It also suggests the amount of aerosols that humans emit into the atmosphere could impact tree growth, as high levels of aerosols cause "global dimming", an effect that occurs when the levels of light reaching the Earth's surface fall.

BBC: Earth News - Cosmic pattern to UK tree growth

"If it is true that the mechanism is all about rays enhancing diffuse radiation, it would mean that 'global dimming' and 'global brightening' would have a big effect on tree growth and therefore on the absorption of carbon dioxide, " warns Ms Dengel.

BBC: Earth News - Cosmic pattern to UK tree growth