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.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
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.
- Try your first 6 issues for just £9.99 when you subscribe to BBC Science Focus Magazine.
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
- Stay up to date with the latest developments in the worlds of science and technology.