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Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile – hence precious – meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 106 km2. Methods. The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall. Results. Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < –5; meteoroid size ≥~1 cm) amounts to 1250/yr/106 km2. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project.

Highlights• Non-destructive sampling approach applied to derive ground truth observations and generate robust basic wood densities.• Species-specific and generic allometric equations.• Specific equations have better predictive capabilities than generic models. AbstractThe quantification of the contribution of tropical forests to global carbon stocks and climate change mitigation requires availability of data and tools such as allometric equations. This study made available volume and biomass models for eighteen tree species in a semi-deciduous tropical forest in West Africa. Generic models were also developed for the forest ecosystem, and basic wood density determined for the tree species. Non-destructive sampling approach was carried out on five hundred and one sample trees to analyse stem volume and biomass. From the modelling of volume and biomass as functions of diameter at breast height (Dbh) and stem height, logarithmic models had better predictive capabilities. The model validation showed that in absence of data on height, models using Dbh only as variable was an alternative. The comparison of basic wood densities to data published in literature enabled to conclude that the non-destructive sampling was a good approach to determining reliable basic wood density. The comparative analysis of species-specific models in this study with selected generic models for tropical forests indicated low probability to identify effective generic models with good predictive ability for biomass. Given tree species richness of tropical forests, the study demonstrated the hypothesis that species-specific models are preferred to generic models, and concluded that further research should be oriented towards development of specific models to cover the full range of dominant tree species of African forests.

Although farmers have managed west African parkland savanna systems for 1,000 of years, concerns have been raised about the sustainability of these agro-ecosystems due to human population growth, shortening of fallow periods, droughts, desertification and new orientations towards cash generation away from subsistence farming. We conducted a tree diversity survey in 16 villages from Burkina Faso, Mali, Niger and Senegal, recording total species composition for 300 quadrats (mainly 50 9 20 m 2 ) that were randomly sampled from the main landuse categories of parklands of village fields (VF), bush fields (BF), sylvopastoral zone (SP) and forest reserves (FR). About 110 tree species were encountered, including 100 indigenous species. The results from balanced species accumulation curves (based on randomized subsampling of the same number of quadrats from each village) showed that the accumulated number of species was smallest in VF, largest in FR and almost equal in BF and SP, whereas classical (unbalanced) species accumulation curves yielded different results. Although there was a significant within-village reduction in species richness with increasing diameter class [averaging 8.5-13.1 more species in the smallest (\5 cm) compared to the largest diameter class ([80 cm)] for the different landuse categories, new species were also encountered in larger diameter classes (2.7-7.2 species). The evidence for tree regeneration problems (including problems in FR) suggest that farmer-managed tree regeneration should be further explored and that advances in domestication and marketing of indigenous tree species may be crucial to tree conservation in parkland systems.