Study finds trees that grow close together stand a better chance against storms

The findings could provide insight into better forest planning.

Trees are more able to withstand wind damage when they grow close together, according to a new study by a team of researchers at Shinshu University in Japan.

The team was monitoring Japanese cedar trees in two different plots of land: one that was thinned so that there was a greater distance between trees and a control plot that was left untouched, when typhoon Trami unexpectedly hit in September 2018 as a Category-5 storm, bringing peak wind gusts that topped 180 kilometres per hour.

Post-storm analysis revealed the thinned-out plot sustained more damage, with several trees downed. The trees that did not topple leaned over, the study authors say, and did not return to their original upright positions.

Meanwhile, the control plot remained intact, with all trees standing.

"All trees in both plots should have received similar pressure from wind turbulence at the same time," the authors write in a statement.

"Why did some trees survive and not others?"

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Scientists reviewed the stress forces the trees underwent before, during, and after the storm via sensors installed at the start of the study.

It's believed the tight spacing of the trees in the control group caused the branches of neighbouring trees to crash together when the wind hit, dissipating its force, NewScientist says. This prevented the force from reaching the stems and the roots, which can lead to uprooting.

Researchers say the findings can provide insight into better forest planning for the timber industry and organizations that plant trees for carbon offsetting purposes.

"Further research of diverse forest settings would bring more clues as to how forests have survived millennia and what people can do for forests under changing climates," the authors write.

Thumbnail: Custom graphic of cedar branches by Cheryl Santa Maria. Cedar image courtesy: Canva.