Killing trees to save water; S. Africa hunts down aliens
By Clare Byrne, dpa Tuesday, March 9, 2010, 10:44 am TWN
Cape Town -- On the upper slopes of Cape Town's landmark Table Mountain on a windy morning in summer, the "Tree Taliban" are hunting down alien invaders.
Clambering through a dense thicket of shrubs and brambles, government workers in blue overalls and yellow construction helmets are scanning the area for non-indigenous trees, like the black wattle.
When they find one of the small, shrub-like trees, they hack at the stem with a saw exposing its white innards and then spray the gash with a red-tinted herbicide.
Soon the tree will keel over and die.
Few know that South Africa, one of the world's biggest per capita emitters of climate-changing gases, has a state program to kill trees.
After all, trees act as carbon sinks — which suck up carbon dioxide, the main greenhouse gas — and South Africa is trying to rein in its emissions.
But non-indigenous species of trees like the eucalyptus or the black wattle — natives of Australia — were planted by settlers for timber, mining and other purposes. They also guzzle water at a much faster rate than a water-stressed country can spare.
With experts predicting that average global temperatures will rise by at least 2 degrees Celsius by 2025, water in drought-prone southern Africa is expected to become even scarcer.
The 2007 report by the Intergovernmental Panel on Climate Change predicted that between 75 and 250 million people in Africa would be exposed to increased water stress due to climate change by 2020, impacting food production and general development.
In this climate, reducing and offsetting a nation's water footprint may be just as important as managing its carbon footprint.
"More water is more important at this point for South Africa," says Rodney February, project manager of the World Wildlife Fund's Water Neutral Programme.
Modeled on the concept of carbon neutrality, the program measures a company's water usage and proposes ways to both reduce it and offset it by investing in projects that increase supplies of fresh water.
Alien plants in South Africa are estimated to use 3.3 billion cubic meters of water a year — the equivalent of the water flowing through 26 large dams.
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