Trees suffer from heat stress and are already turning brown

Summer is still in full swing, but some trees in our province are already taking on autumn shades. In many cases this is a direct result of the dry summer. Tree manager André Efftink does not immediately get stressed, but does not hope that the Netherlands will have to make do with a summer like this next year.

Beech trees, among other things, are affected by the drought, says Efftink. Diagonally across from his house in Zweeloo, he points to two lime trees. One of the two trees is slowly starting to look brown, while the other is still nice and green. “That’s because the rear tree has more room to grow. It then has less trouble with the drought.”

After three years of drought, 2021 was a good summer for trees and shrubs, says Efftink. “But it is not a year like this. Summers like this are becoming more common and then you see that the condition of trees is deteriorating. You can especially see that with the beech trees. They really get a hit again and as a tree manager I am there not happy about it.”

It is not yet cause for great panic, he believes. “The layman will not notice much of the dry summer in the autumn and winter. There are already trees that are preparing for that period. Depending on the temperatures in the autumn, the leaves remain on the trees for a long or short time.”

More dangerous are the spontaneous ‘branch breaks’ that can occur as a result of heat stress. Yesterday it was hit in Zuidlaren, where a tree broke off on the Groningerstraat. “We heard a big noise and ticking at 10.20 pm, as if fireworks were going off,” says Lieuwe Melchers.

When Melchers came out, his tree was found to be split in two. “I was up to my ankles in the branches.”

Spontaneous branch breakage happens very rarely and is difficult to explain, says Efftink. “We have three thousand trees under management, but only one broke down, so that was in Zuidlaren.”

He blames the break on heat stress. “A tree that does not receive moisture for a long period of time will have a very dry core. If water does fall, it causes stress. Apparently something happens that causes it to finish its branch.”

Nature lovers need not be afraid, according to Efftink. “It almost never happens and when it does, it’s often not in the forest. You don’t have to avoid nature for it.”

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