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On the outskirts of the city of Bangui, the capital of the Central African Republic, fuelwood production, slash-and-burn agriculture and artisanal timber exploitation are causing deforestation and forest ecosystem degradation. Within the framework of the REDD+ Component of the South-West Regional Development Project, the implementation of Assisted Natural Regeneration during weeding (ANRw) in the slash-and-burn system was proposed and set up by 23 volunteer farmers on 24 fields with an average area of 0.22 ha in two villages (Boteke and Salanga). The objective of the study was to characterise the floristic structure of the juvenile woody vegetation resulting from ANRw in these two villages. More specifically, it aimed to: 1) describe the methods used to inform and raise awareness amongst farmers who volunteer to practise ANRw; 2) identify the main species conserved by the farmers; 3) identify the reasons or factors that motivated farmers to choose these species; 4) identify the biological and ecological characteristics of these species; and 5) evaluate the height growth of young trees preserved by ANRw over a 14-month period. The third inventory of the 24 plots (volunteers' fields) gave 1,668 woody plants preserved by ANR on 5.35 ha (312 trees ha−1), divided into 42 genera, 47 species and 23 families. These results show that ANRw is a simple technique to implement and can help maintain trees in fields in areas where pressure on the forest is high. In the supported villages, communities have shown an interest in applying this technique to reintroduce trees in the fields. This technique should be popularised in other places to improve the sustainable management of anthropized forest landscapes. In addition, volunteers who have tested ANRw say they are willing to continue practicing it. However, despite this genuine initial enthusiasm, this restoration drive will need to be monitored and supported due to the current context of extreme poverty and economic, social and p

Background: In the traditional slash-and-burn system, widely used in southern CAR, the forest is felled and then burnt, and maize, followed by cassava and banana crops, are planted in the ashes. Three or four years later, the plot is abandoned and left fallow without any management until its next clearing. A study of the evolution of the landscape south of Bangui, the country's capital, shows that this practice leads to the retreat of the forest, replaced initially by a patchwork of degraded forest and Chromolaena odorata scrub, then by Imperata cylindrica savannahs where agriculture becomes almost impossible. To avoid this degradation of ecosystems, leading to soil impoverishment, biodiversity loss, carbon emissions and the flight of populations, the PDRSO project introduced farmers in several villages to an Assisted Natural Regeneration (ANR) technique that protects young trees during the cropping cycle so that a stand of trees, and not invasive bushes and grasses, later occupies the land during the fallow cycle. Method: A negotiation phase between the farmers and the researchers made it possible to choose the species of interest and the technique to conserve them. Monitoring of 24 plots with ANR and 20 control plots without ANR, made it possible to assess the growth of woody plants. Surveys of farmers who had participated in the operation and those who had not, allowed us to assess their perception of the method and their willingness to continue it over time. Results: Two years after being selected, the young trees already are larger than the main invasive species and are impeding their establishment In addition, the farmers see the importance of preventing their village territory from being transformed into barren savannah. Difficulties reported include insecurity of land tenure, lack of support from the administration, the brevity of projects, and the difficulty of fighting fires due to lack of collective organization, all in an environment of civil war. Discus

Wood density (WD) relates to important tree functions such as stem mechanics and resistance against pathogens. This functional trait can exhibit high intraindividual variability both radially and vertically. With the rise of LiDAR-based methodologies allowing nondestructive tree volume estimations, failing to account for WD variations related to tree function and biomass investment strategies may lead to large systematic bias in AGB estimations. Here, we use a unique destructive dataset from 822 trees belonging to 51 phylogenetically dispersed tree species harvested across forest types in Central Africa to determine vertical gradients in WD from the stump to the branch tips, how these gradients relate to regeneration guilds and their implications for AGB estimations. We find that decreasing WD from the tree base to the branch tips is characteristic of shade-tolerant species, while light-demanding and pioneer species exhibit stationary or increasing vertical trends. Across all species, the WD range is narrower in tree crowns than at the tree base, reflecting more similar physiological and mechanical constraints in the canopy. Vertical gradients in WD induce significant bias (10%) in AGB estimates when using database-derived species-average WD data. However, the correlation between the vertical gradients and basal WD allows the derivation of general correction models. With the ongoing development of remote sensing products providing 3D information for entire trees and forest stands, our findings indicate promising ways to improve greenhouse gas accounting in tropical countries and advance our understanding of adaptive strategies allowing trees to grow and survive in dense rainforests.