For almost 25 years, Dr John Barkham, an ecologist at the School of Environmental Sciences at the University of East Anglia, has studied wild daffodils and their responses to changing environments. His research is producing insights into how best to manage ancient woodlands - those more than 400 years old - where the daffodil, Narcissus pseudonarcissus, is a native species.
Wordsworth, wandering lonely as a cloud, may have considered nature responsible for the 'host of golden daffodils . . . fluttering and dancing in the breeze', but Dr Barkham has demonstrated that human intervention is the key to a flourishing population of the woodland variety. And the key is the traditional practice of coppicing.
For hundreds of years, Britain's woodlands were an important economic resource, providing fuel and building materials. About once every decade, trees were coppiced - cut to stump level - to encourage new growth. Coppice management was largely abandoned last century, when cheap alternative materials, such as coal, became available.
'What happens immediately a wood has been coppiced is that the canopy is cleared and ground flora is suddenly exposed to high light and direct rainfall,' Dr Barkham says. 'There is a rapid degradation of litter on the ground to increase the availability of nutrients. The following year you get masses of flowers.'
This exposure to light enables daffodils to grow from seed, rather than from the parent bulb, thus encouraging the plants to spread. In Brigsteer Wood, Cumbria, Dr Barkham noticed that daffodils growing in the shade did not spread in a uniform carpet. When he planted seeds in the resulting gaps the plants failed to establish themselves; but bulbs, which have stronger shoots, did grow.
However, propagation solely through bulbs - called 'clonal' growth - cannot spread a population; the new growth occurs in clumps around the parent plant. But seeds can be dispersed on the air to establish new plants some distance from the parent.
'The plants growing from seed need a pulse of high light to get over the initial vulnerable four- or five- year period when they are small,' Dr Barkham says. 'So the high light levels after coppicing give the population a boost. There is no chance of the gaps being filled during the shaded phase.'
Growth from seeds also builds into the population a degree of genetic diversity, because the seed arises from the fertilisation of one plant by pollen from another. All communities of organisms benefit from this diversity. Clonal growth, however, cannot introduce these new characteristics.
Dr Barkham's work can be applied to other native woodland plants, such as the bluebell and wild garlic. 'While it is clear that a neglected wood will not lose all of its ground flora,' he says, 'the more shade-tolerant species will tend to dominate. Coppicing results in a much greater variety of wild flowers.'
Flowers are not the only beneficiaries. 'Most of our rare woodland butterflies have become dependent on the regular creation of open, sunny patches of woodland,' Dr Barkham says. And the abandonment of coppicing has had a detrimental effect on some migratory birds, including nightingales and blackcaps. Neglected woods tend to be dominated by common native species such as the robin and blackbird.
While coppicing is becoming accepted as the best way to manage ancient woods, problems inevitably arise. Brambles, for instance, can take advantage of the high light levels and dominate the ground layer.
The biggest drawback, however, is the technique's cost as a highly labour-intensive, time-consuming activity. Encouragingly, some small businesses have been set up to sell wood products derived from coppicing, and Forestry Commission grants are becoming available.
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