Have you stopped to admire nature’s free show?As trees, bushes and hedgerows display their rich palette of autumn colours: red, yellow, brown, purple, pink orange and gold.

We experience these changes every autumn, perhaps without considering why they happen. Why do leaves change from green and where do the ‘new’ colours come from?

Surrey is officially Britain's leafiest county, which is lucky for us. Wherever you live or happen to be, you’ll not be far from a fantastic display of autumn colour.

We can think of leaves as a tree’s solar panels, collecting sunlight together with carbon dioxide from the atmosphere. Leaves contain a chemical called chlorophyll which uses light to turn carbon dioxide into the energy the tree needs to grow – a process called photosynthesis.

The products of this process are carbohydrates (sugars) which are carried into the tree’s vascular system, and oxygen released from the surface of the leaves into the atmosphere.

Chlorophyll is also the pigment that gives leaves their green colour.

The leaves of deciduous trees, shrubs and bushes that change colour during autumn and are shed for the winter. By contrast, evergreen trees such as pines survive colder weather differently and keep their leaves over the winter.

The change in a deciduous tree is down to hormones: it notices the days becoming shorter, so there is less light available and the temperature drops.

It would be a great effort for the tree to continue supplying its leaves with nutrients throughout the winter, so it responds by shutting down its metabolism. Think of it as going into a kind of hibernation.

It also stops producing chlorophyll –its green pigmentation – so the leaves change colour. The colours revealed are due to chemicals called carotenoids and xantophylls, which are yellow and orange in colour.They were in the leaves all along but were invisible due to the green chlorophyll. Now we can see those colours in their full glory. 

The red and pink colours in some leaves are due to other chemicals called anthocyanins, formed in leaves as a by-product of changes in the tree’s physiology. It is especially noticeable in acers, a genus of trees and shrubs also known as maples.

Looking out of my window I see a Norway maple tree and Japanese acers all exhibiting red, pink and gold leaves. As well as leaves that are still green because chlorophyll production hasn’t yet stopped completely.

While these changes are happening, the tree moves important chemicals from its leaves to twigs, trunks and roots, to be stored until spring when it bursts into life again.

As I write, many trees are already on the turn, but I’ve not yet seen the range of colours of previous years. The temperatures during October were mild which will have caused trees to delay the change. This may also result in a shorter period of autumnal colour before trees lose their leaves.

I find most interesting colour displays are where there is a variety of trees, which change colours at different times and into a greater variety of hues. My photos are in Goldsworth Park which was planted ornamentally with a wide variety of tree species when it was developed in the 1970s-80s and retains many ancient trees.

Enjoy the colours while you can: a single storm can strip trees bare and it will be a whole year before nature repeats the spectacle.