Ecology of Iranian Forest

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Tending Operation is one of the most important methods to improve equality and quantity of forest stands. In this study, two stands including non-managed (in parcel No.2) and managed stands (in parcel No.13) at the second series of "Berenjestanak" are selected to investigate the structural followed by tending operation. Thirty hectare of each parcel was selected, the statistic method was systematic and random, the netdimensions were 100×100 m and area of each sampling plot was 4000 m. The quantitative and qualitative variables of Acer Velutinum were measured in both stands. Age plantation was 20 years old and distances of each planted trees were 2 × 2 m. Thinning method was positive selection and rotation and thinning also was 3 to5 years. Thinning intensity in each rotation was14% approximately.Thinning operations was createda suitable atmosphereto select the trees. Results of this study show that the mean number in one hectare in sample stand was1365and in managed stand were 977.The average diameter of trees increased from 13.45 cm in sample stand up to 16.40 cmin managed stand. Also the volume average in one hectare increased from non-managed (164.2 m³) up to 188.5m³ in managed stand. The stability coefficient of control stand and managed stand were estimated 105.5 and 99.4 respectively. The statistical tests showed that there was a reasonable difference between the averages of quantitative parameters of two stands in 95% confidence level and equality of averages (zero hypothesis) are rejected regarding to quality, the managed parcel trees are in better conditions comparing tosample stand trees. It is concluded that tending operation had great effects on quantity, quality and stability of stand.

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      In order to study the effect of altitude on some quantitative and qualitative characteristic of Populus deltoides in Mazandaran province, three sites were selected with elevations between 150 and 1200 m above sea level in Sari city. In each site, some tree traits such as diameter at breast height, total height, basal area, volume, form factor and qualitative variables including trunk health, crown shape and trunk form were measured and evaluated and quantitative and qualitative characteristics of trees in three sites were compared using one-way ANOVA and Kruskal Wallis tests. Results showed that the altitude had significant effects on qualitative and quantitative characteristics of Populus deltoides trees and trees in lower altitude ranges (150-300 m) had a higher diameter and volume growth than trees in higher altitudes. According to results, the highest diameter (27.83 cm), height (21.13 m), basal area (0.046 m²), volume (2.11 m³) and the highest number of trees with cylindrical trunks were observed in Mahdasht. Tress in Pahnekola had the highest form factor (0.99) and with symmetrical crowns. According to results of this study, it can be concluded that planting with Populus deltoides trees in lower altitude ranges can increase the qualitative and quantitative characteristics of such trees and provides a suitable approach for supplying wood for wood-based industries.
 

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Introduction and objective: Climate change and global warming is one of the major challenges in the context of sustainable development, which is due to increasing concentrations of greenhouse gases, especially carbon dioxide. Afforestation is one of the practical and simple ways to reduce atmospheric carbon dioxide and increase carbon uptake in the soil. Therefore, the purpose of this study was to investigate the trend of soil carbon sequestration in Populus deltoides plantation located on different elevation classes.
Materials and methods: Three sites (Mahdasht, Pahnekola and NaghibdehMazde) were selected at elevations between 150 to 1200 m in Sari city. Quantitative variables including diameter at breast height, total height, basal area of all trees with a diameter more than 7.5 cm were recorded (full inventory method). Ten soil samples were taken at a depth of 0-10 cm in each site using the core method in order to study soil physical (moisture, texture and bulk density) and chemical properties (pH, EC, nitrogen, phosphorus, potassium and organic carbon).
Results: The highest diameter (27.83 cm), height (21.13 m), basal area (0.046 m²) and volume (2.11 m³) was observed in Mahdasht and the lowest values ​​were observed in Pahnekola. The lowest amount of pH (6.26±0.04), EC (0.3±0.01 ds/m), total nitrogen (0.11±0.01 %), potassium (169.49±25.00 mg/kg) and organic carbon (1.43±0.06 %) were observed in NaghibdehMazde (highest altitude). The highest and lowest rate of carbon sequestration was observed in Mahdasht (lowest altitude) and NaghibdehMazde (highest altitude), respectively. In general, in lower altitudes, poplar trees had a much better diameter growth than higher altitudes.
Conclusion: According to results, it can be stated that planting Populus deltoides in lower altitudes can be a suitable approach to reduce the concentration of atmospheric carbon dioxid.

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Extended Abstract
Background: Forests are dynamic systems that undergo continuous and permanent changes. Understanding the various elements within the forestland ecosystem and the factors influencing these elements is crucial for the preservation of these ecosystems. The preservation of species diversity plays a vital role in safeguarding the ecological values inherent in forest ecosystems. By studying various environmental factors, including vegetation, topography, soil, and climate, we can gain insights into the stability of plant communities and the correlations between these factors and vegetation dynamics. This understanding is not only important but also practical for the development and regeneration of forest communities. The significance of biodiversity and its management—especially through the protection and sustainable use of ecosystem resources—forms one of the primary objectives of natural resource management. Effective management strategies must consider the intricate relationships between species, their habitats, and the environmental factors that influence their growth and survival. This study aims to contribute to this body of knowledge by examining the unique species and rich species reserves found in the forestland region of Neimour in Iranian Noshahr. Specifically, we aim to evaluate the vegetation surrounding the Khezr Nabi swamp, a critical ecological area.
Methods: The present study was conducted in the forestland region of Neimour, focusing on the rich biodiversity surrounding the Khezr Nabi swamp. The objective was to evaluate the vegetation at the edges of this swamp, which serves as an important habitat for various plant and animal species. To achieve this, we conducted a detailed survey of the vegetation, taking into account the homogeneity or heterogeneity of the vegetation units in relation to their distance from the marsh. Ultimately, we established a zonation of marsh plants, dividing the area into three distinct zones for sampling purposes. Using the Braun-Blanquet method, we collected samples by utilizing 1×2 meter frames positioned in eight geographical directions around the swamp. This method allowed for a systematic approach to gathering data on plant species present in the area. During the growing season, we assessed plant species diversity using the Simpson and Shannon-Weiner indices, which provide insights into species richness and evenness. Additionally, we measured the richness and uniformity of species through the Menhinick and Margalef richness indicators, both of which are widely recognized metrics in ecological studies. The data collected during this study were subjected to statistical analysis to identify significant differences among the various vegetation zones and species diversity indicators. This analysis aimed to reveal patterns in species distribution and the ecological factors that influence these patterns.
Results: The results of this study, derived from the biodiversity indicators, indicated that the highest species diversity and richness were observed in the eastern, northern, and northeastern zones surrounding the swamp. Interestingly, while no statistical differences were noted in species diversity among the swamp directions, significant differences were observed in the Menhinick and Margalef richness indicators (p<0.05). Soil texture analysis revealed a composition of sandy clay loam (62.5%), sandy loam (25%), and loam (12.5%). Furthermore, significant differences were found in soil characteristics, including clay content (p<0.01), organic matter (p<0.01), and soil acidity (p<0.05). These findings underscore the importance of soil properties in influencing plant community composition and diversity.
In terms of species composition, the study found that the most prevalent tree species belonged to the beech family, which dominated the area. Among the herbaceous and fauna species, the Gramineae family and various soil ant species were most frequently observed in the northern direction. This highlights the ecological significance of specific plant families and their role in supporting diverse animal populations.
Conclusion: The findings of this study suggest that the Khezr Nabi swamp significantly influences the surrounding tree cover, fauna, and edaphic conditions, forming a unique sub-habitat characterized by a distinct microclimate. This microclimate supports a diverse array of plant and animal species, contributing to the overall biodiversity of the region. Understanding the interactions between the swamp and its surrounding ecosystem is vital for developing effective conservation and management strategies. As we face increasing environmental challenges, such as climate change and habitat destruction, preserving the biodiversity of forest ecosystems like those found in Neimour becomes ever more critical. Future research should focus on the long-term monitoring of these ecosystems to better understand the impacts of environmental changes and to inform conservation efforts aimed at maintaining the ecological integrity of this important region. By fostering a deeper understanding of the relationships between species, their habitats, and the environmental factors that shape them, we can better protect and manage our natural resources for future generations.