The Faidherbia albida
There are several common name for the Faidherbia albida and the one I find most fitting is Apple-ring acacia. This name derives from the seed pods that resembles apple rings. It can grow up to 30 meters in height and it is highly resistant to drought due to its deep-penetrating tap root. It shed leaves in the rainy season. That is why it is highly valued in agroforestry as it can grow among field crops without shading them. It is a tree native to Africa and the Middle East.
A threat to the Faidherbia albida woodlands in Mana Pools
The apple-ringed seed pods from the Faidherbia albida is one of the reasons why animals thrive on the floodplains in Mana Pools. The seed-pods are relished by most animals in Mana Pools except by warthog and zebra.
The woodlands in Mana Pools will change if action isn’t taken.
The problem is the lack of regrowth of albida trees on the floodplain. Before the dam at Lake Kariba was constructed, there were an annual flooding of the Zambezi. Their seeds, like many others, stay in a condition called seed dormancy. It is a survival mechanism which ensures that germination only occur during good conditions. These conditions for the albida seed normally require flooding.
The albida seed have a hard seed coat, which hamper seed germination. A flooding not only add water, but also the possibility to break the seed coat required for germination. Water soften the seed coat and the flowing water make it possible to scar the seed coat, for instance by hitting the seed against a stone.
What will the future hold?
What can be done to start the regrowth of trees on the floodplain?
The most natural way would be if they could manage a regulated flooding of the Zambezi. Sadly I don’t think that will be possible as Lake Kariba acts as power supply for two countries. Then, you have all the people living by the Zambezi so it isn’t an easy equation to solve. Still I think that over time it might be the most cost-effective and least harmful way.
The only other option I see is to pretreat albida seeds before the rain period and when the rain starts release the seeds with hope of successful germination. That way will be a hit or miss. You could easily turn the ecology upside down due to more seeds germinating than during a natural flooding. It needs to be tested thoroughly before applied as the impact could be severe.
Lets hope they can find a viable solution to preserve the ecology in Mana Pools for the future.