Fall, November 2016
By Sandra Gibson
Photographs by Geoff Edwards
Just when small creatures are planning their hibernation, the turning and dropping of the leaves awakens our inner poet to a multi-sensory experience. The colourful beauty of autumn leaves takes us on pilgrimages, where swirling leaves map the movement of air as we crunch or squelch through piles of brittle or sodden vegetation, releasing the earthy, fungal, smell of decay.
That the foliage is at its most beautiful at the perishing moment is a poignant image of life’s brevity, and although we know that there will soon be new buds, there is still this elegiac pause, reinforced by increasing darkness and the sorrow of the Cenotaph.
But why do deciduous trees shed their leaves? Basically, it’s a matter of fuel economy. In the days of plenteous light and heat, leaves interact with sunlight to produce energy to feed the tree, which in turn feeds the leaves with nutrients from the ground. Once light and warmth diminish, and the cold desiccating winter winds approach, photosynthesis is curtailed and the danger of dehydration increases. So the tree cuts its losses by secreting chemicals which cut its leaves off at the stem: it can no longer lose moisture through them and no longer has to feed them. So it remains economically dormant until days lengthen and warmth returns.
Now this doesn’t have the poetic ring of autumn as a dying beauty but the cyclical nature of the process of leaf fall has its own beautiful equipoise. The discarded leaves decompose at the base of the tree, enrich the soil and feed the mother tree so she can nourish the spring buds. In some trees, the absence of leaves aids pollination of flowers born on bare branches before leaf-burst.
Trees growing in urban areas often have limited exposed earth around them, so there are deposits of leaves on pavements, with no soil to absorb them. Thus, part of the cycle is incomplete and town trees do not benefit as much as country trees from natural self-enrichment. I have often swept up such leaves for my own compost and nothing is better for peas and beans than this. It would be good to see more people ‘harvesting’ the leaves from our streets for their own gardens and allotments. This would complete the interrupted cycle, though in a different place, whilst at the same time tidying the communal environment.
Meanwhile: yellow and red leaves are skipping and swirling and looping and changing leaders all around and all along the ground, like storybook children. This is good too.
*Also known as Rose Bay Willow Herb, the prolific wild flower called Fireweed, five feet tall with spikes of magenta flowers, cheers the hearts of those whose cityscape has become a bomb site or whose buildings have been cleared by machine. The dormant seeds spring to life after destructive events such as forest or man-made fires, hence the name, Fireweed. This occasional column will celebrate the persistence of wildlife in urban conditions.