Looking out across the Weald from Newlands Corner this afternoon, we were treated to an amazing display of autumn colour from the trees of Blackheath, Albury Heath, The Hurtwood and Winterfold Forest.
The diminishing daylight hours and falling temperatures in autumn induce trees to prepare for the winter. The shedding of their leaves is preceded by this spectacular show of colour. Green leaves turn to brilliant shades of yellow, orange and red, the result of transformations in leaf pigments.
Trees take carbon dioxide from the air and use sunlight and water to turn it into oxygen and glucose. If you remember your biology lessons this is called photosynthesis. Chlorophyll helps photosynthesis happen and it is this chemical that gives leaves their green colour.
The days get shorter in autumn and as a result there is less light. This is how the trees “know” to begin to get ready for winter. During winter there is not enough light for photosynthesis, trees rest and live off food that they have stored during the summer. As they begin to shut down their food-making factories the green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colours. Small amounts of these colours have been in the leaves all along, we just can’t see them in the summer because they are covered up by the green chlorophyll.
The bright reds we see in trees like Maples is trapped glucose and the brown colour of Oaks trees is made from wastes left in the leaves.
This week The Telegraph reported that Professor Brian Ford, a scientist, writer and broadcaster, believes autumn leaves actually drop in order to excrete waste products from the tree and not because they die off due to lack of light. [Click here for more]
As the weak sun grew low in the sky over Newlands Corner, mist started to settle in the Weald giving us a view of the Surrey Hills that that has been enjoyed, largely unchanged, since the Norman conquest.