A new study has revealed that trees are losing their leaves, or reaching senescence, early because of climate change. This is in contrast to the earlier assumption that suggested that as the planet keeps heating up, the growing season will last longer and the autumn season will come later.
The deciduous trees go through the process of senescence when the leaves turn yellow, orange or red, thus making an end to their absorption of carbon dioxide via photosynthesis and extracting nutrients for growth. Research has found that due to global warming, spring leaves are emerging in European trees about two weeks earlier, compared with that of what happened 100 years ago.
Previous beliefs had suggested that the prolonged growing season would mean that the autumn will get delayed and warmer in the upcoming years. But the recent study published in the journal Science contradicts this belief.
Ecosystem ecologist Constantin Zohner and his team of researchers have in fact predicted that “by the end of the century, leaves might even fall off three to six days earlier”. He has compared this calculation with the biological cycle of human beings where we tend to feel full earlier if we start eating earlier.
“This is a mechanism we also see in humans — if you start eating earlier, you will be full earlier,” he said .adding that this will happen because of the restraints that trees have. We cannot expect them to process more and more CO2 just because we are producing more of it.
For the research, the team used a combination of field observations, laboratory tests and modelling to study data collected from six European deciduous tree species. These are the European horse chestnut, silver birch, European beech, European larch, English oak and rowan. The data that spanned for more than the last six decades was studied for the purpose.