The NHLA’s warning follows a US Development Agency Animal and Plant Health Inspection Service alert about EU customs authorities looking more closely at US lumber imports following recent publicity surrounding invasive pests and plant health in Europe.

The NHLA has told members there was now an increased risk of US lumber shipments being refused entry to Europe if the lumber failed to meet strict rules.

"Exporters are advised to be extra vigilant to ensure that if the additional declaration referring to heat treatment or kiln drying is on the phyto certificate, the mark must also be clearly visible on every bundle of lumber," said the NHLA.

The advices relates to shipments of oak, maple, plane, poplar/aspen and sweet chestnut.