Deforestation in tropical dry forest ecosystems is one of the primary causes of a reduction in biodiversity for flora and fauna worldwide. In response, ecological restoration has become a strategy to recover and reverse such degradation. These activities are part of the goals of the United Nations’ Sustainable Development Goals and Decade on Ecosystem Restoration (2021–2030). Restoration begins with characterising phenotypic diversity, which provides the basis for selecting tree individuals with desirable traits to serve as seed sources in natural forests. These sources would further feature high adaptability and productivity – factors that enhance seed propagation in nurseries, enabling their subsequent multiplication and implementation in specific areas for restoration processes. The objective of this research was to conduct a systematic review to characterise the current landscape of ecological restoration in tropical dry forests across key South American regions, including the Cerrado and Caatinga in Brazil, the Gran Chaco in Argentina, and the tropical dry forest of the department of Huila in Colombia. The importance of seed sources in restoration programmes was described, and the advances in the implementation of forest species as seed sources were highlighted. To do this, a systematic review was conducted using data from Web of Science, Scopus, and SciELO, with statistical analysis performed in the software R. The results identified 671 articles, and of these, 60 articles were considered to meet the appropriate criteria for carrying out the study. Finally, the seed sources used in restoration processes in hotspots such as the Cerrado, Caatinga, the Gran Chaco, and the tropical dry forest of the Huila region have had a great impact on the recovery of tropical dry forest through assisted restoration, where the availability of high-quality seed and plant material is ensured.

This study aimed to characterise extracts from six tropical hardwoods of Cote d’Ivoire, notably Milicia excelsa (iroko), Khaya ivorensis (mahogany), Triplochiton scleroxylon (samba), Gmelina arborea (gmelina), Piptadeniastrum africanum (dabema), and Acacia mangium (acacia), through macromolecular quantification, FTIR, and GC–MS analyses. The objectives were to evaluate solvent-dependent extraction yields, to identify and classify major groups of extractives, to assess polysaccharide and lignin composition across species, and to highlight metabolites of industrial and biological significance, including those reported here for the first time. Extraction yields varied markedly among species. Gmelina arborea (gmelina) displayed the highest levels, exceeding 10%, particularly in dichloromethane fractions rich in polar compounds. Iroko and mahogany showed intermediate yields between 6 and 8%, enriched in phenolic fractions, while dabema, acacia, and samba produced lower amounts. FTIR spectra revealed characteristic hydroxyl, carbonyl, and aromatic absorptions, in agreement with the chemical families confirmed by GC–MS. This analysis identified a wide diversity of metabolites, such as chlorophorin, catechin, resveratrol, lupeol, gmelinol, and major fatty acids, including palmitic and stearic acids. Notably, gmelinol in Gmelina arborea and oxyresveratrol in iroko are reported here for the first time in Ivorian hardwoods. In addition, the polysaccharide and lignin contents varied considerably among species. Cellulose ranged from 29.65% in iroko to 42.01% in acacia, holocellulose extended from 69.33% in dabema to 74.69% in acacia, and lignin fluctuated between 21.54% in acacia and 28.49% in gmelina. These variations reflect interspecific differences in wood structure and may partly account for the diversity of extractive profiles and durability. Overall, the results highlight the significant bioactive potential of Ivorian hardwoods and support the valorisation of sawmill by-products as sustainablesources of high value-added compounds.

Trois chercheurs, Véronique Mure, Philippe Birnbaum, et Jacques Tassin, rendent hommage à Francis Hallé, botaniste et défenseur passionné des forêts tropicales et du monde végétal, disparu fin 2025. Son engagement inébranlable pour la cause des arbres et des forêts a marqué des générations d’étudiants, de chercheurs et de passionnés. Véronique Mure souligne son rôle de passeur de savoir et d’émotion. Francis Hallé enseignait la botanique avec une approche à la fois scientifique et poétique, mêlant rigueur et sensibilité. Ses cours, ses dessins et ses expéditions, comme le célèbre Radeau des cimes, ont révélé la beauté et la complexité de la canopée, un univers alors méconnu. Pour lui, la beauté des plantes n’était ni accessoire ni décorative, mais une valeur fondamentale du vivant. Philippe Birnbaum évoque la proximité unique que Francis Hallé entretenait avec les arbres, qu’il considérait comme des êtres supérieurs dans l’évolution du vivant. Refusant de les comparer aux animaux, il les étudiait avec lenteur et contemplation, valorisant leur autotrophie et leur sophistication. Son influence a renforcé la vocation de nombreux étudiants, malgré les pressions sociales, et il a légué une vision humble et attentive du monde, à l’écoute des arbres. Jacques Tassin décrit Francis Hallé comme un poète et un philosophe du végétal, doté d’un « œil absolu » pour décrypter les formes et les mystères des forêts. Son ouvrage Éloge de la plante a marqué les esprits par son approche pluridisciplinaire, mêlant science, poésie et spiritualité. Homme de raison et d’intuition, il savait capter l’immatériel et transmettre son émerveillement pour le vivant, laissant une œuvre scientifique et une pensée qui continuent d’inspirer. Francis Hallé reste un modèle d’engagement, de curiosité et d’humilité, ayant su allier science, art et militantisme pour défendre la place centrale des plantes dans notre monde.

The objective of this study is to convert agricultural residues, particularly cocoa pod shells from the Ivory Coast, into low-cost bioadsorbents. In this context, biochar can be produced from agricultural residues for use in removing water pollutants. The main question was whether the adsorption efficiency of biochar produced from this biomass can be improved by physical activation with carbon dioxide (CO₂). To this end, an assessment was made of the effectiveness of raw and activated biochar in adsorbing cadmium (Cd2⁺) from an aqueous solution under conditions close to those of drinking water (pH = 6 and temperature = 22 ± 1 °C). The results of the adsorption indicated that raw biochar, obtained by pyrolysis of cocoa pod shell biomass at 400°C, was more effective at removing Cd2⁺ (removal rate = 72.0 ± 1.1% and adsorption capacity = 14.4 ± 0.3 mg/g) than activated biochar, which was produced by pyrolysis of the same biomass at 900°C followed by activation with CO₂ at 800°C (removal rate = 65.3 ± 1.8% and adsorption capacity = 13.0 ± 0.4 mg/g). The experiment indicates that the chemical surface properties of adsorbents significantly influence the adsorption of Cd2⁺, while physical properties have a minor impact. This study revealed that raw biochar pyrolysed at 400 °C was more efficient than activated biochar in adsorbing Cd2⁺, thus offering an easily available, environmentally friendly, and inexpensive adsorbent for improving drinking water quality. Therefore, it is not systematically necessary to activate biochar to be effective in removing pollutants from water.

Tool wear is a major issue in the forest industry, and extensive research has been carried out to understand its causes and to limit tool degradation. Among these causes, the properties of the machined wood—highly variable between species—play a crucial role. Sixty years ago, André Chardin (d. 1987) conducted a 15-year experimental study on tool wear during the sawing of tropical woods. Out of 4,000 cutting tests, 835 standard tests with uniform chip thickness were performed on 554 trees representing 285 species, 200 genera and 59 families, at both green and air-dry moisture contents. The tested woods were highly diverse, reflecting the wide variability typical of tropical species. Tool wear varied greatly, partly due to plastic bending of the cutting edge under high mechanical stress. The relationship between tool tip recession and cutting length followed a power law with a median exponent of about 0.7, which was lower for tests showing tip bending and for dry wood compared with green wood. Silica content emerged as the dominant factor influencing wear, given its large variation among species, while extractive content was not significant. Wood density and moisture content also affected wear, though to a much lesser extent. Grouping the tests by moisture (dry versus green) and silica content (siliceous versus non-siliceous) highlighted the combined effects of density and moisture on edge recession. Tool tip bending occurred frequently (42%) for dry non-siliceous woods, less often (10%) for dry siliceous or green non-siliceous woods, and rarely (3%) for green siliceous woods. Tool face burning was also common (42%) in dry non-siliceous woods. For the 78% of tests without tool tip bending, progressive linear regression on logarithmic wear and wood parameters yielded a 58% predictive value: silica (42%), moisture (8%), specific gravity (7%), and extractives (0.4%). The minimal impact of extractives contrasts with their known influence on steel corrosion and friction, likely due to opposing effects of different extractive compounds across species.

The Brazilian planted forest sector plays a vital role in economic and environmental sustainability, favouring mechanisation to meet market demands. However, studies addressing operational performance in the northeastern region remain scarce, particularly under varying site and stand conditions. Moreover, there is a lack of predictive models that link forestry forwarder productivity to operational costs and extraction strategies adapted to local site variability. It is noteworthy that forest extraction in Brazil faces challenges due to the variability of edaphoclimatic conditions, impacting forestry forwarder productivity and operational costs. This study aimed to evaluate how specific operational factors (such as extraction distance, forestry forwarder load capacity, forest productivity, and time allocation within the machine's operational cycle) influence the efficiency and costs of timber extraction. Field data were collected in southern Bahia, a strategic area for the pulp and paper industry, across stands with distinct productivity levels and forest rotations. Time and motion studies, linear regression, and cost analysis revealed that predictive models explained up to 92% of forestry forwarder productivity. A strong inverse correlation was found between productivity and extraction distance. This result highlights the importance of minimising long hauls to reduce costs. Productivity was directly proportional to forest yield, with the forestry forwarder loading process representing up to 42% of the operational cycle. The use of higher-capacity forestry forwarders has optimised extraction, with an average of 21 m³ per trip. Cost analysis showed a 26% increase in cost per cubic metre with decreased forest yield and a 61% increase with longer extraction distances. These findings define optimal operational parameters for Southern Bahia, Northeastern Brazil, emphasising cost-efficiency and performance improvements.

Le Laboratoire d'Ecologie Terrestre de Toulouse a mis sur pied, les 10 et 11 juillet1997, un symposium sur la mangrove et les différents aspects de la recherche concernant son écosystème, dont les organisateurs étaient : R.Dooo, f. FROMARD, Z. RAFII.

Sachant qu'il est toujours difficile de rassembler des statistiques à l'échelon européen ou mondial, nous avons demandé à Eric B0ILLEYde nous faire part de certaines données sur le commerce des bois tropicaux, fournies en grande partie par l'U.C.B.D. (Union pour le Commerce des Bois Durs en Europe), qu'il a analysées pour les lecteurs de Bois et Forêts des Tropiques.

Fiche descrivant les propriété physiques, mécaniques, et techniques de l'essence de bois Didelotia africana, Didelotia letouzeyi, Didelotia p.p.

To use wood species appropriately and optimally, it is imperative to know their chemical composition. The application of near-infrared spectroscopy (NIRS) provided a valuable approach to correlate wood properties with tree ecological traits and their adaptive responses. The study aim was to verify that different chemical compositions exist for a wide range of species grouped into distinct ecological temperaments. Thus, 25 tropical Gabonese hardwoods, mainly secondary species, were studied and divided into three ecological temperaments: pioneer, hemi-heliophilous, and shade-tolerant. The spectra studied were obtained using a Spectrum Two N spectrometer (PerkinElmer) on the transverse faces of 368 unground samples of heartwood by reflectance in the range 1000 to 2500 nm. These were then subjected to pre-processing (standard normal variable and second derivative), followed by principal component analysis and partial least squares discriminant analysis. The discrimination model used showed high performance in cross-validation and prediction at 93.2% and 88.3%, respectively. The results indicated differences in NIRS signatures between the three ecological temperaments. The hemi-heliophilous and shade-tolerant species had similar NIRS signatures but different concentrations of chemical compounds (derived from NIRS spectra analysis). The pioneers had a different profile from the other two ecological temperaments. No significant difference in cellulose content was found between the three ecological temperaments. Hemicelluloses and lignin concentrations were higher in the shade species. The pioneer species had significant levels of extractives.