• Fast-growing eucalyptus has good commercial value but it also reduces soil fertility around itself
• Eucalyptus should only be planted at least 50 metres away from rivers, streams and wetlands
Kisii Governor James Ongwae wants the police to help him cut eucalyptus trees near rivers and in water catchment areas (see P29).
He says local rivers are drying up because eucalyptus has been planted on river banks when they should be at least 50 metres away.
Ongwae is right. Eucalyptus is a water guzzler that can dry up rivers. These trees have been planted illegally as they are too close to the river. They should go.
County governments need to consider very carefully the impact of eucalyptus. For instance, Kilifi is allowing a new commercial plantation of 1,000,000 eucalyptus trees but this will deplete the water table and suck salt water into the soil, thereby reducing agricultural yields for small farmers.
Even on small farms, eucalyptus should be treated with caution. It is fast-growing with good commercial value. But it reduces soil fertility because it is 'allelopathic' as it injects chemicals into the ground to undermine competing plants. So small farmers should plant a mix of trees, not just eucalyptus on its own.
Ongwae be commended for his initiative and other counties should emulate him.
Quote of the day: "Unrestrained competition can drive people into actions that they would otherwise regret."
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