A chance discovery in a mixed forest in Switzerland reveals that tree-to-tree interaction in forests goes beyond mere competition for resources.
Forest trees are even more interconnected than thought, suggests a new study, which showed that around 40 per cent of the carbon in fine roots of spruce trees came from neighbouring trees. This level of sharing can be crucial for forests, especially under stress conditions like wildfires, say the authors in their paper published in Science recently.
Human-driven activities have been releasing vast amounts of CO2 into the atmosphere since industrialisation began two hundred years ago. Consequently, there is a lot of interest in understanding to what degree forests the largest terrestrial pool of biological carbon, are able to absorb this amount, thereby mitigating climate change, said Tamir Klein who studies eco-physiology at University of Basil, Switzerland.
While investigating the responses of trees to elevated CO2, Klein and team stumbled upon this discovery. To track the flow of carbon, they had used a tall canopy crane to label five 40-metre-tall Norway spruce trees with stable carbon isotope 13. Five unlabelled spruce trees were used as control. The labelled and unlabelled trees were then measured for C-13 from “tip to toe” – canopy twigs, stems, and fine roots. This was also done for neighbouring unlabelled non-spruce trees. Their methodology ensured no label transfer to other trees. However, the team noticed something unexpected. “We discovered that labelled carbon does find its way to other trees, albeit in the root zone,” said Klein.