Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The prolific orphan trees in the Cameroon forests

29.04.2003


The Ntumu (the Beti-Fang), live in the equatorial forest in southern Cameroon, in the north of Gabon and of Equatorial Guinea. They practice a semi-nomadic slash-and-burn form of agriculture. Their farming is highly diversified, mainly of food crops (such as cassava, plantain banana, sweet potato, yam and taro) but they also produce cash crops (cacao, groundnuts). When they clear a plot (1 ha on average), the Ntumu systematically spare certain trees, generally about 15 whatever cutting methods or implements they use: chainsaw or axe. Thus, contrary to what is often stated, selective felling is conducted not because the workforce is insufficient or for lack of time. Nor is determined by the hardness of the timber or the exhausting nature of the task. On the contrary, it is a deliberate traditional practice which requires a sophisticated knowledge of the environment and the different types of forest trees. It demands a long learning period.



Why do the Ntumu spare these trees, “orphans of the forest”, as they call them? Investigation of the species preserved reveals that they have a high social, cultural, agronomic and even ecological value in the long term. They are varieties that can provide food or medicinal resources (fruit and seeds), firewood or construction timber or represent prized hunting grounds. Some species, such as the kapok tree also contribute to the habitat’s fertility; their presence improves food production thanks to the humus generated by falling leaves, flowers and fruit as well as the shade they offer for crops. The three species – Ceiba pentandia, Triplochiton scleroxylon and Terminalia superba – which most particularly play this fertilizing role have a high cultural value and hence together represent a third of all protected trees left in the fields.

The orphan trees have, other than their immediate utility in the Ntumu’s subsistence economy, a driving role in forest regeneration when the fields return to fallow. These trees constitute highly attractive sites for seed-dispersing animals (birds, bats, monkeys) which use them to perch or as shelter against predators and sometimes find abundant food in them. In addition, under their crown, the seed density and diversity (over 100 different species1 have been recorded) are clearly higher than for those observed where no such trees remain. Most of these seeds belong to ligneous species (97% as against 60% in open fields)2. The trees isolated in the fields also create a microclimate which favours, or even accelerates, regrowth of forest species. They supply an input of nutrients (leaves, fruit, animal excreta) and increased soil humidity thanks to the shade under the crown. This shade encourages long-life forest tree species. In contrast, in some areas of the open plots, more short-life heliophile pioneer species are found. These species, most often herbaceous, are sometimes invasive. Forest regrowth thus develops more rapidly and intensively under the orphan trees: they act as the nuclei of regeneration which, when they coalesce will contribute to the rapid reconstitution of the forest cover.


At the level of agricultural regime, this ancestral practice favours the maintenance of a forest cover and contributes to the continuation of slash-and-burn agricultural systems. At the landscape level, the farmers have over the centuries, by systematically selecting certain species as they clear forest, oriented the specific diversity of the Cameroon forest towards a greater proportion of useful species, which can become highly valued. This long-term strategy of forest management thus represents one of the many agricultural approaches in which environmental factors are taken into account that forest-dwelling peoples in the tropics have developed.

Marie-Lise Sabrie | alfa
Further information:
http://www.ird.fr

More articles from Ecology, The Environment and Conservation:

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

nachricht A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>