Orphan Trees (Principles)
Forest regeneration, remnant trees, seed dispersal, slash-and-burn agriculture, succession, tropical forest
To encourage a quick and diversified regeneration of their forest after they leave a slash-and-burn field, the semi-nomadic Ntumu folk of the south Cameron have developed a knowledge and a practice, the so-called "forest orphans trees". The orphan tree technique consists of the selective falling of trees for their agriculture needs. They systematically keep certain trees (about 15 trees per hectare) having a high cultural, agronomical or ecological value.
Those trees might provide food sources (fruits and seeds) medicinal products, provide fuel or construction material or host specific animals.
Some species like the cheese tree are particulary valuable for their role in the soil fertility. other such trees are the Ceiba pentandra, Triplochiton scleroxylon and Terminalia superba and represent one-third of the protected trees.
Those trees will then play a very important role in the regeneration of the forest when the nomads move to another part of the forest. They become a good shelter and food source for seed dispersing birds and animals. Observations shows that hundred different sorts of seeds are found under those trees, much more than in the open fields. Those seeds are for a bigger part treeseeds. On the contrary, seeds found in the open field are shortlive plants. Orphan trees also create a microclimate, shadow and humidity, favourable for young plants and trees. The forest starts regenerating from thoses trees and while its bioversity does not impoverish, the number of useful species slowly increases.
Stephanie Carriere of the IRD studied the practice of the Ntumu for two years in the frame of the APFT program (Avenir des Peuples des Forêts Tropicales)
- S. M. Carrière "L'abattage sélectif : une pratique ancestrale au service de la régénration forestière", Bois et forêts des tropiques, n° 272, 2002.
- S. M. Carrière, "Orphan trees of the forest : why do Ntumu farmers of
Southern Cameroon protect trees in their swidden fields", Journal of Ethnobiology, summer 2002.
- S. M. Carrière "Effects of remnant trees in fallows on diversity and structure
of forest regrowth in a slash-and-burn agricultural system in Southern Cameroon" Journal of Tropical Ecology, 2002.
- S. M. Carrière "Seed rain beneath remnant trees in a slash-and-burn
agricultural system in southern Cameroon". Journal of Tropical Ecology, 2002.
Stéphanie Carrière, UR 100 " Transitions agraires et dynamiques écologiques", Centre IRD Ile-de-France,32 rue Henri Varagnat, 93143 Bondy, France http://www.bondy.ird.fr/~carriere/