Iroko
trees are native to the west coast of
Africa. Sometimes called Nigerian teak, their wood is tough, dense,
and very durable. Their hardwood is so sought after that the trees are often
poached and are now endangered in many regions of Africa. But a new scientific
discovery may aid in reforestation efforts.
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Oliver
de Schutter, the United Nations special rapporteur on the right to food, has
found that Iroko trees can serve as long-term carbon sinks and
can potentially play a role in the fight against climate change. Iroko trees
and microbes can turn carbon dioxide emissions into soil-enriching limestone, a
process that packs a one-two punch: carbon dioxide is removed from the
atmosphere, and dry, acidic soil is made more fertile for agriculture.
When
the West African Iroko tree is grown in dry, acidic soil and treated with
microbes, it produces a very specific mineral. When the microbes are
introduced, the tree combines the calcium already in the soil and carbon
dioxide from the atmosphere to produce a mineral limestone. This mineral
limestone is then stored in the soil around the Iroko tree’s roots.
Normally,
biomass (such as trees) does not store carbon dioxide—the gas is used in the
process of decomposition. But carbon in
the form of limestone has a staying time that may span a million years.
This makes a great case, according to Swiss researchers, for the preservation
and sustainable management of tropical forests to fight against the greenhouse
effect.
Iroko
trees are just one of many species from Africa and the Amazon that can turn
carbon in the atmosphere into mineral limestone. In this study, scientists
looked at several microbe-tree combinations to identify which was best for
locking up carbon dioxide as limestone, and the Iroko-microbe pathway showed
the greatest results.
“By
taking advantage of this natural limestone-producing process, we have a
low-tech, safe, readily employed and easily maintained way to lock carbon out
of the atmosphere, while enriching farming conditions in tropical countries,”
said Dr Bryne Ngwenya
of the University of Edinburgh’s School of GeoSciences.
There
is also great potential for reforestation projects to help reduce carbon
dioxide emissions in the developing world. Reforestation schemes that involve
the use of microbes and Iroko trees together could improve the carbon
sequestration balance of carbon trading initiatives, improve soil fertility,
and even promote the implementation of agroforestry projects to benefit rural
communities.
See more
at ENN affiliate WorldWatch
Institute.
Iroko tree via google
images.