Eucalyptus globulus (Blue gum)
Blue gum plays an outsized role in human civilization and reveals how a tree with gifts of economic value can aid and also harm the surrounding living system. A fast-growing tree, the Tasmanian blue gum, in the Myrtaceae family, was introduced in the US from native Australia in 1853, to rescue the country from a ‘timber famine’. Blue gum reproduced and spread quickly, with stands tripling in size in a 70-year period. Both China and Brazil planted six million trees for timber and oils. The capital city of Addis Addiba used to be migratory city until they planted blue gum, which provided firewood and leaves, and started an economic boom. And yet, Eucalyptus draws nutrients from the soil, and in plantations and large stands, they deplete soils, prevent native plants through allelochemicals, and reduce crop production from soil exhaustion.
Few insects eat Eucalyptus because of a lack of nitrogen and presence of essential oils. Though monarch butterflies overwinter in large colonies on Eucalyptus, studies suggest that they prefer native pine tree species when present. Studies of species richness of birds on both eucalyptus and oak in California reveal that many species utilize both, though non-native birds tend to prefer eucalyptus. Eucalyptus leaves were discovered to cure malaria, and in Egypt, it was illegal to pick leaves from street trees, as demand was high. In bush medicine of the Aborigines in Australia, eucalyptus was a favored cure for fevers, infection, burns, and more.
Elizabeth Oriel 2022