Do you ever wonder why trees begin to bud (发芽) earlier in some cities? Scientists finally found the answer but 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 the Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights.Excessive (过多的) man­made light at night results in disturbed natural cycles, and also prevents the observation of stars and planets at night.But its effect on the environment goes beyond that. By studying some trees, researchers found out that trees that are more exposed to artificial lighting at night bud up to 7.5 days earlier than those at the natural nighttime setting.And they found out that light had a more significant effect than temperature when the buds came out.The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn.Professor Richard, French­Constant who helped lead the research, explained that more than the budding of trees, the study implies the danger to the balance of the ecosystem.“At the moment, caterpillars (毛毛虫) are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed on the young caterpillar,” he said. Migratory (迁徙的) birds are also negatively affected by light pollution.The glare might confuse them and make them lose their flying sense.The phenomenon might explain why some birds accidentally knock into buildings. Such results stress the need to pursue studies that aim to measure the effect of light pollution.If the issue were left to continue, it is estimated that by 2100, spring would begin almost a full month earlier than it does today.