The changing colours of autumn

There are few sites to compare to Hagley Park on a clear autumn morning.

The City Council’s tree officer, Dieter Steinegg, who took these pictures in the park recently, recommends that the best time to enjoy the autumn colour of the trees is on a clear, dry and cool (not freezing) day.

Dieter says that the changes in the colour of the trees’ leaves are the result of a chemical process that takes place as the seasons change from summer to winter.

We asked him to explain in more detail…

“During the spring and summer, leaves serve as factories which produce most of the energy necessary for the tree’s growth. This food-making process takes place in the leaves, which contain chlorophyll, giving them their green colour. Along with the green pigments in the leaves are very colourful pigments.

“Most of the year, these colours are masked by the large amount of green colouring. In autumn changes in the length of daylight and temperature, cause the leaves to stop making food. The chlorophyll breaks down and the green colour disappears. The yellow to orange colours become visible and give the leaves their autumn splendor.

The weather, temperature, light and water supply affect the intensity and duration of the leaves’ colour. Low temperatures above freezing will favour bright reds in maples.

However, early frost will weaken the brilliant red colour. Rainy or overcast days tend to increase the intensity of the autumn colours.

Enjoy the colour, it only occurs for a brief period each autumn and please don’t forget to put the fallen leaves on your compost heap!”