Last week was World Wetlands Day. This got me thinking of the causes and effects facing our diminishing wetlands. How and where it all started.

The eucalyptus was introduced to the country in 1896 during the construction of the Kenya – Uganda Railway. The construction of the railway and buildings was depleting indigenous tree sources and exporting timber would incur a very high cost for the country. Eucalyptus seed and seedlings were therefore introduced to Kenya from South Africa to serve as material for the railway.

Overtime, the tree has been used in other commercial areas such as buildings, utility poles and as a fuel source for tea production. The trees therefore became important in the economy set up of the country due to its fast growth rate and availability.

Eucalyptus was also used to drain marshes where buildings, farms and grazing land were set up. This was the beginning of a disaster, a future mess.

Eucalyptus became highly harvested in the country. Chunks of land and resources were used to grow it. The government also encouraged its citizens to invest in eucalyptus plantations to ‘build the nation’ (“A Guide to On-Farm Eucalyptus Growing in Kenya”, December 2009. Available at http://www.wrm.org.uy/countries/Kenya/Eucalyptus_guidelines.pdf). Money not only grew on trees but became a fully grown and matured tree.

Eucalyptus trees, use up to 200 litres of water a day according to a research done by the World Agroforestry Center. This makes the species a very ‘thirsty’ tree. This does not favor any water sources, especially wetlands and marshes.

The eucalyptus leaves are not edible by most animals since the essential oil extracted from eucalyptus leaves contains compounds that are powerful natural disinfectants and can be toxic in large quantities. However, the Koala bear, some species of possums, sawfly and the Giant African Millipede are tolerant to the toxicity of the leaves. This does not make it an ideal species in the Ecosystem where the tree has being introduced as an exotic species. The limited number of animal species who feed on the leaves result to little or no undergrowth as the leaves will fill the earth preventing growth.

Effects of Eucalyptus Plantations on the environment

Nature always fights back as it does not tolerate a vacuum. Over the years, we have the seen the effects of not only the eucalyptus but also other exotic trees that have been introduced to the country. Some of the effects experienced are;

• Disappearance of streams and springs
• Drying up and siltation of rivers
• Vanishing wetlands (which are crucial as earlier discussed.)
• Drought

Mitigating the effects of Eucalyptus Plantations

Cut down eucalyptus trees and plant more indigenous trees in phases. Farmers have been encouraged to plant Grevillea Robusta (indigenous tree) which can be used as timber and firewood.

Areas where Eucalyptus should not be planted. Source: World Rainforest Movement 

1. Riparian areas
2. Wetlands and marshy areas
3. Irrigated farm lands.
4. Areas with less than 400mm of rainfall.
5. In farms next to water sources, planting should be minimized by inter-planting with indigenous tree species or in mosaic plantations between indigenous trees with the latter occupying a greater percentage or strip planting of eucalyptus with natural vegetation.”

We should always see where the problem arose in order for us to realize how we can move forward.

Image Credits: Go Blog.