TREES OF LIFE
New research may change the way we view forest ecosystems.
Growing over 50m tall and living for more than 2,000 years, kauris are one of the most ancient tree species in the world. Found in the northern districts of the North Island, kauris are thought to have existed for around 20 million years. But we are still learning about these amazing trees, and only recently two scientists from Auckland University of Technology (AUT) made a discovery that may shift the perception of trees as individuals towards understanding forest ecosystems as ‘superorganisms’.
On a hike, AUT associate professor Sebastian Leuzinger and senior lecturer Martin Bader found that a seemingly dead kauri tree trunk was actually still alive. Examining further, the scientists discovered the kauri stump was keeping itself alive by holding onto the roots of neighbouring kauri trees; exchanging water and resources through a grafted root system. Leuzinger says, “For the stump, the advantages are obvious – it would be dead without the grafts, [as] it doesn’t have any green tissue of its own. But why would the green trees keep their ‘grandpa’ tree alive on the forest floor while it doesn’t seem to provide anything for its host trees?”
One explanation is that we need to look at forests as superorganisms, where the trees all help each other to improve their collective stability. Leuzinger says, “During a drought, for example, trees with less access to water might be connected to those with more access … allowing them to share the water and increase their chances of survival.”
A ‘superorganism’ by definition is a group of interacting organisms of the same species that functions as an organic whole. The concept usually relates to insect colonies like ants and bees – but this new research suggests that forests might be included as well.