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See detailHigh spatial resolution of late-Holocene human activities in the moist forests of central Africa using soil charcoal and charred botanical remains
Morin, Julie ULg; Biwolé, Achille; Gorel, Anaïs ULg et al

in Holocene (in press)

Palaeoecological and archaeological studies have demonstrated that human populations have long inhabited the moist forests of central Africa. However, spatial and temporal patterns of human activities ... [more ▼]

Palaeoecological and archaeological studies have demonstrated that human populations have long inhabited the moist forests of central Africa. However, spatial and temporal patterns of human activities have hardly been investigated with satisfactory accuracy. In this study, we propose to characterize past human activities at local scale by using a systematic quantitative and qualitative methodology based on soil charcoal and charred botanical remains. A total of 88 equidistant test-pits were excavated along six transects in two contrasting forest types in southern Cameroon. Charred botanical remains were collected by water-sieving and sorted by type (wood charcoals, oil palm endocarps, and unidentified seeds). A total of 50 Accelerator Mass Spectrometry 14C dates were also obtained. Results showed that charred macroremains were found at multiple places in the forest, suggesting scattered human activities, which were distributed into two main periods (Phase A: 2300-1300 BP – Phase B: 580 BP to the present). Charred botanical remains indicated two types of land use: (i) domestic, with oil palm endocarps most often associated with potsherds (villages) and (ii) agricultural, with charcoal as probable remnant of slash-and-burn cultivation (fields). Oil palm endocarp abundance decreased with distance from the identified human settlements. Our methodology allowed documenting, at high resolution, the spatial and temporal patterns of human activities in central African moist forests and could be applied to other tropical contexts. [less ▲]

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See detailThe last 1,000 years in the Northern Congo Basin
Morin, Julie ULg; Fayolle, Adeline ULg; Favier, Charly et al

Conference (2015, November)

Review of the events that happened in the northern Congo basin during the last 1,000 yr. Positive impact of human disturbances on the regeneration of light-demanding trees. Negative impact of the European ... [more ▼]

Review of the events that happened in the northern Congo basin during the last 1,000 yr. Positive impact of human disturbances on the regeneration of light-demanding trees. Negative impact of the European colonization and following events on human populations and tree regeneration. [less ▲]

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See detailThe Tervuren xylarium and wood biology to decode the ecological memory of forests and trees
Morin, Julie ULg; Bourland, Nils; De Ridder, Maaike et al

Conference (2015, October 15)

Presentation of the competences held by the Wood Biology Service members of the Royal Museum for Central Africa, relative to their potential uses in archaeology.

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See detailSeeing Central African forests through their largest trees
Bastin, Jean-François ULg; Barbier, Nicolas; Réjou-Méchain, Maxime et al

in Scientific Reports (2015)

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which ... [more ▼]

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies. [less ▲]

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See detailLate-Holocene tropical moist-forests of southeastern Cameroon: some insight from soil charcoal analysis
Morin, Julie ULg; Biwolé, Achille; Bourland, Nils et al

Conference (2015, August)

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. Little is known, however, about past vegetation in this region that remains underexplored ... [more ▼]

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. Little is known, however, about past vegetation in this region that remains underexplored (Vleminckx et al. 2014; Morin-Rivat et al. 2014). Determining the past specific composition of these forests could allow bringing insights into their evolution over time and providing data about their resilience capacity facing global change. We performed a pedoanthracological analysis in the semi-deciduous forests of southeastern Cameroon. We excavated 53 test pits of 53 50 × 50 × 60 cm in plots of botanical inventory along a NS 80-km long mega-transect that followed a vegetation gradient. We sorted and quantified charred macrobotanical remains by layers of 10 cm, then identified species from wood charcoals. We used the InsideWood database, implemented with 163 new anatomical descriptions of woods present in the study area by using the reference collection of African woods of the Royal Museum for Central Africa (Belgium). Finally, we obtained 25 radiocarbon dates on charcoals and oil palm endocarps. Results showed that repeated fire events occurred across the study area during the last 2500 years, soon after the well-documented “rainforest crisis” (e.g. Lézine et al. 2013). The analyzed charcoals are likely human-induced regarding evidence of associated human settlements (e.g. potsherds). Aged were distributed into two time periods: the Early Iron Age (2300-1300 BP) and the Late Iron Age (700-100 BP) with an intermediate hiatus in human occupation (see e.g. Wotzka 2006; Morin-Rivat et al. 2014). Specific composition during both periods did not strongly differ from current composition, which is now dominated by light-demanding canopy trees belonging to old-growth semi-deciduous Celtis forests (Gond et al. 2013; Fayolle et al. 2014). This argues in favor of the maintenance of light-demanding tree species by anthropogenic activities, such as slash-and-burn shifting cultivation. We conclude that moist forests have a good resilience capacity regarding moderate and scattered disturbances. These forests can nonetheless be deeply impacted by land-use intensification (e.g. degraded forests along roads and close to cities; Gond et al. 2013). [less ▲]

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See detailContributing to wood anatomical databases to improve species identification, phylogeny and functional trait research in Central Africa
Morin, Julie ULg; Fayolle, Adeline ULg; De Ridder, Maaike et al

Poster (2015, May 26)

Central African rainforests shelter a high number of woody species that are anatomically very different. Knowledge of taxon-specific wood anatomical features has proven indispensable for scientific and ... [more ▼]

Central African rainforests shelter a high number of woody species that are anatomically very different. Knowledge of taxon-specific wood anatomical features has proven indispensable for scientific and non-scientific applications. The field of wood anatomy and identification has been drastically revolutionized by the development of internationally recognized lists of precisely illustrated microscopic features (e.g. IAWA Committee 1989), together with the launch of InsideWood, an online search database using these features to narrow down identification results (e.g. Wheeler 2011). However, despite these massive efforts, the anatomy of many species or even genera remains in the dark, especially in species-rich regions. Wood anatomy has been formally described for less than 25% of the Central African woody species (Hubau et al. 2012), the focus has been mainly on timber species and variations in wood anatomical structure remain to be explored. Therefore, we are assembling a wood anatomical database of about 800 species covering the Guineo-Congolian region using material from InsideWood and the Tervuren xylarium (new descriptions). As such, we present how large anatomical databases hold interesting perspectives for (i) wood and charcoal identification, (ii) exploring the phylogenetic signal of wood anatomy, and (iii) the relationship between wood anatomical features and functional traits. [less ▲]

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See detailAnatomic features underlying wood density, in 110 rainforest tree species from central Congo basin
de Haulleville, Thalès ULg; Rousseau, Mélissa; Morin-Rivat, Julie ULg et al

Poster (2015, May)

Investigate the influence of fiber thickness and vessel diameter on the wood density in 110 rainforest tree species, and the relationships between wood density, wood water content and shrinking ratio.

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See detailHigh spatial resolution of late-Holocene human activities in the moist forests of Central Africa using soil charcoal and charred botanical remains
Morin, Julie ULg; Biwolé, Achille; Gorel, Anaïs ULg et al

Conference (2015, April 27)

Palaeoecological and archaeological studies have demonstrated that human populations have long inhabited the moist forests of central Africa. However, spatial and temporal patterns of human activities ... [more ▼]

Palaeoecological and archaeological studies have demonstrated that human populations have long inhabited the moist forests of central Africa. However, spatial and temporal patterns of human activities have hardly been investigated with satisfactory accuracy. In this study, we propose to characterize past human activities at local scale by using a systematic quantitative and qualitative methodology based on soil charcoal and charred botanical remains. A total of 88 equidistant test-pits were excavated along six transects in two contrasting forest types in southern Cameroon. Charred botanical remains were collected by water-sieving and sorted by type (wood charcoals, oil palm endocarps, and unidentified seeds). A total of 50 Accelerator Mass Spectrometry 14C dates were also obtained. Results showed that charred macroremains were found at multiple places in the forest, suggesting scattered human activities, which were distributed into two main periods (Phase A: 2300-1300 BP – Phase B: 580 BP to the present). Charred botanical remains indicated two types of land use: (i) domestic, with oil palm endocarps most often associated with potsherds (villages) and (ii) agricultural, with charcoal as probable remnant of slash-and-burn cultivation (fields). Oil palm endocarp abundance decreased with distance from the identified human settlements. Our methodology allowed documenting, at high resolution, the spatial and temporal patterns of human activities in central African moist forests and could be applied to other tropical contexts. [less ▲]

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See detailA novel procedure to measure shrinkage-free tree-rings from very large wood samples combining photogrammetry, high-resolution image processing, and GIS tools
Latte, Nicolas ULg; Beeckman, Hans; Bauwens, Sébastien ULg et al

in Dendrochronologia (2015), 34

We present a new procedure for wood sampling and tree-ring measurement that can be used for dendrochronological investigation on very large trees, specifically adapted for tropical rainforest species ... [more ▼]

We present a new procedure for wood sampling and tree-ring measurement that can be used for dendrochronological investigation on very large trees, specifically adapted for tropical rainforest species. This procedure takes advantage of the technological developments in computing, image processing, and geographic information systems (GIS) to overcome the technical limitations of the currently used methods. Two types of wood samples can be used (stem disks and/or bars) depending on tree diameter, and the difficulty of ring delineation and crossdating. Bars are an effective compromise between cores and disks. We developed an application combining several programs (Excel, R, ArcGIS, and MapWinGIS) in the Windows operating system for semi-automatic measurement of tree-rings from high-resolution images of the sanded cross-section. Using an innovative method to reverse the wood shrinkage resulting from the drying process, tree-ring measurement can be performed on shrinkage-free images, thus referring to the actual growth of the tree. [less ▲]

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See detailNineteenth century human history explains the dominance of light-demanding tree species in Central African moist forests
Morin, Julie ULg; Fayolle, Adeline ULg; Favier, Charly et al

Poster (2015, March 21)

The canopy of central African moist forests is dominated by light-demanding trees. Most of these species show a distribution of diameters that indicates a regeneration shortage. Here we show through the ... [more ▼]

The canopy of central African moist forests is dominated by light-demanding trees. Most of these species show a distribution of diameters that indicates a regeneration shortage. Here we show through the combined analysis of botanical, palaeoecological, archaeological and historical data that most of these trees are not older than ca. 180 years. This age corresponds to the early 19th century (around 1830) when the slave-raiding, the interethnic wars and the colonization of the inlands by the Europeans disturbed the human spatial occupancy. After 1885, the spatial clumping of people and villages along the main communication axes induced less itinerancy in the forest. We believe that former activities such as shifting cultivation created scattered openings in the canopy, large enough to allow light-demanding trees to establish. Nowadays, common logging operations do not create openings sufficiently large for the regeneration of these high value timber species. Our findings emphasize the need to include considerations about the history of human spatial occupancy and activities to understand forest dynamics. We need silvicultural guidelines adapted to the autecology of the species. Population enforcements (e.g. enrichment) will be needed to ensure the sustainability of timber yields in forests dominated by long-lived light-demanding trees. [less ▲]

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See detailIdentification of charred botanical remains provides more accurate information on past history in Central Africa
Morin, Julie ULg; Biwolé, Achille; Bourland, Nils et al

Poster (2015, January 30)

In palaeoenvironmental studies, charred botanical remains have rarely been identified to the species level before being sent to radiocarbon dating. Moreover, the age of most tropical spp. and thereby the ... [more ▼]

In palaeoenvironmental studies, charred botanical remains have rarely been identified to the species level before being sent to radiocarbon dating. Moreover, the age of most tropical spp. and thereby the age of the carbon sequestered during plant growth is not known. Dating unidentified charred wood in the tropics should be thus treated with caution because the accuracy of the dates is not guaranteed. Here we present 71 dates obtained on charred endocarps and wood charcoals sampled in soil pits in Cameroon and in the Rep. of the Congo. We taxonomically identified 43 samples then selected both identified and unidentified individual fragments for radiocarbon dating. We performed summed probability distributions of the dates calibrated in BP for the 43 identified and the 28 unidentified samples separately then for the whole dates. Results showed that the dates obtained on unidentified samples better fit the established chronology for Central Africa but that they also presented less precise standard deviations than the dates obtained on identified short-lived material, and that the dates on identified samples provide more detailed trends about the phases of human occupation in Central Africa after 2,500 BP. We can assume that dating unidentified material may introduce some blur into chronologies and that the selection of identified charred botanical remains should be systematically applied for palaeoenvironmental reconstructions in tropical contexts to refine the chronologies. [less ▲]

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See detailHow Tightly Linked Are Pericopsis elata (Fabaceae) Patches to Anthropogenic Disturbances in Southeastern Cameroon?
Bourland, Nils; Cerisier, François; Daïnou, Kasso ULg et al

in Forests (2015), 6(2), 293-310

While most past studies have emphasized the relationships between specific forest stands and edaphic factors, recent observations in Central African moist forests suggested that an increase of slash-and ... [more ▼]

While most past studies have emphasized the relationships between specific forest stands and edaphic factors, recent observations in Central African moist forests suggested that an increase of slash-and-burn agriculture since 3000–2000 BP (Before Present) could be the main driver of the persistence of light-demanding tree species. In order to examine anthropogenic factors in the persistence of such populations, our study focused on Pericopsis elata, an endangered clustered timber species. We used a multidisciplinary approach comprised of botanical, anthracological and archaeobotanical investigations to compare P. elata patches with surrounding stands of mixed forest vegetation (“out-zones”). Charcoal samples were found in both zones, but were significantly more abundant in the soils of patches. Eleven groups of taxa were identified from the charcoals, most of them also present in the current vegetation. Potsherds were detected only inside P. elata patches and at different soil depths, suggesting a long human presence from at least 2150 to 195 BP, as revealed by our charcoal radiocarbon dating. We conclude that current P. elata patches most likely result from shifting cultivation that occurred ca. two centuries ago. The implications of our findings for the dynamics and management of light-demanding tree species are discussed. [less ▲]

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See detailWood anatomical characteristics of 600 African tropical species in relationship with their ecology
Morin, Julie ULg; Fayolle, Adeline ULg; Doucet, Jean-Louis ULg et al

Poster (2014, December 16)

The tropical moist forest is a biome with a high number of species that are functionally different. The question arises whether there are patterns in the spectra of wood anatomical features according to ... [more ▼]

The tropical moist forest is a biome with a high number of species that are functionally different. The question arises whether there are patterns in the spectra of wood anatomical features according to functional types. Here we propose to present the main anatomical characteristics of 600 tropical species from the Guineo-Congolian domain in relationship with their ecology. We cross-checked two databases: the anatomical database InsideWood and the CoForTraits database of functional traits produced during the CoForChange project. After characterizing the main trends of the dataset, we performed multivariate analyses between the wood traits (i.e. the anatomical features) and six groups of functional traits: leaf phenology, regeneration guild, dispersal syndrome, life form, plant maximum height, and wood specific gravity. Results showed (i) that several wood features were specific to the tropics, to Africa or only to the Guineo-Congolian region, and (ii) that phylogeny explained the main part of the variation among the traits, whereas (iii) wood structure provided nonetheless interesting functional information related to gradients in plant growth, survival, and dispersal, and (iv) that there was a functional convergence in the study species in response to similar environmental constraints. These observations suggest that certain anatomical features can be used as indicators of functional traits in species-rich biomes. Further research will enable us to increase the input of wood anatomy in explaining the functional trade-offs in African tropical species. [less ▲]

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See detailLate-Holocene moist forests of Central Africa: contribution of charcoal analysis
Morin, Julie ULg; Bremond, Laurent; Gillet, Jean-François et al

Poster (2014, December)

Wood charcoals are often uncovered in the soils of the tropical regions. They remain little studied, however, and this observation is even truer for charcoals coming from the dense humid forests of ... [more ▼]

Wood charcoals are often uncovered in the soils of the tropical regions. They remain little studied, however, and this observation is even truer for charcoals coming from the dense humid forests of Central Africa. Here we aim at showing the interest of the analysis of soil charcoals in this region so as to understand the dynamics of past forest environments during the late-Holocene. Several examples of taxonomical identifications conducted on charcoals sampled in soil pits in Cameroon and in the Republic of the Congo are presented along with radiocarbon dates. These charcoals were hand-split then observed under an incident light microscope. The wood anatomical features that were preserved in charcoals and described according to a standard method were compared to a reference collection of woods. Results demonstrated that past burnings that spanned from 2,500 BP to Recent were human-induced and scattered in the study area. The identified species are still present in the environment today and localized changes in the vegetation occurred over the past two millennia. Charcoal analysis can thus allow a better understanding of the past history of the tropical forests in relationship with the ancient anthropogenic disturbances. [less ▲]

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See detailAnalyse à haute résolution spatiale et temporelle des activités humaines à l’Holocène récent dans les forêts humides d’Afrique Centrale
Morin, Julie ULg; Gorel, Anaïs ULg; Biwolé, Achille et al

Poster (2014, November)

Des études paléoécologiques et archéologiques ont démontré que les populations humaines ont de longue date investi les forêts humides d’Afrique Centrale. Les occupations humaines ont toutefois été peu ... [more ▼]

Des études paléoécologiques et archéologiques ont démontré que les populations humaines ont de longue date investi les forêts humides d’Afrique Centrale. Les occupations humaines ont toutefois été peu documentées en raison de difficultés relatives à l’accès au terrain. Nous présentons ici une méthodologie systématique basée sur la quantification et la datation des macrorestes botaniques carbonisés pour définir les activités humaines passées en forêt tropicale africaine. Pour cela, 53 sondages équidistants ont été creusés dans 3 sites du sud-est-du Cameroun. Dans chaque sondage ont été prélevées des quantités fixes de sol par couche de 10 cm. Les macrorestes botaniques carbonisés ont été récoltés par tamisage à l’eau directement sur le site. Les refus de tamis ont été triés (charbons de bois, endocarpes de palmier à huile, graines non identifiées), pesés sur une balance de précision et analysés statistiquement. En outre, 25 échantillons ont été datés par AMS. Les résultats montrent que les activités humaines sont réparties en deux périodes : l’âge du Fer ancien entre 2300 et 1300 BP et l’âge du Fer récent entre 670 BP et l’actuel. En outre, les charbons de bois et les endocarpes de palmier à huile ne représentent pas le même type d’activités. Deux villages âge du Fer ancien datés d’environ 2000 BP ont été identifiés par la présence concomitante d’endocarpes de palmier à huile et de tessons céramiques. Les motifs circulaires imprimés dans la céramique et inédits pour la zone d’étude rappellent les gravures et décors céramiques découverts au Gabon et dans la zone de la Sangha-Likwala-aux-Herbes, datés également de 2000 BP. L’abondance décroissante des charbons dans l’orbe d’influence de ces villages pourrait correspondre à d’anciennes zones agricoles. Les perturbations les plus récentes peuvent, quant à elles, être mises en relation avec la végétation actuelle, en particulier les arbres émergents héliophiles qui dominent la composition floristique et qui sont des recrus post-culturaux. Pour la première fois, une méthodologie quantitative basée sur les restes archéobotaniques a été appliquée en Afrique Centrale. Elle nous a permis de documenter à haute résolution la répartition spatiale et temporelle des activités humaines à l’échelle locale. Ce travail sera poursuivi par une reconstitution paléoenvironnementale à partir de l’identification des macrorestes végétaux. [less ▲]

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See detailKnowing the past to anticipate the future: soil charcoal as a proxy to model forest evolution
Morin, Julie ULg; Biwolé, Achille; Bourland, Nils et al

Poster (2014, October)

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. However little is known about their past evolution. Indeed, determining the past specific ... [more ▼]

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. However little is known about their past evolution. Indeed, determining the past specific composition of these forests could allow modeling their evolution over time and providing data about their resilience capacity facing global change. To do this, we performed a pedoanthracological analysis in the semi-deciduous forests of southeastern Cameroon. We excavated test pits in 53 plots of botanical inventory along a gradient of vegetation, quantified wood charcoals by layers of 10 cm, identify the species present in charcoals, dated the charcoals by the radiocarbon method, then built up sequences including present forest composition. Results show that repeated fire events occurred across the study area during the last 2500 years. These disturbances are likely human-induced regarding evidence of anthropogenic activities (e.g. potsherds). Nonetheless the past specific composition does not strongly differ from the current one except for the oldest layers related to the major dry climatic event of 2500 BP. We conclude that moist forests have a good resilience capacity regarding moderate disturbances but were and will be deeply impacted by climate change. [less ▲]

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See detailDensity variations and their influence on carbon stocks: case-study on two Biosphere Reserves in the Democratic Republic of Congo
De Ridder, Maaike; de Haulleville, Thalès ULg; Kearsley, Elizabeth et al

Poster (2014, April 28)

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is ... [more ▼]

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is given to this variable in terms of exact, measured values and density profiles from pith to bark. Most published case-studies obtain density values from literature sources or databases, this way using large ranges of density values and possible causing significant errors in carbon stock estimates. The use of one single fixed value for density is also not recommended if carbon stock increments are estimated. Therefore, our objective is to measure and analyze a large number of tree species occurring in two Biosphere Reserves (Luki and Yangambi). Nevertheless, the diversity of tree species in these tropical forests is too high to perform this kind of detailed analysis on all tree species (> 200/ha). Therefore, we focus on the most frequently encountered tree species with high abundance (trees/ha) and dominance (basal area/ha) for this study. Increment cores were scanned with a helical X-ray protocol to obtain density profiles from pith to bark. This way, we aim at dividing the tree species with a distinct type of density profile into separate groups. If, e.g., slopes in density values from pith to bark remain stable over larger samples of one tree species, this slope could also be used to correct for errors in carbon (increment) estimates, caused by density values from simplified density measurements or density values from literature. In summary, this is most likely the first study in the Congo Basin that focuses on density patterns in order to check their influence on carbon stocks and differences in carbon stocking based on species composition (density profiles ∼ temperament of tree species). [less ▲]

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See detailCharcoal records reveal past occurrences of perturbations in the forests of the Kisangani region(RDC): vegetation history of the semi-deciduous rainforest
Tshibamba Mukendi, John; Hubau, Wannes; Morin-Rivat, Julie ULg et al

Poster (2014, April 28)

Introduction. Past disturbances have modified the structure and the floristic composition of Central African rainforests. These perturbations represent a driving force for forest dynamics and they are ... [more ▼]

Introduction. Past disturbances have modified the structure and the floristic composition of Central African rainforests. These perturbations represent a driving force for forest dynamics and they are presumably at the origin of present-day forest mosaics. Fire is a prominent forest disturbance, leaving behind charcoal as a witness of past forest dynamics. The question arises whether quantification, dating and botanical identification of ancient charcoal fragments found in soil layers (pedoanthracology) allows a detailed reconstruction of forest history, including the possible occurrence of past disturbances. Material & methods. We organized pedoanthracological excavations in 6 regrowth sites and 48 sites of primary forests of Yangambi, Yoko, Masako and Kole in the Kisangani (RDC). We performed a detailed sampling in different vegetation types of a semi -deciduous rainforest (Yoko). Charcoal sampling was conducted in pit intervals of 10 cm. The charcoal was quantified whereby pottery fragments were also registered. A selection of charcoal fragments has been dated through AMS 14C measurement. Floristic identifications were conducted using. former protocols based on wood anatomy, which is largely preserved after charcoalification. Results. Charcoal was found in most pit intervals. The anthracomass in the soil of regrowth forests (secondary forests) is much higher than in the primary forest: 27,59 mg/kg for secondary forests et 2,53 mg/kg for primary forests. The specific soil anthracomass of the primary forest of the Yoko reserve is higher (7,7 mg/kg) than in Yangambi (1,9 mg/kg) , Masako (1,7 mg/kg) and Kole (0,8 mg/kg). No systematic differences have been found between soil charcoal content of the different forest type representing different forest histories. Gilbertiodendron dewevrei (De Wild.) J. Leonard forests showed surprisingly a higher concentration of soil charcoal. Discussion. Forest disturbances in the Kisangani region appear to be more recent than those in the Mayombe forest in Western RDC ( 3000-2000 calBP (Hubau, 2013)) and those of the Cameroon forest (2300-1300 calBP) (Morin-Rivat, J et al., 2014). Stratified charcoal conserved in the soil is a useful indicator of past forest disturbances. [less ▲]

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See detailQuaternary rainforests of the Northern Congo Basin: contribution of charcoal analysis
Morin-Rivat, Julie ULg; Bremond, Laurent; Gillet, Jean-François ULg et al

Conference (2014, March 27)

In comparison with the wood charcoals uncovered in the soils of the temperate regions, charcoals from the tropical regions remain little studied yet, in particular those from the dense humid forests of ... [more ▼]

In comparison with the wood charcoals uncovered in the soils of the temperate regions, charcoals from the tropical regions remain little studied yet, in particular those from the dense humid forests of Central Africa. Here we aim at showing the interest of the analysis of soil charcoals so as to understand the current environments through some examples of taxonomical identifications conducted on charcoals sampled in several soil pits in Cameroon and in the Republic of the Congo. These charcoals were hand-split then observed under an incident light microscope. The anatomical features that are hold in the charcoals and described according to a standard method were compared to wood samples from the reference collection of the RMCA. Results demonstrated that the identified species are still present in the vegetal environment today and that only limited changes occurred over the past two millennia. Charcoal analysis can thus allow a better understanding of the past history of the forests in relationship with the ancient disturbances. The temporal and spatial framework of human settlements as well as the impact of the colonial period on the evolution of the forest is also discussed. [less ▲]

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See detailIdentification des charbons de bois pour connaître l'histoire passée des forêts tropicales africaines
Morin-Rivat, Julie ULg; De Weerdt, Joëlle; Hubau, Wannes et al

Scientific conference (2014, March 26)

Nous présentons ici différents aspects de l’étude des charbons de bois à travers l’exemple de l’Afrique tropicale

Detailed reference viewed: 74 (11 ULg)