Tree from the cinchona tree ("Cinchona") and was for a long time the remedy of choice for the treatment of malaria. Aspirin was synthesised to replace the sodium salicylate derived from the bark of willow trees ("Salix") which had unpleasant side effects. The anti-cancer drug Paclitaxel is derived from taxol, a substance found in the bark of the Pacific yew ("Taxus brevifolia"). Other tree based drugs come from the paw-paw ("Carica papaya"), the cassia ("Cassia spp."), the cocoa tree ("Theobroma cacao"), the tree of life ("Camptotheca acuminata") and the downy birch ("Betula pubescens"). The papery bark of the white birch tree
Bark beetle economic impact. In undisturbed forests, bark beetles serve the purpose of hastening the recycling and decomposition of dead and dying wood and renewing the forest. A few species are aggressive and can develop large populations that invade and kill healthy trees and are therefore known as pests. Bark beetles of the family Scolytidae feed and breed between the bark and the wood of various tree species, including spruces. More than 20 species feed on weakened, dying, or dead spruce, fir, and hemlock. Most restrict breeding area to one part of the tree: twig, branch, stem, or root collar. Some breed