Morocco’s argan trees, native to forests, are now cultivated in large orchards within the Argan Biosphere Reserve, transforming “Arganiculture”. These orchards are anticipated to bolster carbon storage, but their precise contribution to carbon storage remains unclear. This study introduces for the first time allometric equations for estimating biomass in different components of argan plants within orchards. A total of 89 plant individuals, aged 2 to 6 years, were collected. Their diameter and total height were measured. The biomass, carbon content, and biomass carbon stock of each component were determined. The best-fit allometric equation incorporates diameter, height, growing years, and root-to-shoot ratio to estimate total biomass (R² = 0.95). The estimated total carbon biomass stock ranged from 0.01 to 0.82 t CO₂ ha⁻¹ for plants, at a density of 200 plants ha⁻¹. Between 2021 and 2023, the average annual carbon sequestration was 0.20 t CO₂ ha⁻¹ year⁻¹. This model offers valuable tools for use when species-specific equations during the establishment growing stage are unavailable, enhancing carbon sequestration quantification for more reliable results and informing climate change mitigation strategies. The allometric parameters serve as benchmarks for trees resembling the argan tree. The methodology could be adapted for other forest plants undergoing conversion to orchard cultivation.

Assessing the impact of natural disturbances on plant biodiversity is crucial amid biodiversity loss and climate change. Research highlights dynamic shifts driven by environmental factors, climate change, and human activity, emphasizing the need to maintain ecosystem stability for biodiversity conservation and sustainable development, particularly in arid and semi-arid regions. This study, conducted between 2021 and 2023, focused on the dynamics of plant communities in argan tree reserve areas. Six argan orchards were selected as study sites for detailed investigation. A total of 82 species belonging to 25 families were identified, with 23 families documented in 2021 and 21 families in 2023, including six endemic species to Morocco (Frankenialaevis subsp. velutina, Ononisnatrix subsp. arganietorum, Rumex papilio, Andryala integrifolia subsp. cedretorum, Chiliadenushesperius, and Reseda difussa). The majority of the plants present in the study area were annual and biennial herbaceous types, exhibiting minimal seasonal stability within the plant communities. However, how communities respond to the effects of fluctuating disturbances remains unclear. This study explores the indirect effects of natural disturbances on community metrics in argan orchards, assessing plant diversity, biomass, and density across different orchard types. It highlights the influence of climate, soil properties, and biotic interactions on plant community dynamics. We utilized alpha diversity indices (Shannon, Simpson, Pielou’s, and Margalef’s) and beta diversity indices (Jaccard and Sorenson Similarity) to examine these patterns. Seasonal changes were predominantly influenced by temperature and precipitation, while diverse soil types shaped by relief, climate, and water balance contributed to different ecological functions. The key findings indicated the highest plant diversity in “Tioughza” and the most significant plant density in “Imoulass” and “Ezzaouite”. Soil nutrients (N, C, and P) showed a positive correlation with plant biomass, highlighting their vital role in biomass accumulation, whereas temperature, C/N ratio, and loam percentage were found to be crucial for plant richness. Mixed modeling revealed a significant relation between density and biomass, but no significant effect between alpha diversity (Shannon Index) and elevation. This study concludes that soil texture and climate significantly shape the relationships between diversity, biomass, and density, recommending further research into interactions among plant diversity, cover, biomass, and soil fertility to support the sustainable management of argan orchards.

Argania spinosa (L.) Skeels is a unique endemic species in Morocco, renowned for its ecological characteristics and socio-economic importance. In Morocco, recent years have seen an exacerbation of the harmful effects of climate change, leading to an alarming decline in the natural regeneration of this species in its original habitats. It seems that the only viable solution lies in the domestication of this genetic heritage. This study marks the first in-depth investigation of the impact of various climatic and edaphic factors on the morphological and physiological traits of Argania spinosa young plants, assessed in six separate orchards and observed over four seasons (March 2022 (Winter), June 2022 (Summer), November 2022 (Autumn), and March 2023 (Winter)). A climatic assessment was carried out at each site, including measurements of rainfall, maximum and minimum temperatures, mean temperature, air temperature, and wind speed. The soil was analyzed for the pH, electrical conductivity (EC), water content, limestone (CaCO₃), Kjeldahl nitrogen (N), available phosphorus (P₂O₅), organic matter (OM), and carbon/nitrogen ratio (C/N). To gain a better understanding of the morphophysiological characteristics of young argan seedlings, we carried out various observations, such as measuring the height and diameter of aerial parts, and the water content of leaves (WCL) and branches (WCB), quantifying chlorophyll (mg/m²) and leaf area. The results revealed a significant impact of edaphic and climatic factors on the morphophysiological parameters of young argan trees. Results revealed significant correlations of young argan plants between edaphic and climatic factors and morphophysiological parameters. The Tamjloujt site, characterized by protective vegetation cover, showed optimal growth conditions with the highest leaf and branch water content (46.89 ± 4.06% and 37.76 ± 3.51%, respectively), maximum height growth (91.33 ± 28.68 mm), trunk diameter (24.85 ± 3.78 mm), and leaf surface area (69.33 ± 19.28 mm²) during Summer 2022. The Saharan zone of Laqsabi exhibited peak chlorophyll concentrations (506.9 ± 92.25 mg/m²) during Autumn 2022, due to high temperatures. The mountainous environment of Imoulass negatively impacted plant growth (mean height: 52.61 ± 12.37 mm; diameter: 6.46 ± 1.57 mm) due to harsh climatic and edaphic conditions. This research provides vital knowledge regarding the environmental factors influencing the establishment of young argan plants within the Argan Biosphere Reserve. This contributes to the development of more effective domestication strategies and the restoration of agroecosystems. The aim is to use this knowledge to promote the rehabilitation and sustainability of argan agroecosystems.

Background: Extensively cultivated argan orchards in Argan Biosphere Reserve in Morocco, aged 2–10 years, were assessed to quantify ecosystem components (above-ground argan biomass, leaf litter, herbaceous vegetation, and soil) and their carbon stocks. The study was conducted in six sites over two years, from 2021 to 2023. Each site included two plots for investigation. Morphophysiological characteristics and dendrometric parameters were measured, and structural equation modeling was applied to elucidate the complex interactions among the orchard components. Argan plant biomass and soil physicochemical properties were determined. The carbon stock of each component was calculated using the 2019 Refinement to 2006 IPCC guidelines. Results: The carbon stock in total argan plant biomass ranged from 0.003 t C ha ^-1 in 2-year-old plants to 1.938 t C ha ^-1 in 10-year-old plants. The carbon stock associated with leaf litter ranged from 0.36 to 8.51 kg C ha ^-1 . Herbaceous-grass biomass carbon stock ranged from 0 to 0.56 t C ha ^-1 . The total soil organic carbon (SOC) stock varied significantly, from 10.12 to 80.5 t C ha ^-1 at a depth of 0–30 cm and from 8.49 to 75.94 t C ha ^-1 at a depth of 30–60 cm, and was identified as the dominant carbon reservoir. Conclusions: These findings provide a comprehensive analysis of carbon sequestration dynamics in arganiculture ecosystems under extensive management while supporting ecosystem rehabilitation within the Argan Biosphere Reserve. They position arganiculture as a viable component of Morocco’s Nationally Determined Contributions, aiding in carbon market integration. These findings also offer insights into the sequestration potential of similar plantations in arid regions.