15 billion trees in ten years? That’s nothing but hot air!


The Sunday Nation


16 July 2023


There are two questions raised regarding the government’s plan to plant 15 billion trees over the next ten years. First is whether we have the capacity to achieve this fete and second is whether we have the space to accommodate all the trees.

By the time Wangari Maathai was awarded the Nobel Prize for Peace in 2004, she had planted about 30 million trees through Green Belt Movement starting from 1977 – a period of 27 years. This comes to an average of about one million trees per year. Of course, the organisation started small and grew year by year – perhaps several thousands of trees annually in the beginning and a few million towards the end.

Still, at one million trees annually, we get 10 million trees in ten years. To plant 15 billion in 10 years, we must plant at least 1.5 billion every year. Considering that our tree-planting season for about 100 days (March, April and May), it turns out that we must plant about 15 million trees daily during the long rains….and repeat that for 10 years.

Is that possible? What would it take? I have some experience with planting trees. It takes about 25 workers to plant 5,000 in one day. That is, about 200 seedlings per person; therefore, we need about 75,000 workers to be dedicated to this exercise during the long rain season. Remember, this is also the time when farmers are busy planting food crops. Clearly, there will be a challenge in getting enough labourers for the job – even if we have money to pay them.

Let us now turn to space. Most trees are planted with spacing of about 2m-by-2m. This comes to about 4 square metres (NB; not 4-metre-squares!) for each tree. The annual target of 1.5 billion trees will, therefore, need a total of about 6 billion square metres, or 600,000 hectares (1.5 million acres) – every year. Since trees take about ten years to mature, we shall need to find this much land every year until the end of the programme. In total, we need to earmark 6 million hectares or 15 million acres.

What about money? Well, between 2007 and 2016, The African Development Bank spent close to US$40 million under its Green Zones Development Support Project to reforest 14,000 hectares. Using this costing, it turns out that we need about US$1.7 billion every year to plant the 1.5 billion trees. That is about Sh240 billion annually.

All things considered, this 15 billion trees campaign appears to be nothing but hot air!

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