Forests Of Central Africa Research Articles

Dynamics of montane forest in central Africa during the late Holocene: a pollen-based record from western Uganda

According to the results from a number of palaeoecology-based studies, montane forest appears to have been present across a broad range of altitudes in western Uganda throughout much of the Holocene (before increased levels of human impact over the past 2000 years or so resulted in extensive clearance). Critically for pollen-based studies of vegetation history, clearance has limited investigations into the late-Holocene history of montane forest, and thus the impact of small amplitude, sub-Milankovich variations in climate and low levels of human activity. Mubwindi Swamp in the Rukiga Highlands of southwest Uganda is today surrounded by dense stands of moist lower montane forest. The uppermost 5 m of organic-rich deposits from Mubwindi Swamp are dated to the last 2100 years, and thus provide an opportunity, so far unique for Uganda, to record variations in the composition of lower montane forest during the late Holocene. Results of analyses of pollen indicate that lower montane forest has been present in the catchment for Mubwindi Swamp throughout the last 2100 years. A transition to a more open, and possibly drier, form of forest is apparent from around 710 BP. It seems likely that this transition was at least partly driven by climate. There is an increased occurrence of pollen from plants presently associated with areas of degraded forest from around 200 BP and a decrease in pollen from important sources of timber. These changes could be interpreted as representing slightly increased humidity. However, in view of the nature of these changes, a low level of human impact was probably the most important causal factor. The gazetting of Bwindi-Impenetrable Forest as a Forest Reserve in the early 1930s may have facilitated a recovery of timber trees during the present century.

Soils of the lowland forests of West and Central Africa

The forest zone of West and Central Africa comprises the coastal and adjacent inland regions bounded the semi-deciduous forests in the west and the equatorial forests in central Africa and the Congo basin. Sedimentary plains, developed mostly on weathered sandy materials, lie along the coastal stretches and cover vast areas of the Congo basin. Behind the coast the plain rises gradually to hills and plateaus of much lower elevation than those of the highlands of East Africa. Two great rivers, the Niger and the Congo, which discharge huge volumes of fresh water to the Atlantic Ocean, are major contributors to the hydrological cycles of the rain forests ecosystems of the Guinea–Congo Region. The Niger originates from the forested highlands of Guinea and discharges its waters into the Bight of Benin by way of a large delta in southern Nigeria. The Congo basin occupies an immense area of 750 000 km2, surrounded by Pre-Cambrian uplands. The alluvial floor of the saucer-shaped basin is flat, and marshes and swamps comprise a large proportion of the total area. The highlands and plateaus along the rim are low to the west and north and higher to the south. To the east, they merge with the mountains of the Great Rift Valley of East Africa (Gann & Duignan 1972; Hance 1975; Grove 1978; Hamilton 1989).

Emissions of nitrogen oxides from equatorial rain forest in central Africa:. origin and regulation of NO emission from soils

Emissions of nitrogen oxides from equatorial rain forest in central Africa:. origin and regulation of NO emission from soils

Emissions of nitrogen oxides from equatorial rain forest in central Africa: origin and regulation of NO emission from soils

Emissions of nitric oxide from soils of equatorial rain forest were measured in the Dimonika Natural Park (4°30′S, 12°30′E) in the Mayombe Forest in Congo. Three research campaigns were carried out in June and July 1991 and in February 1992. Fluxes were measured by dynamic chamber techniques using a chemiluminescence instrument Scintrex LMA3. NO fluxes measured on natural soils are in between 5 and 17 × 10 9 molecules cm -2 s -1 ; they are of the same order of magnitude as those observed in similar tropical forest media. Soil treatment experiments show that the auto-decomposition of HNO 2 in these acid soils (pH# 4) (chemodenitrification) is a potentially important cause of nitric oxide production in this type of ecosystem. Nitrous acid comes from autotrophic nitrification all the year round, and also from biological denitrification, shown by N 2 0 emissions, during the rainy season. The regulation of NO release from soils is linked to ammonia production from litter mineralisation and to direct NH 4 input by throughfall. DOI: 10.1034/j.1600-0889.1994.t01-3-00001.x

Methane emission from flooded forest in central Africa

In this report we give results of methane flux measurement in the flooded forest zone of the Congo River basin in central Africa. Methane fluxes are measured by the static chamber method above three types of soils characterized by various water contents. High methane emission is recorded on flooded soils (4.59 × 1012 molecules/cm2/s) while methane uptake occurs in dry soil (−8.38 × 1010 molecules/cm2/s). Methane flux is also derived from variations of surface concentrations of methane related to the variations of air stability and from vertical profiles in the lower troposphere. The four methods used to determine the average methane emission from this wetland type yield compatible values. The average yearly flux is estimated at 2 to 4 × 1012 molecules/cm2/s or 45 to 90 mg/m2/d The total wetland area being about 105 km2, global methane emission from the flooded forest zone of the Congo River basin would represent 1.6 to 3.2 Tg (CH4) per year.

Occurrence of Glossina nashi Potts 1955 Diptera-Glossinidae in the Republic of Gabon.

Glossina nashi, a little known species of tsetse fly, inhabits the forests of central Africa. It has recently been detected in the Province of Haut Ogooué in the south-east of the Republic of Gabon.

A propos des thérapeutes Pygmées Aka de la région de la Lobaye (Centrafrique)

Within the study on the therapeutist role among the Aka pygmies of the Lobaye rain forest in Central Africa, the author takes more particular interest in soothsayers-healers «bondo», in their initiation, in the part they play in different rituals and in the plants they use on these various occasions.

A forest in the city

most fitting motto for anthropology must surely be, The more you see others the better you see yourself. Anthropologist Colin Turbull provides a close look at the Pygmies the Ituri Rain Forest in Central Africa in his book, Forest People.l book tells not only their adaptations to the forest environment, but also the relationship between the Pygmies and the nearby Negroes. Negroes live in farming villages while the Pygmies are huntergatherers with no permanent settlements and, although the two groups associate with one another (each for their own reasons), the differences in outlook and lifestyle allow only a minimum mutual respect and understanding. As I read, I could see that in some ways their relationship mirrored experiences I have had as a teacher in an inner-city school. I began to see myself in the role Negro villager in the settled community the school and to see my students as Pygmies and the streets as their forest. Naturally this comparison may raise some eyebrows, as the physical properties the analogy may be taken as important when they are not. I do not offer this comparison because any us in the analogy are black; nor do I case students in the role Pygmies because their stature. comparison stems from the fact that, in the midst the students' environment, I represent a different way life with a different system values. And, like the Pygmies visiting the village, the students at school temporarily stay and conform to the rituals so long as it suits their ends. Like the Villagers, I and my fellow teachers consider our way superior, yet our rituals and our values survive only through constant struggle even within our own compounds-and beyond our artificial environments other forces assume control. I have known the tribes several neighborhoods but, aside from minor variations in style or dialect, the relationship has been the same for, like the Pygmies who are of the forest, they are of the street.

Les contraintes écologiques en forêt tropicale humide: l'exemple des Pygmées Aka de la Lobaye (Centrafrique)

On the basis of ethnobiological field work among the Aka Pygmies of the Lobaye rain forest in Central Africa, the author considers the problem of ecological constraints in the case of the societies living in the tropical rain forest.