PHIL CALVERT: The magical colours of autumn

In the morning the cars become covered in a thick coating of dew, and down near the river, there is often a thick layer of mist. In the hedgerows, there are coloured hips on the wild roses and the hawthorne and rowan groan under the weight of their crop of berries.

I would think this year will constitute a good year for the production of fruits. It was generally dry during flowering time in May, with only light frost. Pollination would have been very successful. As the flowers matured and fruit was set we drifted into summer. A wet July and August ensured plump berries as the summer grew old and the result is the hedgerows full of fruits. Nature’s larder appears to be full ready for the winter ahead.

The other process which so typifies autumn in our gardens and in the wider countryside is the changing colour of the leaves. It is easy to presume that the further north you go the earlier autumn arrives and there is some truth in this.

In the Midlands, however, where the moderating influence of the sea is much less evident, there are often frosty nights when it is much milder here in Lancashire. I was at a trade show in Telford the other day and the yellows, russets and reds of autumn were far more in evidence than they are round here

Similarly, last Monday, Wifey and I went for a tootle on the bicycles on the Leeds and Liverpool Canal between Bingley and Leeds. In warm sunshine we cruised along the towpath but around Saltaire, beyond the magnificent waterside mills built by Titus Salt and the superb old church, we came across tracts of canal covered from side-to-side with floating beech leaves, cast by the overhanging trees. As the day aged, the clear skies meant we were in for a ground frost as temperatures plummeted.

Over on the Yorkshire side of the Pennines it tends to be colder in winter but generally much drier. On our side of the hills, we catch the the winds that bring clouds bearing rain, lots of it, in from the Atlantic. The result, Lancashire is a wet county especially in the areas of the old mill towns. All that cloud, however, often means milder nights and less frost, resulting in local variations in the progress of autumn. Even so, Monday night was pretty chilly.

Leaves are the powerhouses of a tree, producing simple sugars directly from water and carbon dioxide. As the growing season draws to an end these small powerhouses close down and are cast off. Leaves are a key to a tree’s ability to draw moisture up from the ground. Leaf fall occurs mainly as a preparation for the time when ground water becomes frozen and inaccessible and as a response to the trees lower matabolism anyway.

The leaves are actually denied water by the formation of a watertight boundary, called the abscission layer between the branch and the leaf stem, and it is here the brittle joint forms prompting leaf fall. As this layer builds up, the useful constituent parts of the leaf’s chlorophyll are drawn back into the main body of the tree to be stored for next year. As the chlorophyll is depleted, other compounds, previously masked, become more apparent, and it is these compounds which are responsible for the leaf colours we associate with autumn.

The most commonplace are the compounds known as flavenoids, which are yellow, but it is the less common carotenoides which generate the oranges and reds. These are especially obvious in purple-leaved shrubs such as the Japanese Maples (Acer palmatum types), but they occur in many trees and shrubs.

As you drive along the M65 the change in leaf colour is already apparent and I love the transformation of the landscape prior to the colder harsher months of winter. Maples, generally, are perhaps responsible for the showiest autumn colours. However, many cherry trees too brighten up the autumn with their leaf colours.

Outside my own house we have mature chestnut, beech and sycamore trees and all carpet the street in a generous carpet of leaves. Being a bit fussy, however, I enjoy the leaves as they lay on sunlit dry days, but I get quite keen to clear them away with a leaf blower before the onset of wet weather and their transformation into a dirty mush. While the weather holds, however, they look spectacular.

Mind you, there is an element of waste-not, want-not here. The leaves I collect up in the mower from the lawn, I store in the compost bins to break down into the dark crumbly material known as “leaf-mould” which is an excellent soil improver, especially on our heavy clay soil. The battering the fallen leaves take from the mower helps speed up the composting process.

All in all, the onset of autumn is a time to cherish, to enjoy the final display of the growing season. Whether you are walking the shores of Windermere, strolling along the canal towpath or walking the dog through Hagg Wood, autumn is a magical time to get out and about. Enjoy it while we can! Dark days lie ahead.