Agroforestry systems across elevational gradients in northern Iran

Agroforestry systems, by promoting biodiversity and optimizing resource use, can enhance ecosystem services and mitigate environmental challenges across different elevation zones, from lowlands to high-altitude regions. By examining the role of agroforestry across elevational gradients, this paper seeks to highlight the potential of agroforestry systems in addressing the challenges and opportunities faced by farmers in different altitude zones. To achieve this, two provinces within the Hyrcanian region were selected: Mazandaran (Kalardasht County), representing the semi-humid highlands, and Guilan (Rasht County), representing the humid lowlands. This study was conducted in two sections: socio-economic and biological evaluation. 116 questionnaires were completed, with 56 from the uplands and 60 from the lowland regions. To analyze and compare biodiversity, indices such as richness (Taxa_S), diversity (Shannon_H), and equitability (Equitability_J) were calculated. Results shows that about 93 % and 69 % of farmers were involved in agroforestry activities in lowlands and uplands, respectively. In upland area, the most commonly planted species is poplar (47 %), followed by walnut and peach (both 11.7 %). Other species, such as sour cherry and pine, are less common. In lowlands, poplar is also the most prevalent species (65.5 %), followed by walnut (14.7 %) and orange (8.2 %). The results showed that the density in lowlands (66 ± 74 trees per hectare) was lower than in uplands (403 ± 127 trees per hectare). The taxa index in lowland (1.5 ± 0.18) was lower than in upland (3.46 ± 0.38), suggesting a lower species diversity in Rasht compared to upland. The variation in forest characteristics across elevation zones also has important implications for agroforestry and conservation strategies. In lowland areas, where tree volume and basal area are higher, agroforestry systems can be designed to maximize tree productivity, potentially providing greater carbon sequestration benefits. In upland regions, however, efforts might focus on enhancing tree density and species diversity to compensate for slower growth rates and reduced biomass. Additionally, managing these differences through targeted conservation and land-use practices is crucial for sustaining biodiversity and ecosystem services across different altitudinal gradients