The tradition to blaze trees to mark trails and boundaries is very old in northern Scandinavia. The disappearance of culturally modified trees (i.e. trees with trail blazes) and changes in forest structure along a section of an old bridle trail in boreal Sweden was analyzed using historical maps and forest surveys from the period 1876 to the year 2000. Remaining blazed trees were located during a field study and selected scars were dated. In total 104 scarred living and dead trees were found. The scars originated from the early 1500s to the early 1900s. Analysis of the forest surveys showed that the forest along the trail was dominated by older trees, and that the majority of the scarred trees probably were present, throughout the 19th century. By the mid 20th century logging had begun to affect the tree age along the trail and in 1974 no stands older than 180 years were present. A conservative estimate shows that around 90% of the original blazed trees have vanished. The trail was interpreted as have being lined for centuries with scarred trees which gradually have been destroyed during the 20th century. Culturally modified trees constitute an unique source of information for understanding pattern of old trails as well as of past human land use and movement in the landscape prior to the 20th century. This biological archive have to a large extent been destroyed by forestry activities and it is therefore very important to survey, recount and protect the trees that are still present.