrubs, they are already around 20 November happened. Thus, this rare phenomenon is merely a freak of nature. It occurs in our area about every 5 to 10 years at a time. In regions where the hair dryer determines the autumn weather (Graubünden, Chur Rhine valley), the phenomenon even more common.