Autumn blazing in gardens

This kind of weather tends to produce better than usual autumn colour in deciduous trees and shrubs. The Irish climate never manages to produce quite the intensity of colour that they have in the eastern US or Japan, even among American or Japanese species that are planted here, but some autumns are brighter than others and this is shaping up to be a bright one.
Walking through my little wood I noticed something odd. There were two young sycamore trees about 20 metres apart. I planted them on the same day and they are of the same age and provenance but they looked completely different. One was a blaze of pale yellow leaves and the other was a dowdy dark green. They had both experienced exactly the same weather conditions but they had reacted differently to them.