Spread of beetle leads to curbs on Lakes timber

Curbs on the movement of timber have been introduced to Cumbria after more than 20 woodlands were found to be infested by a tree-killing beetle.

Routine surveys have revealed that the great spruce bark beetle, a known pest to forests, has spread to 23 sites in the Lake District.

Woodland owners are being warned of the outbreak. Two restricted zones on conifer wood and bark have been established around Windermere while the Forestry Commission tries to gauge the extent of the outbreak.

The species has been established in Wales and adjoining English counties since about 1970. With the exception of an outbreak in Kent in 1996, it has been contained through biological control and restrictions on the movement of conifer wood.

The great spruce bark beetle, or Dendroctonus micans, lays its eggs under the bark of spruce trees, with insects feeding on the inner bark layer. As neither the beetle nor its larvae burrow into the wood itself, the timber is not spoilt as long as it is salvaged before the tree dies. The trees suffer long-term infection, with destruction spread over a number of years.

Roddie Burgess, head of the Forestry Commission's plant health service, said there were two main ways in which the beetle could have spread. He said: "It might have been by natural means, such as beetle flight, or it might have occurred through the illegal movement of infested timber of wood debris, such as branches or bark residues, on timber wagons or harvesting machinery travelling from long-infested areas to the Lake District."

The main way of containing the pest is by introducing another beetle, Rhizophagus, which attacks only the great spruce bark beetle.