How Does Light Pollution Affect Trees?

As light pollution constantly increases, so do the problems that come with it. Sleep disorders and a greater likelihood of depression are amongst the problems for humans – as well as the huge financial bearing.

The impact is considerable for nature too. Nocturnal animals like owls use the darkness of the night for hunting. The artificial light completely messes with their body clock. New research has even found that trees can be tricked by the constant bright lights.

The city that never sleeps

The skies around more and more urban spaces are becoming polluted with constant artificial light throughout the night. It results in light night-time skies that are causing trees to bloom earlier than they usually would, researchers have found.

The study was led by entomologist Richard Ffrench-Constant, and looked at the blooming schedule of four different tree species:

• European sycamore
• European beech
• Pedunculate oak
• European ash

Using satellites, they could track the artificial light intensity at the locations of each tree. Of course, temperatures were controlled to avoid multiple variables in the experiment – particularly difficult with the heat from the artificial lighting.

Premature blooming

The results of the experiment were fascinating. Three of the four tree species were affected – all except European sycamore. The affected trees budded days earlier, with European ash coming into bloom up to a week ahead with artificial lighting. So the night skies full of artificial lighting may have be tricking a lot more trees worldwide.

Even though the temperature was controlled for this experiment, it may be a further cause for trees blooming earlier in a natural environment, Ffrench-Constant reported. With global warming causing the earth’s atmosphere to rise in temperature, trees could have more than one factor causing their early blooming in future.

The accelerated blooming of trees has a bit of a domino effect. Some insect species, such as the winter moth caterpillar, rely on early spring leaves to survive. So the early budding is actually ideal, giving these insects more time to hatch. Certain birds then use the hatching of the caterpillar to time the hatching of their eggs to ensure there’s plenty of food for their offspring.

Allowing birds to continue to reproduce is important for science because they give us so much information about the evolution of the earth. It’s thought that birds might even have evolved from dinosaurs. The potential link between these two species comes from the analysis of dinosaur fossils, which is explored in ‘Mass Spectrometry Analysis of Dinosaur Fossils Strengthens Evolutionary Linkages’.