Why do leaves change colour in autumn?
While we stock up on tea and hot water bottles to prepare for winter, trees get busy recycling.
Asked by: Davina Taunton, Ledbury
Deciduous trees drop their leaves to reduce water loss during winter, when it is too cold to grow. But rather than just discard the entire leaf, the tree recycles as much of it as possible, to conserve nitrogen. The green chlorophyll is the first to be broken down and reabsorbed, which allows yellow carotenoids and red anthocyanin to show through.
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.