For thousands of years, trees and humans have maintained an intimate connection. It’s therefore not surprising that many tree species were moved around the world, following the footprints of human civilisation.
Globally, however, more tree species are becoming invasive, with detrimental ecological and socio-economic impacts. Understanding their invasion history and ecology is essential to developing effective management approaches.
Vast areas of Africa’s southernmost country are characterised by invading tree species. These include wattles, pines, mesquite and eucalyptus. Such invasions are especially worrying in drought stricken South Africa because most invasive trees use more water than other plant groups.
Among the invasive trees with the most severe effects, particularly when it comes to water consumption, are several Eucalyptus species. More than 200 Australian eucalypt species have been introduced to South Africa since the 1800s, most for forestry growth trials and cultivation. They are fast growing and useful – providing timber, paper, poles, firewood, shelter, ornamental value, and nectar and pollen for bees.
Some species, however, escaped cultivation and started to establish populations outside plantations. There are six eucalypt species listed as invasive by the country’s environmental legislation: forest red gum, karri, river red gum, saligna gum, spider gum, and sugar gum. Their listing means they should be controlled or retained, depending on the habitat in which they occur.
Invasive eucalypts account for 16% of the 1,444 million cubic metres of water resources that South Africa loses every year due to invasive plants.The full article is for subscribed members only. To view the full article please subscribe. It’s FREE!Log In Register
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