I am not ‘Slay Queen’ of rivers, wetlands…

No other tree species in Kenya has precipitated such an outpouring of emotional vilification by environmental conservationists over its existence, especially those fighting to save the country’s wetlands and rivers than the eucalyptus, a native of Australia.

Special Science Correspondent Wandera Ojanji, had a chat with the tree on its good and bad times since landing on the East African soil more than a century ago…

QUESTION: Some leaders in the country have been calling on farmers to uproot you with others even declaring you “bratus-non grata” in some counties.  Why are you so demonised?

EUCALYPTUS: I migrated to this beloved country more than a century ago and since then, I have had a cordial and mutually beneficial relationship with all, until a few years ago when some people started blaming me for the drying up of water sources, rivers and springs, reducing biodiversity, increasing flooding, reducing nutrient cycling and all manner of ills.

Shockingly, even fingers are now being pointed at me, my offsprings and siblings for the food insecurity! However, most of these concerns have no scientific basis. The campaign to demonise and finish our humble community of trees is premised on environmental romanticism fuelled by fiction and speculation.

Q: One of the accusations against you is that you suck up copious amounts of water and fail to realise that it is a shared resource…How true is this?

A: Yes. But my physical size and DNA demand more water than many other of my indigenous colleagues. For instance, my hybrid kin consume approximately 2,526 litres of water annually compared to Earleaf acacia’s (Acacia auriculiformis),1,231, Albizia lebbeck (Women’s Tongue or Mkungu in Swahili),1,283, and the Indian rosewood (Dalbergia sissoo) 1,534.

This is data you can get from the Kenya Forestry Research Institute (Kefri). But this fact has been misrepresented and distorted by our enemies.

Eucalyptus tree leaves. Photo/Courtesy

Those waging a campaign to wipe us out of the face of the earth fail to appreciate the fact that fast growing trees, and not just eucalypts evapo-transpire faster than slow growers— and because we are grown for biomass, we need enough water for us to grow fast and big.

It’s a fact that we are the most efficient water users. Comparative studies on water consumption and biomass production show eucalyptus hybrids have higher water use efficiencies than other species.

For instance, for every litre of water consumed, we produce 2.06 grammes of biomass compared to only 1.83 grammes produced by Women’s Tongue’s, Dalbergia sissoo 1.31grammes, and Earleaf acacia1.39 grammes. And compared to other crops, we pale out in water consumption.

Kefri has established that while we require about 785 litres to produce one kilogramme  of  biomass, cotton, coffee and banana each require 3,200 litres and sunflower, 2,400 while maize, sorghum and potatoes require 1,000 litres each to produce same amount of biomass. These are hard scientific facts…

Q: Do you think you are being blamed for the drying up of rivers, swamps and other wetlands because of your preferential location near or on such threatened resource?

A: My colleague trees, not just eucalyptus do not drink water in the literal sense; water is our blood, our survival and we are not that stupid to engage in activities that threaten our survival and benefactors.

Along rivers we have evidence of streams flowing all the year round with giant eucalyptus trees towering over them. The decrease of water resources is even in areas where we hardly inhabit.

The curse of our water loss that has befallen our beloved country is a consequence of human activity;  the misuse and mismanagement of agricultural land and clearing of forests, especially natural forests. We, like other tree species, are innocent victims in this greed.

Q: …and your future in Kenya?

A: Very bright. I am popular among  farmers because I am fast-growing, my multiple uses, ease of establishment, wide range of adaptation and superior quality of products including timber and fibre. Ironically, the more the noise against me, the more popular I become.

There is evidence that our population is growing globally with the eucalyptus plantations doubling every decade while an increasing number of smallholder farmers are abandoning unreliable subsistence farming to embrace us as profitable enterprise.

Of course, farmers need proper advice on which variety of my kin to grow, where to grow and how to us to minimise adverse environmental footprints. I will continue to be a permanent feature in the Kenyan forestry landscape.

Let me give you figures released by the United Nations Food and Agriculture Organisation (FAO) to show our global presence; the global area under eucalypts was estimated at 700,000 hectares in 1955, rising to  four million hectares in 1979 and exceeding 10 million hectares to date.

In Kenya, we occupied less than 50,000 hectares in 2009 but increased to the current more than 100,000 hectares, making us the most popular and preferred tree species in the country. 

Elsewhere, we are rated highly; in Ethiopia, where my kin have been for more than 400 years, we occupy 250,000 ha, Angola 390,000ha, South Africa1.2 million ha, Spain 390,000 ha, Brazil4 million ha, India, 4.5 million ha and China 8.3 million ha.

In native Australia, we are 75 per cent of the tree population while globally, we account for 50 per cent. 

Q: Finally, where do you thrive best?

A: I grow well and in harmony with the environment in areas with annual rainfall above 1,200 millimetres. However, we can also survive in areas with annual rainfall ranging between 400 and 1,200 mm, but you have to pick my close kin, the clones and hybrids that are suited for such areas. And more adaptive kin are birthed at Tree Biotechnology Programme Trust.

Q.Your parting shot?

A. I beg for understanding…let not those who have failed in their obligations to nurture nature use us as an excuse for the consequences of their greed…  we are not the “Slay Queens” of rivers! 

I must emphasise that in drier climates, tree plantations frequently reduce annual water yields, especially when they replace grasslands and farmland. Large plantations of fast-growing trees often reduce stream flow during the dry season as witnessed in South Africa.

Large areas of riverside land were planted with eucalypts, black wattle and pine during the 1950s and ‘60s, and these led to a dramatic decline in the water available to users further downstream. As a result, in the mid-1990s, the South African government removed Eucalyptus and other forest plantations from water catchments and riparian areas.

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