Long-term persistence of steppe vegetation in the highlands of Arasbaran protected area, northwestern Iran, as inferred from a pollen record

Palynological analysis and radiocarbon dating of a short sediment core from a high-altitude mire in the Arasbaran area of northwestern Iran reveals long-term vegetation dynamics, climate change and anthropogenic impact. Our findings indicate the prevalence of semi-desert steppe vegetation, with a variety of Asteraceae - mainly Lactuceae - species from 3000 to 1440 cal yr BP. This period is followed by a higher occurrence of Artemisia spp. and Brassicaceae (1440-1330 cal yr BP), a re-expansion of Lactuceae (1330-1030 cal yr BP) and Brassicaceae (1030-330 cal yr BP) and, finally, Caryophyllaceae species (since 330 cal yr BP). The reconstructed millennia-long dry climate in the highlands of northwestern Iran is in good accordance with climate reconstructions from other east Mediterranean sites. Two phases of moister conditions between 2100-1400 and 1000-350 cal yr BP would correspond to altitudinal Quercus-Carpinus forest expansion in the Arasbaran area. The earliest indication of anthropogenic activity in the area dates back to the onset of the record, around 3000 cal yr BP. The occurrence of small maxima of Juglans regia, Corylus avellana and Cornus mas pollen at around 1350 cal yr BP is interpreted to reflect a temporary expansion of fruit cultivation. For the last millennium the occurrence of pollen attributable to Polygonum, Euphorbia, Plantago and Rumex suggests a diversification of steppe vegetation, which may reflect intensified agropastoral activities in the Arasbaran highlands. Based on our pollen record, the regional vegetation in the Kalan area remained largely stable over the last three millennia. However, changes in local hydrology caused substantial changes in wetland vegetation

Comparison of pollen grain composition and quality of honey obtained from forest and rangeland sites in Arasbaran region

Beekeeping is one of the most important rural activities and honey is one of the most valuable by-products obtained from rangelands and some forest areas in Arasbaran region. The aim of this research was to compare the pollen grain composition and quality of honeys obtained from Vinaq (rangeland habitat) and Tazekand (forest habitat). Ten hives (10 per habitat) was established at the beginning of the flowering season in 2013. After three months, honey produced in the habitats were taken in August and was transferred to the laboratory for physico-chemical analysis and pollen identification. Pollen studies showed that the pollen grains of common hornbeam (Carpinus betulus L.) and Montpellier maple (Acer monspessulanum L.) was dominant pollen in Vinaq and Tazekand, respectively. Futhermore, the pollen grains of Lonicera iberica M. B. and Montpellier maple in Vinaq and pollen grains of Wild cherry (Cerasus avium (L.) Moench) in Tazekand were identified as companion species. According to the results of physico-chemical properties of honey samples, and particularly humidity, HMF, revival sugar, total sugar and sucrose, quality of honey obtained from forest was better than rangeland. These observations indicate that bees prefer to use of trees and shrubs pollen in compare to herbs

Assessment of Particulate Matter, Heavy Metals, and Carbon Deposition Capacities of Urban Tree Species in Tehran, Iran

Air pollution is a pressing environmental concern in urban areas, with particulate matter (PM) posing serious health and environmental threats. Urban greening has emerged as a potential solution to capture and retain PM. This study assesses the PM deposition capacity of five common tree species: Morus alba (M. alba), Ailanthus altissima (A. altissima), Platanus orientalis (P. orientalis), Robinia pseudoacacia (R. pseudoacacia), and Ulmus minor (U. minor) in two highly polluted sites in Tehran, Iran. Additionally, this study investigates the accumulation of heavy metals (Ni, Fe, Cd, and Pb), Organic Carbon (OC), Elemental Carbon (EC), and Total Carbon (TC) on the leaves of these tree species. The results demonstrate species-specific differences in PM deposition capacity, with U. minor and M. alba showing high PM retention. A. altissima exhibits strong capability in adsorbing PM 0.1–2.5, while U. minor demonstrates greater retention of PM > 2.5. Moreover, the deposition of heavy metals varies among species, with R. pseudoacacia and A. altissima capturing higher levels. This study highlights the significance of appropriate tree utilization in urban environments against air pollution in order to make the air healthier in major cities. Awareness of the different tree species capacities leads urban planners and policymakers to make intelligent decisions about urban greening initiatives to improve air quality and overall well-being

Effect of maternal tree phenotype and irrigation on survival and growth of Greek juniper (Juniperus excelsa M. B.) seedlings in Sirachal research station

The Juniperus habitat has the second most natural distribution in Iran after the pistachio. The habitat area of Junipers has decreased due to its low rate of natural regeneration which makes the rehabilitation of this species very important. The aim of this study was to evaluate the maternal treemorphology and irrigation on survival and growth parameters of Greek juniper (J. excelsa M. B.) in Sirachal research station in a four years period. Twenty produced seedlings from three different maternal treemorphology including A (cylindrical), B (non-cylindrical) and C (high production of seed) were planted in Sirachal research station as complete random blocks in split plots with three replications in 2010. Seedlings were irrigated every fifteen, thirty and forty days in the first year. Controls were not irrigated. Statistical analysis showed that in the first year, the effect of irrigation was significant on growth parameters including current diameter growth, current height growth and crown cover. The effect of maternal treemorphology was significant only on current diameter growth in the first year. In the second year, only the effect of maternal treemorphology was significant on crown cover. After four years of measurement, the effect of irrigation was significant on crown cover. According to our finding, it seems, irrigation for one time in planting time, is an important necessity for Juniper establishment and should be concerned in rehabilitation of habitats.  In addition, due to the effects of maternal treemorphology on seedlings survival, establishment and growth, using trees with C morphology will be effective in juniperus rehabilitation habitat

Vegetation-induced soil stabilization in coastal area: An example from a natural mangrove forest

Mangrove forests provide essential ecosystem services in tropical and semitropical regions by supporting their natural regeneration and other biosystem processes, offering livelihood for local communities, and contributing significantly to the natural resources. Systematic analyses on the protective role of mangrove forests and their effects on reducing coastal erosion have been carried out rarely. Mangroves form a complex ecosystem that increases substrate stabilization and dissipates wave energy favouring the deposition of fine material. This study focuses on assessing the role of white mangrove (Avicennia marina (Forssk.) Vierh.) roots in stabilizing the coastline. In a study site located in Southern Iran, a series of field and laboratory measurements were conducted on root systems that were collected from transects perpendicular to the coastline. Root samples were collected from soil cores at fixed distances from tree stems in three layers at seaward and landward positions. Moreover, Root tensile tests were conducted to estimate their biomechanical characteristics which provided the data of parameters of root reinforcement models. Also, the spatial distribution of root reinforcement and the intrinsic-variability of stabilizing components in relation to horizontal and vertical distances from the tree stem were calculated. Three models of Wu & Waldron (W&W), Fiber Bundle (FBM), and Root Bundle Weibull (RBMw) were applied. results showed that the Root Volume Ratio (RVR) and the Number of Roots (NoR) decreased with distance from the tree stem. Root tensile forces increased with root diameter. Finally, calculated root reinforcements at 0.75 m distance associated with the highest value while the lowest value was observed at 1.50 m from the tree stem. The differences between seaward and landward positions were minor. Soil detachment ratio (SDR) was approximately 10% higher at landwards positions than seaward, due to different geomorphological conditions that affected the soil detachment process. The similartity of root reinforcement values among root systems at seaward and landward positions suggest that stem density may not be an important parameter in managing mangrove forests as a coastal protection measure. Yet, RVR at different distances and NoR increasing significantly with soil depth and being different at seaward and landward positions, could improve their potential role as a nature-based solution for shoreline protection