Christmas tree pests and weeds of different pests, most of which cause cosmetic damage to the trees, important in the Christmas tree industry. The balsam woolly adelgid ("Adelges picae") are small soft-bodied insects which attack the Fraser fir. The insects appear as white, woolly spots on the tree and are fatal to the fir if left untreated. The woolly adeligid was native to central Europe where it affected the silver fir; it was introduced to the United States, where it has no known native predators, before 1900. Balsam twig aphids ("Mindarus abietnus") are another type of tree pest which affects fir and spruce trees in
Trysting tree smooth bark. The 'Great Fraser Yew' may be as much as 700 years old and once served as the rallying point of the Clan Fraser members in times of trouble. Kelso, in the Scottish Borders has a 'trysting tree' which is connected with the annual Common Ridings. The locally famous trysting place of the 'Three Thorns of Carlinwalk', this being an old name for Castle Douglas in Dumfries and Galloway, are recorded in the Ordnance Gazetteer of Scotland. Robert Burns writes of a trysting thorn tree (see below) at the Mill of Mannoch at Coylton in South Ayrshire. A new