Travel and trade are the main drivers of the introduction of exotic species into new areas. To explore the role of wood trade in the potential introduction of tree pests, we developed a pathway model and calculated the exposure of trees in Europe to tree pests. The model describes the import, inspection and treatments of wood, as well as the trade among European countries and processing to sawn wood, final product and residues. The model quantifies the frequency of escape of the pest from wood, and the transfer to host trees. This model was designed to be generic, but for illustration, it was applied to round wood of oaks coming from the United-States of America potentially carrying the oak wilt fungus, Ceratocystis fagacearum (not present in Europe yet) and to round wood and sawn wood of conifers coming from China potentially carrying the pine wood nematode, Bursaphelenchus xylophilus (detected in Portugal in 1999). We show that this pathway model can be used to identify the points along the pathway which mainly contribute to the exposure and to test the effectiveness of various risk reduction options. Pathway modelling is a promising tool to study entry pathways of alien tree pests. First, it is useful to target the data which are necessary to collect to better assess the exposure. Then, it can assist plant health managers in pest risk analyses and support decision makers in their decisions about trade regulation and associated conditions.Read less <