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Each year, in a process known as aging, the leaves of deciduous trees turn yellow, orange, and red because they stop growing and extract nutrients from the tree’s leaves, before they fall off the tree before winter. Leaf aging also marks the end of the period during which plants absorb carbon dioxide through photosynthesis.
The researchers said global warming has led to longer growing seasons – spring leaves appear on European trees about two weeks ago, compared to where they were 100 years ago.
“Previous models assumed that as autumn gets warmer in the next century, autumn will be delayed: growing seasons will generally be longer and autumn will be delayed by two to three weeks,” Konstantin said. Zonner, an ecosystem ecologist.
However, Zohner and A team of researchers said the results reflect this expectation.
“We already expect, by the end of the century, that the leaves may have fallen before three to six days,” said Zonner, the corresponding author in the newspaper published Friday in the journal Science.
Using a combination of field observations, laboratory tests and models, the experts studied data that tracked six types of European deciduous trees – European horse chestnut, silver birch, European beech, European pine, English oak, and rowan – over the past six. decades.
Experts have found that spring and summer productivity increases that result from rising carbon dioxide, temperature and light levels cause trees to lose their leaves early.
Zonner said low temperatures and day length are the main environmental factors that cause tree leaves to shed. Now, the researchers have identified a third factor: “self-limited” productivity.
“What we are seeing now is that there is a third huge mechanism going on: productivity (the tree) is shrinking. If you have more, this actually happens in spring and summer: if the plant absorbs more carbon dioxide in synthesis during spring and summer, it loses its leaves soon. “.
“This is a mechanism that we also see in humans: if you start eating early, you will be full soon,” he said.
Zoner said the results showed trees have productivity limitations.
“We can’t put more and more carbon dioxide into the atmosphere and (expect) trees to do a lot more – there are limits,” he said.
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