D.P. Khasa’s research while affiliated with Université Laval and other places

Multi-criteria decision-making (MCDM) methods provide a framework for addressing sustainable forest management challenges, especially under climate change. This study offers a systematic review of MCDM applications in forest management from January 2010 to March 2024. Descriptive statistics were employed to analyze trends in MCDM use and geographic distribution. Thematic content analysis investigated the appearance of MCDM indicators supplemented by Natural Language Processing (NLP). Factorial Correspondence Analysis (FCA) explored correlations between models and publication outlets. We systematically searched Web of Science (WoS), Scopus, Google Scholar, Semantic Scholar, CrossRef, and OpenAlex using terms such as ‘MCDM’, ‘forest management’, and ‘decision support’. We found that the Analytical Hierarchy Process (AHP) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) were the most commonly used methods, followed by the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE), the Analytic Network Process (ANP), GIS, and Goal Programming (GP). Adoption varied across regions, with advanced models such as AHP and GIS less frequently used in developing countries due to technological constraints. These findings highlight emerging trends and gaps in MCDM application, particularly for argan forests, emphasizing the need for context-specific frameworks to support sustainable management in the face of climate change.

Agroforestry is an alternative to unsustainable agricultural practices, aiding in the mitigation of greenhouse gas emissions and climate change. However, accurately assessing the carbon sequestration potential of agroforestry tree species remains challenging due to reliance on destructive, time-consuming, and resource-intensive methods that hinder forest cover restoration in Côte d'Ivoire. Commonly used pantropical allometric equations lack specificity and precision, complicating carbon sequestration estimates. To address this, our study focused on four agroforestry species in Côte d'Ivoire: Theobroma cacao, Hevea brasiliensis, Coffea canephora, and Anacardium occidentale. We compared aboveground biomass estimates obtained using general and specific allometric equations for these species, collecting dendrometric measurements from 655T. cacao, 69 H. brasiliensis, 90 C. canephora, and 73 A. occidentale individuals. No concordance was found between generic and specific allometric equations using a linear regression model. The general equation significantly underestimated aboveground biomass by 20.06 kg, 1.10 kg, 7.28 kg, and 11.50 kg per tree for T. cacao, H. brasiliensis, C. canephora, and A. occidentale, respectively. The differences indicated a carbon sequestration potential 17.2% to 18.7% higher when using specific equations in cocoa-based agroforestry systems. This study underscores the urgency of developing customized allometric equations for more precise carbon sequestration assessments, enhancing the accuracy of agroforestry's contribution to climate change mitigation.

Protected areas in the Sudano-Sahelian zone face increasing threats from human activities. Implementing agroforestry systems (AFS) in buffer zones is recommended to mitigate these threats. We characterized AFS around Bouba Ndjidda National Park (BNNP), Cameroon, using ethnobotanical surveys and tree inventories in 50 m x 50 m quadrats. The study focused on AFS diversity, structure, woody plant diversity, and the uses of agroforestry trees and products by local communities to assess their contribution to conserving tree resources and proposing actions to reducing encroachment on the park's resources. Identified AFS included agroforestry parklands (98%), homegardens (83%), fallows (72%), and live fences (6%). Woody plant richness comprised 50 species from 42 genera and 23 families, with Fabaceae being the most dominant. Acacia polyacantha had the highest Importance Value Index at 88.65. Species richness was higher in fallows and agroforestry parklands. Live fences had the highest Shannon index and the lowest Simpson and Pielou's evenness indices. Tree density was higher in live fences ( P < 0.05) than in other AFS. Farmers used woody plant species primarily for fuelwood (66.49%) and food (63.69%). Vitellaria paradoxa recorded the highest Use Value at 4.36, while Anacardium occidentale had the highest Cultural Importance Index at 1.00. Two endangered species, Khaya senegalensis and Vitellaria paradoxa , were found in the AFS. Enriching agroforestry systems with species that produce firewood and food while promoting the protection and cultivation of endangered species is crucial for biodiversity conservation and sustainable livelihoods.

Understanding how widespread species adapt to variation in abiotic conditions across their ranges is fundamental to ecology. Insight may come from studying how among‐population variation (APV) in the common garden corresponds with the environmental conditions of source populations. However, there are no such studies comparing native vs non‐native populations across multiple life stages. We examined APV in the performance and functional traits of 59 Conyza canadensis populations, in response to drought, across large aridity gradients in the native (North America) and non‐native (Eurasia) ranges in three experiments. Our treatment (dry vs wet) was applied at the recruitment, juvenile, and adult life stages. We found contrasting patterns of APV in drought responses between the two ranges. In the native range, plant performance was less reduced by drought in populations from xeric than mesic habitats, but such relationship was not apparent for non‐native populations. These range‐specific patterns were consistent across the life stages. The weak adaptive responses of non‐native populations indicate that they can become highly abundant even without complete local adaptation to abiotic environments and suggest that long‐established invaders may still be evolving to the abiotic environment. These findings may explain lag times in invasions and raise concern about future expansions.

Agroforestry is an alternative to unsustainable agricultural practices, aiding in the mitigation of greenhouse gas emissions and climate change. However, accurately assessing the carbon sequestration potential of agroforestry tree species remains challenging due to reliance on destructive, time-consuming, and resource-intensive methods that hinder forest cover restoration in Côte d'Ivoire. Commonly used pantropical allometric equations lack specificity and precision, complicating carbon sequestration estimates. To address this, our study focused on four agroforestry species in Côte d'Ivoire: Theobroma cacao , Hevea brasiliensis , Coffea canephora , and Anacardium occidentale . We compared aboveground biomass estimates obtained using general and specific allometric equations for these species, collecting dendrometric measurements from 655 T . cacao , 69 H . brasiliensis , 90 C . canephora , and 73 A . occidentale individuals. No concordance was found between generic and specific allometric equations using a linear regression model. The general equation significantly underestimated aboveground biomass by 20.06 kg, 1.10 kg, 7.28 kg, and 11.50 kg per tree for T . cacao , H . brasiliensis , C . canephora , and A . occidentale , respectively. The differences indicated a carbon sequestration potential 17.2–18.7% higher when using specific equations in cocoa-based agroforestry systems. This study underscores the urgency of developing customized allometric equations for more precise carbon sequestration assessments, enhancing the accuracy of agroforestry's contribution to climate change mitigation.

La filière de la viande de brousse est une source d’activités génératrices de revenus pour ses acteurs mais dangereuse pour la survie de la faune sauvage à cause du non-respect du calendrier de chasse. L’impact de cette activité sur la biodiversité est l’un des principaux facteurs contribuant à la mise en place des textes juridiques pour une gestion durable de cette faune sauvage. Nous nous donnons l’objectif d’analyser les interactions entre les différents acteurs et l’efficacité des textes juridiques en vigueur pour connaître l’état de cette gestion durable de la faune sauvage au Gabon. Ainsi, nous prenons comme appui l’approche socio-écologique d’Ostrom en considérant le système de gouvernance et les acteurs dont les interactions ont des impacts sur la ressource faunique. Nous avons donc réalisé une recherche documentaire et mené une enquête qualitative à l’aide d’un questionnaire semi-directif auprès de 73 personnes. Après avoir catégorisé nos acteurs (agents de gestion de la faune sauvage – acteurs d’exploitation de la faune sauvage – consommateurs), il en résulte deux types de relations. Une relation de collaboration entre les acteurs d’un même groupe et une relation de dépendance-pouvoir entre deux groupes différents. Cependant, les textes juridiques qui permettent l’effectivité de cette dernière relation ne légifèrent que sur la chasse et non sur le commerce de la viande de brousse. Par ailleurs, certains textes juridiques devraient être actualisés et appliqués rigoureusement afin de répondre réellement aux objectifs de gestion durable de la faune sauvage et de sécuriser les métiers de ces acteurs.

Clinal variation, i.e., intraspecific variation that corresponds to environmental gradients, is common in widely distributed species. Studies on clinal variation across multiple ranges and life stages are lacking, but can enhance our understanding of specieś adaptive potential to abiotic environments and may aid in predicting future species distributions. This study examined clinal variation in drought responses of 59 Conyza canadensis populations across large aridity gradients from the native and non-native ranges in three greenhouse studies. Experimental drought was applied to recruitment, juveniles, and adult stages. Drought reduced growth at all three life stages. However, contrasting patterns of clinal variation emerged between the two ranges. Native populations from xeric habitats were less inhibited by drought than mesic populations, but such clinal variation was not apparent for non-native populations. These range-specific patterns of clinal variation were consistent across the life stages. The experiments suggest that invaders may succeed without complete local adaptation to their new abiotic environments, and that long-established invaders may still be evolving to the abiotic environment. These findings may explain lag times in some invasions and raise concern about future expansions.

Forest plantations are among the tangible solutions to meet the world's needs for timber and wood products (e.g., timber, firewood, pulp, and paper) and other ecosystem services that are constantly increasing and compensate for the loss of millions of hectares of forests caused by the increase in the severity and frequency of fires, insect attacks, and environmental stresses in humid, arid, and semiarid zones. Faced with these major constraints and challenges in the context of climate change, it is not enough to plant millions of seedlings, but we must ensure the genetic selection of seeds adapted to current and future climates, the morphophysiological quality of seedlings, the quality of sites, and the optimization of cultural as well as sylvicultural practices (e.g., from seeds to sustainable plantations) to achieve the objectives of various programs (reforestation and wood production; restoration of damaged, degraded, or destroyed ecosystems; desert greening; and agroforestry) in terms of survival, growth, and yield. This Special Issue deals with different facets and topics of the seedling production chain in different countries and continents, from growing media to planting performance related to reforestation, restoration, and agroforestry programs.

Although the evolution of principles, procedures, and predictive abilities related to seedling quality throughout the plant production chain (i.e., from seeds to sustainable plantations) has been reviewed over the past decades in various technical and scientific publications, there is still a need to develop and integrate new and efficient practices in forest nurseries and at planting sites, in order to improve the morphophysiological quality of seedlings and saplings, and their survival and growth under different site and environmental conditions in the context of climate change. We have grouped together different scientific articles in this Special Issue of Forests, entitled "Production in Forest Nurseries and Field Performance of Seedlings". They cover different topics relating to the seedling production chain in different countries and continents, from growing media to planting performance related to reforestation, restoration, and agroforestry programs.