In the 1930s, more than 30% of Ethiopia consisted of forests, but that total has fallen to 13%. Boswellia and species of commiphora produce gums used as the basis for frankincense and myrrh, respectively. A species of acacia is a source of gum arabic. Eucalyptus stands, introduced in the 19th century, are a valuable source of firewood, furniture, and poles. Roundwood production was an estimated 89.9 million cu m (3.2 billion cu ft) in 2000; all but 2.5 million cu m (88 million cu ft) was for fuel.