Bhubaneswar: Trees that grow close together can prevent damages caused by powerful storms by supporting each other.

An Assistant Professor of of Shinshu University in Japan, Kana Kamimura, and her colleagues monitored two different plots of Japanese cedar trees, one of which had been thinned to assess whether giving individual trees more room to grow made them more vulnerable to wind damage, when typhoon Trami unexpectedly hit in early September 2018.

“I set the plot in 2017 and the typhoon came in 2018, and half of my plot was destroyed,” says Kamimura.

The team measured the stress forces experienced by the trees before, during and after the typhoon and surveyed the resulting damage. The plot that hadn’t been thinned kept all of its trees, while the sparser plot lost many.

The researchers think that the tight spacing helped protect the trees in the plot that wasn’t thinned by dissipating the force from the wind through collisions between branches of neighbouring trees. This stopped the force travelling into the sensitive stem and roots below, where it might help uproot trees.

They also found that the trees that did fall in the thinned plot didn’t fail instantly but over time, like a piece of metal that’s repeatedly been bent back and forth before finally breaking. Understanding how far apart to space trees in plantations could be important for the timber industry, and for efforts to plant forests for carbon offsetting.

It is important to conduct more experiments with different amounts of thinning. If we can find a method for how many trees we should remove, it will be very helpful for foresters managing forests,” says Kamimura.