Why Spring Comes Earlier in Some Cities

Do you ever wonder why spring comes early in some cities? Scientists finally found the answer and it's not very pleasant.

New science suggests a relationship between light pollution and the timing when trees produce buds, which signals the arrival of the spring season.

Light pollution is defined by Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights. Excessive manmade lights at night result in disturbed natural cycles, and also hinder the observation of stars and planets at night. But its effect on the environment goes beyond that.

By studying a 13-year dataset from four tree species--oak, ash, beech and sycamore. Researchers found out that trees that are more exposed to artificial lighting at night buds up to 7.5 days earlier than those at the natural nighttime setting.

The study focused on non-urban areas to eliminate the effects of higher temperatures which is usually experienced in urban areas. Still, they found out that light had a more significant effect than temperature when the buds emerged.

The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn.

Professor Richard Ffrench-Constant, who helped lead the research, explained to Daily Mail that more than the budding of trees, the study implies danger for the balance of the ecosystem.

"At the moment, caterpillars are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed off the young caterpillar," he said. "If this cascade effect is thrown out of sync, then wildlife is bound to suffer," he added.

Migratory birds are also negatively affected by light pollution. The glare might confuse them and make them lose their navigation sense. The phenomena might explain why some birds accidentally collide with buildings.

Such results emphasize the need to pursue studies that aim to measure the impact of light pollution on phenology and species interactions.

Since the study found red lighting to be the most detrimental, people must be encouraged to come up with a lighting that would be kinder to nature.

If the issue was left to continue, Gizmodo estimates that by 2100, spring would begin almost a full month earlier than it does today.

The research was published in the journal Proceedings of the Royal Society B.