As the greens turn to red and gold, the leading expert tree grower, IAN POWELL, takes a stroll in the autumn woods

The great cycle of life turns and autumn is coming on apace.

Traditionally the bounty of the summer fields is harvested but the woods, working to a different, longer rhythm, prepare for the trials of winter and conduct the forest equivalent of battening down the hatches. Most conifers will tough out the winds and hold onto their needles. Most broad leaved trees will opt for the better part of valour and decide to let their leaves go, some more discretely deciduous than others.

The shows of red and gold that we love so much in autumn are an important stage for the trees. The leaves, no longer green, hold nutrients that must be reclaimed by the tree before the burnished leaf can sail on the breeze.

The falling leaf itself is a poetic image of a destiny fulfilled and what could be more evocative of autumn than collecting shiny conkers and wading through piles of rustling leaves? We know that the conkers bear the secret of new life but the fallen leaves also have an important ecological role to play. Generations of leaves in our forests create a layer of mulch which is vital for enriching and protecting the soil. It also allows the trees to maintain some say over what grows beneath them on the forest floor.

Fungi, essential to the life of the woods, are busy recycling the wealth of energy and any minerals that remain in the fallen leaves. The delicate, white webs of fungal mycelia are the foundation from which the showy toadstools spring.

Composting is all around us!

Some fungi work closely with host trees. They reach out into the layers of leaves and gather water and nutrients which are passed to the tree. The tree pays promptly for this service with sugar, the energy for life. This little everyday miracle goes under the name of mycorrhizae. We could learn something from the parties to this symbiotic relationship. Neither has ever tried to cheat the other.

One exceptional family of conifers is the larch. These attractive trees, popular with moths and butterflies, have evolved to become deciduous. The Latin name of the European Larch, native to the Alps, is aptly Larix decidua. Their delicate pale green needles turn yellow and fall before winter. As you take a stroll in the woods this autumn, wrapped up in woollies and fleece, see if you can spot the elegant larch preparing its branches to sing in the winds of winter.

A walk in the woods at this time of year is dramatic for all the senses. The sound of the wind blowing the leaves or sighing through the pine needles is complemented by dramatic shifts of light and the rich smells of the leaf litter. As a tree grower or silviculturalist (an occupation that eludes many dictionaries) I am a little obsessed with the development of roots and the processes of the living earth. Will you join me this autumn in appreciating the humble forest soil? Scratch a little into the accumulated layers of leaves and feel the life that teems there. Breathe in a little decomposition; it is next year’s life in waiting.

Autumn: six seasonal snippets

• There are rare examples of the use of the word autumn as early as the 12th century, but it became common by the 16th century. It originates from the Old French word autompne (automne in modern French), and was later normalised to the original Latin word autumnus.

• The term ‘Indian Summer’ is believed to be derived by the Natives Americans meaning warm, still weather in autumn. It is sometimes called “Old Wives Summer”.

• Deciduous plants were traditionally believed to shed their leaves in autumn because the high cost involved in their maintenance would outweigh the benefits. In many cases this turned out to be oversimplistic — other factors involved include insect predation, water loss, and damage from high winds or snowfall.

• October 2010 had five Mondays, five Fridays and five Saturdays, which only happens every 823 years and the 31st is always Halloween.

• The origin of apple bobbing is unclear; it is not even known when it began. In Scotland this may be called “dooking,” i.e. ducking and in Ireland, mainly C ounty Kerry it is known as “Snap Apple”

• The name ‘bonfire’ is believed to be derived from the Celtic custom of burning the bones of the cattle which were slaughtered at this time