New Forest rangers have introduced the pigs in the hope they provide offer a greener alternative to herbicides in the fight against gaultheria shallon, known locally as American strawberry.
Eleven Tamworth pigs were left to do what comes naturally - snuffling and rooting freely through the soil, tearing up the roots in an 18-yard square covered with the shrub close to Rhinefield House, near Lyndhurst, Hants.
To encourage the porkers to get to work, pig nuts were scattered around the enclosure. After a month's hard rooting, the entire area has been ploughed up. The pernicious American strawberry has, for the time being, been vanquished.
"A pig's nose is one of the finest excavators known to man," said Forestry Commission ranger Vicky Myers. "It's definitely worked but we now need to decide how efficient they've been. They are young pigs and they took a while to work out what to do."
For the most part, the pigs have eaten the thick layer of bracken that carpets much of the forest, rooting out the American strawberry at the same time. Their work will help reduce the use of weed killers such as Roundup or Timbrel in the forest, which is Europe's largest surviving area of ancient pasture woodland. Miss Myers said: "The enclosure runs down to a valley mire and wetland, herbicides could go into the water.
"Even though herbicides are approved, we'd really rather not go out and drench the plants in the stuff if we can avoid it."
Elsewhere in the forest, the shrub remains a problem. It was introduced a century ago from the Pacific North-west of the United States, either to provide pheasant cover or as an ornamental garden shrub. It grows four feet high and in its native land the black berries provided part of the native staple diet.
But the shrub now covers some 50 acres of the Fletchers Hill enclosure spreading by an intensive network of shallow roots. The trial concludes this week and a team of environmentalists and experts from the Forestry Commission will decide just how effective it has been. Next year, the trial is expected to resume on a larger scale, with bigger pigs who may eat the shrub.
Pigs are an integral part of the New Forest. Under laws from the time of William the Conqueror, pigs owned by commoners - people who live and work in the forest - roam free in autumn, cleaning the forest floor of acorns which can be harmful for the forest ponies.
At such times, the pigs wear nose rings to stop them digging up the entire forest. The ones in the trial, which were supplied by a commoner, do not have rings, enabling them to forage at will.
The scheme is operated by the Forestry Commission, which runs the New Forest on behalf of the Queen, as part of a pounds 5m project which aims to help regenerate the woodland and clear 160 hectares from aggressive species, which include turkey oak, sycamore and rhododendron. It also aims to provide support for commoners. "The funding means the forest is recognised for its conservation value," said Miss Myers. "It will allow us to plan the forest for the next 100 years."Reuse content