Here's Why Leaves Change Colour In Autumn, And No, They're Not Just Dying

You’ve noticed it too, right? There’s been a nip in the air recently, and a change in the evening light ― you’ve probably seen a couple of leaves falling down, too.

The second I see my first autumn leaf, I instinctively want to pull my sleeves over my knuckles and hold a mug of tea with both hands like those ladies in ads.

But even if your reaction isn’t as intense, you’ve probably at least wondered to yourself why it is that deciduous leaves change hue in the first place ― and if you simply thought they were dying, you’re not quite right.

So what’s actually going on?

According to Forestry England, leaves are bright green in the summer because they’ve got lots of chlorophyll.

“Chlorophyll helps trees to absorb the energy of the sunlight - the tree is essentially ‘charging’ during the summer months,” their site reads. 

When trees begin to get less light in the autumn, chlorophyll breaks down and the tree doesn’t bother replacing it. 

Chlorophyll was sort of “covering” the leaves’ underlying colours in the summer, and as it goes away, you get to see the reds and yellows that were actually there all along. 

These colours are created by xanthophylls and carotenoids, which again are found in leaves year-round. 

Fiery red anthocyanins cause vibrant scarlet hues, and are only released when there’s been a lot of sunlight that summer. 

The tree’s sap gets more concentrated, so the anthocyanins are activated in the hopes of drawing every last bit of energy from their leaves. The same process has been noted in extremely cold climates.

But... the leaves do die, right?

They do, yes.

A lack of chlorophyll spells big trouble for deciduous trees, so the colour-changing process isn’t just a RuPaul-esque reveal of their usually hidden undertones ― the leaves are going through the end of their life cycle. 

While we have you, though, there are more reasons than you’d think to hold onto the fallen leaves. 

They can make amazing compost and may provide a much-needed home for animals who desperately need shelter in the colder months. 

I can’t be-leaf (sorry) how much more interesting leaves are than I thought...