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
Knagenhjelm (noble family) Manor ("Kaupanger Hovedgård") in Sogn og Fjordane and are included in the Yearbook of the Danish Nobility ("Danmarks Adels Aarbog"). Before he became noble, Niels Tygesen Knag had only a tree trunk as his arms (Hans Krag. 1942). The coat of arms was received upon the ennoblement in 1721. Description without the heraldic terminology: "On a blue shield a tilted, chopped and knotty silver tree trunk beside or above which there are three golden stars in each of two bends. On the helmet is a six-pointed star between two buffalo horns divided in gold and blue, vice versa, respectively." Some