Goodbye maples, pines

By Akanksha Gulia

Climate change may cause some tree species to disappear

Imagine a hill station without pines. Worse, Canada sans the maple tree. This could become a reality. Scientists at the Hebrew University of Jerusalem in Israel claim many tree species that depend on the wind to disperse their seeds, like pines and maples, might become extinct due to changes in climate like higher concentrations of CO2 in the air and reduction of surface wind speed.

Previous scientific research suggests that further increase in CO2 concentrations will cause trees to produce more seeds and reach maturity earlier. But the weakening of wind speed would reduce the spread of these seeds. It is not known whether a balance between these forces would be sufficient to counter the effects of climate change. It is also unclear whether an increase in wind speed, together with higher seed production and earlier maturation will result in faster spread of trees.

The study focuses on the spread of North American wind-dispersed trees, says lead researcher Ran Nathan. The results show that trees would be unable to spread at a pace that will cope with the expected rise in temperature. This theory has been based on a newly developed mechanistic model that predicts trends in plant spread.

“A 3°C increase in global mean temperature will make conditions unfavourable for pines unless they move to higher altitudes. The rate of change in temperature per decade is faster than the trees’ ability to adapt,” explained J Srinivasan, chairperson of the Divecha Centre for Climate Change, Indian Institute of Science, Bengaluru.

The effect of climate change on trees is not limited to a particular area or a particular species, says Pankaj Agarwal, director of the Institute of Wood Science and Technology in Bengaluru. He adds: “The study’s result may apply to tropics, and species that are dispersed by agents like animals and water.”