A new study has found that the early greening of urban trees can have negative environmental and economic impacts.
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A new study has found that the early greening of urban trees can have negative environmental and economic impacts.
Cindy Ord / Getty Images
If you live in a big city, you may find trees starting to sprout even before spring officially arrives.
A new article is published in the journal Science found that trees in urban areas begin to green earlier than in rural areas, because cities are hotter and also have more light.
“[I] Author Lin Meng says artificial light in cities acts as an extended daylight and causes earlier spring green color and later fall leaf color.
Meng is a postdoctoral fellow at Lawrence Berkeley National Laboratory. Her research collected observations and satellite data from 85 cities in the United States between 2001 and 2014.
“I see trees starting to grow leaves and green six days earlier in cities than in rural areas,” says Meng.
The researchers found that different types of artificial light in cities like Chicago minimized damage to trees.
Saul Loeb / AFP via Getty Images
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Saul Loeb / AFP via Getty Images
The researchers found that different types of artificial light in cities like Chicago minimized damage to trees.
Saul Loeb / AFP via Getty Images
While the early arrival of spring and longer growing seasons may not seem like a big deal, Meng says there are serious impacts on people, pollinators and wildlife.
First, budding plants are at risk of spring frosts. And changes in the growing season can also lead to an earlier and more intense pollen season, which means people are at higher risk of allergies.
Meng also speculates this could lead to a bigger problem if trees become out of sync with the insects that pollinate them.
“That can lead to food shortages and can affect the growth, survival and reproduction of insects,” she said.
Changing the greening cycle can also have negative economic effects, especially in places that rely on seasonal variations to attract attention, according to Theresa Crimmins, director of the US National Phenology Network. travel.
“Warm temperatures in spring promote flowering which is much more variable,” she said.
“There are a number of situations where across the country many smaller towns hold festivals to celebrate a particular biological phenomenon, like a tulip festival or a lilac festival.”
It is not clear whether the tree will bud earlier than usual.
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Ed Jones/AFP via Getty Images
It is not clear whether the tree will bud earlier than usual.
Ed Jones/AFP via Getty Images
Though worried, Meng says it’s not bad news.
“If we had a longer growing season, trees would absorb more carbon dioxide from the atmosphere,” she said.
“They will have a longer time to implement a cooling effect that can help mitigate the urban heating effect in cities.”
As for the solution, Meng said choosing different types of artificial light would minimize harm to plants, and if light pollution could be eliminated, early greening could be reversed.
