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Background: Measures of nutrient availability such as concentrations of carbon (C), nitrogen (N) and phosphorus (P) are important indicators of terrestrial ecosystems productivity. Current research illustrates the C, N and P stoichiometry of litter and soil in a coastal mixed forest stand, northern Iran.
Materials and Methods: To this, the Carpinus betulus (CB), Acer velutinum (AV), Pterocarya fraxinifolia (PF), Quercus castaneifolia (QC) species were considered; litter and soil (0-15cm depth) samples were taken under tree canopy cover.
Results: Litter and soil C: N ratio differed among the tree species, showing the highest (61.08 and 31.44) and lowest (21.90 and 3.59) under the QC and CB tree species, respectively. The litter and soil C: P ratio varied among the study sites and ranked in order of QC (52.4 and 27227.04) > PF (30 and 1465.61) > AV (15.74 and 630.54) ≈ CB (13.42 and 566.28). The higher amounts of litter N: P ratio were significantly found under QC (0.86) > PF (0.73) > CB (0.61) ≈ AV (0.55), whereas soil N: P ratio were significantly higher under CB (177.69) > PF (123.53) ≈ AV (121.60) > QC (109.25), respectively.
Conclusion: We found the species that differed in traits could influence C, N and P dynamics and its stoichiometry. The Q. castaneifolia species with different root traits that resulted in different vertical and horizontal distributions of C, N and P, reflecting differences in nutrient uptake by plants and microbial dynamics, drove the biggest changes in litter and soil C, N and P.

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Aim: This study investigated the variation in plant diversity, floristic quality indices, and the forest integrity of various broadleaf forest types.
Materials & Methods: In this study, we used 288 plots of 1m² in the middle Zagros forest to investigate the role of three forest types including Quercus infectoria, Quercus brantii, and Pyrus glabra on forest diversity indices and floristic quality
Findings: results revealed significant differences in Shannon wiener, Margalef, and Menhinic indices, as well as some soil properties, between forest types, but no significant differences in evenness and Simpson indices. Diversity indices mean coefficient of conservatism and floristic quality index (FQI) were significantly greater in the protected forest dominated by Quercus infectoria than in other protected forests.
Conclusion: This study demonstrates that tree species and certain topographical and edaphic factors have distinct effects on the distribution of understory plants, plant diversity, and floristic quality in different forest types. The results of this research, while confirming the use of plant diversity indices, also introduce the conservatism coefficient and species fidelity as additional tools in evaluating forest integrity, because by using them, more and better information can be obtained about the conditions of the forest.