Conservation: This little piggy saved a forest

How piglets replaced weedkiller in Yorkshire. By Helen Lewis

Suffolk 1990, and a small group of 11-week-old piglets swap piggery for pine-scented forest for a few months. The idea behind the move? To see how they would adapt to woodland life; whether they would turn their snouts up in disgust or delight in the chance of grubbing around under the trees.

As it happened the pigs took it all in their stride, devouring brambles, bracken and fern with great gusto, rummaging amongst the forest floor and growing fat in the process.

One very pleased farmer subsequently sold these swine at a premium price as organic, free-range pork. This just left the Forestry Commission to decide whether the pigs had proved a worthwhile alternative to their usual - if environmentally unseemly - chemical and machine regime of weed clearance and soil preparation.

The pig experiment was deemed a success and in 1993 the first large-scale forest pig farming trial got underway in a 62 acre gale-damaged woodland in North Yorkshire.

"Severe storms in 1990 had decimated three-quarters of the trees and the forest floor had become swamped with weeds, so we had to do something," explained Alan Beardsley, Chief Forester, North York Moors District. "Our usual procedure would be to kill the weeds with herbicides, cultivate the ground with machines and finally plant the area with young saplings, but we hoped the pigs would do all this for us," he said.

Firstly, though, the Forestry Commission had to find a pig farmer with enough pigs who willing to take up the challenge. Ian Moulds jumped at the chance and provided around 450 pigs to munch away at the forest undergrowth until March this year:

"The cost of renting arable land was rocketing so, when the Forestry Commission approached me with a cheaper alternative, I grabbed it. Also, the forest offered shelter from the weather, was free from disease and well drained - all essential requirements for pigs," he said.

This pioneering project seemed a perfect solution all round and was wholeheartedly approved of by the Foundation of Ecological Ground Cultivation. By grazing, grubbing and excreting, pigs cultivate the ground and supply it with nutrients. They also make it easier for the tree seeds to put down roots, and help prevent weeds reoccurring.

However, the earthy sound of grunting becoming commonplace in British forests is still a long way off. For all its success, the project had numerous problems. From the pig management point of view it was a nightmare. The number of animals in a given area of wood had to be carefully planned to prevent damaging the existing trees, and poor access made the job of seeing to the pigs' welfare very difficult.

"The trick was to give the pigs enough undergrowth to chew so they would leave the trees alone," Mr Moulds explained. "Apart from worrying about tree damage, looking after the sows at farrowing time, weaning the piglets and bringing the boar in proved extremely difficult - I couldn't get a tractor and trailer in to move the animals with all the tree stumps in the way.

"Basically, the whole idea was not as simple as it first seemed and although I would rent cleared forestry again, this would only be feasible for sows during pregnancy, with accessible grassland nearby for farrowing, mating and weaning when they need to be closely watched," he said.

For all Mr Moulds' efforts, the pigs did harm some trees. They up-rooted small birch, chewed bark and rubbed soil into some of the larger trees' roots. Whether these will survive this damage or succumb to fungal attack won't be known for another couple of years.

Despite these set-backs, Colin Olsson - head forester for the region - admitted the forest floor had been left in very good condition for receiving seeds from both falling pine cones and those which passed through the pigs. Hopefully these will germinate and produce a tree crop without the Forestry Commission lifting a finger.

"The main benefit to us is getting a crop of saplings growing naturally. However, the germination of tree seeds is notoriously slow and unreliable - we may even end up with none at all. If this happens, the weeds will return and we will have to re-plant the wood ourselves which defeats the whole object," he explained.

Despite his misgivings, when Mr. Olsson checked the site at the end of July this year,he was surprised to find nearly a full crop of saplings, including Corsican pine, Japanese larch and birch, already growing. This was a far better result than he ever imagined, but he is still cautious about calling the trial a complete success:

"A lot can go wrong even now. We only need another drought like last year, or an extreme winter, for all these tiny saplings to die. Although it looks very promising I won't give the green light for more pig clearing projects for another 12 months.

"However, if the trees continue to grow this will show that there is great potential for pigs clearing small woodland areas under continuous cover [where 25 per cent of the mature trees are left as protection for the young saplings until established], where the operation can be tightly planned and controlled. But, I don't see animals replacing machines and chemicals on large tracts of forestry just yet," he said.