جستجوی مقالات مرتبط با کلیدواژه « Zagros forests » در نشریات گروه « اکولوژی »

Changing the Land-uses of forests effects biodiversity and other ecosystem components. There is little information about biodiversity and soil characteristics in different Land-uses in Zagros forests. For this purpose, the effect of changing natural oak forests to coniferous plantations, deciduous plantation, rangeland, and agricultural on the biodiversity of herbaceous species and soil characteristics was investigated in the forests of Chardavol river, Ilam, in 2018. In each of the land uses, 5 square-shaped sample plots with dimensions of 20 × 20 meters were randomly taken, and in each of the main plots, four 1.5 × 1.5 square meters plots were used to check the herbaceous plant species. In order to check soil characteristics a mixed sample of soil was prepared at two depths of 0-5 and 5-15 cm in each plot. The results showed that different land uses have significant differences in terms of Shannon-wiener diversity and Margalof richness of herbaceous species. The highest value of Shannon-wiener diversity index was observed in rangeland and the lowest was observed in agricultural land uses. Also, the highest richness of herbaceous species was observed in rangeland. The results of soil characteristics at two depths showed that phosphorus and nitrogen were affected by land use and soil depth. The results show that the change in land use from the natural oak forest to agriculture and forest plantation has caused a decrease in biodiversity and richness of herbaceous species. Also, the change of land use to agriculture and forest plantation has caused an increase in salinity, bulk density, and a decrease in organic matter.

The Zagros forests are the largest forest area in Iran, and the Iranian oak (Quercus brantii Lindl.) is the most extensive and abundant tree in this forest habitat. The green oak leaf roler, Tortrix viridana L is one of the key leaf-eating pests of oak trees in this growing region. The outbreak and spread of this leaf-eating insect has many negative and economic consequences. The host trees of this pest are only Darmazo species (Q. infectori) and Iranian oak (Q. branti). This research aims to investigate the changes in the biochemical and physiological parameters of oak leaves in the areas attacked by the green oak leaf roler, in the three regions of Gurkesh Durood, Kohman El Shatter and Garit of Lorestan province, using a systematic random sampling method with a grid size of 200 x 150, 30 A sample piece of 10 AR was made with dimensions of 40 x 25 (1000 square meters). The results of this study showed that between the amount of biochemical and physiological parameters, such as cellulose, pectin, lignin, phenolic, gallotannin, proanthocyanidin, flavonoid, protein, proline, soluble nitrogen, total nitrogen in the leaves of trees with green oak leaf roler outbreak and the amount of leaf eating.

The present survey was conducted to investigate the ecological distribution range of woody species and the most important factors affecting their distribution in the Zagros forests of Ilam province. physical and chemical characteristics of soil, as well as topographical factors, were assessed in 109 circular sampling plots with an area of 500 m2 n four forest areas with an altitude range of 800-2400 m. The vertical distance of the plots on the slope aspect was 100 m, and the distance of the sampling routes varied from 500-1000 m. ecological distribution range index was calculated based on the most important factors affecting species distribution. Based on the Principal Component Analysis (PCA), the most significant factors include: the percentage of theclay, Potassium, nitrogen, carbon, sand, phosphorus, and altitude. species such as Amygdalus orientalis, Lonicera nummularifolia, Daphne mucronata and Cerasus mahaleb and Acer monspessulsnum were found at hight altitudes with the highest levels of carbon, nitrogen, potassium and phosphorus. In addition, Quercus brantii along with Acer monspessulanum and Daphne mucronata showed the highest ecological distribution range while Pistacia atlantica, Amygdalus arabica and Amygdalus orientalis species respectively has the lowest values. Overal, results indicate that topography and soil factors play an important role in the distribution of woody species in the studied areas.

Leaf litter decomposition plays a key role in the nutrient cycle of forest ecosystems. However, there is not a comprehensive understanding of the non-additive decomposition effects in leaf litter mixing experiments. In this study, the dynamics of nutrients and the rate of decomposition of Iranian oak (Quercus brantii), tree of heaven (Celtis caucasica), and wild pistachio (Pistacia atlantica) were investigated in both pure and mixed stands. For this purpose, 81 single- and double-litter bags were placed in the study area and incubated for 180 days. According to the results, at the end of the incubation period, the decomposition of oak litters in combination with tree of heaven, tree of heaven in combination with wild pistachio, and wild pistachio in combination with oak showed positive results. Based on the results, the nitrogen concentration in oak mixed with tree of heaven was higher than in its pure state. But the concentration of phosphorus in its pure and combined states did not show any significant differences. In general, the findings showed the positive non-additive effects of litter on its decomposition rate. Regarding the dynamics of nutrients, these effects were considered positive only for nitrogen.

Fires in Iran's western forests (semi-arid oak forests) are one of the main dangers in this region, which causes irreparable damage to ecosystems and the environment every year. Therefore, determining and predicting high-risk areas of fire helps to minimize the occurrence of fire and its damage by using fire risk models. The forests of Dalhu County (Kermanshah province), which are considered in the category of semi-arid oak forests, face this crisis every year and many forests prey to fire. In this research, identification and classification of high-risk areas of fire and preparation of map of high-risk areas of forest fires using Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) in the forests of Dalahu County have been done. In order prepare a map of the high-risk areas of fire in the research area, influential factors such as forest cover density, Normalized Difference Vegetation Index (NDVI) evaporation (mm), slope and direction (degrees) and elevation above sea level.meter were used. The final map was grouped into five different categories of very low, low, medium, high and very high. Finally, the results showed that Dalahou's forest fires are include areas with very low risk 14.17%, low risk 32.48%, medium risk 33.43%, high risk 17.19% and very high risk 2.7%. The results of this study can be used for sustainable development policy at the levels of natural resources and environment.

Estimators of distance sampling methods based on random spatial pattern of trees are bias in non-random spatial pattern. The purpose of this study was to evaluate the effect of spatial pattern of oak trees on the results of quantitative characteristics estimation of three different stands by nearest-individual method estimators in Chaharzabar  forests in Islamabad, west of Kermanshah province. For this purpose, three stands were selected in the area and within each stand half one hectare plot was identified. After full callipering of trees in the stands, according to completely randomized design, 30 samples with  nearest-individual method in each stand carried out. Then, spatial pattern, density, canopy cover and tree height were calculated with nearest-individual sampling method. Results showed that from the three studied stands, two stands had random spatial pattern and one had clumped pattern. Of  five estimators of nearest –individual method based on acceptable accuracy criteria (range ± 10%) for estimate density of trees, the formula proposed by Byth and Ripley in the random spatial pattern and the formula suggested by Batcheler and Bell in aggregate pattern were the most appropriate estimators. In order to estimate trees canopy cover percentage, the formulas suggested by Byth and Ripley, Cottam et al. and Morisita in the random spatial pattern were appropriate. However,  none of them were appropriate to estimate the canopy percentage of trees in clumped spatial pattern. To estimate the height of the trees, since the height was calculated independently of the estimators, it was found that estimation of the tree height by this sampling method yielded good results in both random and clumped patterns. Finally, it can be concluded that the spatial pattern of the trees was effective on the estimators of the nearest-individual distance sampling method.

The present study was performed to identify diversity indices of herb layer functional groups and its relation to physiographical factors in central Zagros forest, Lorestan. For this purpose, sampling of herbaceous plants was conducted randomly in plots of 2×2 m (n=50) in site. All plants were classified to functional groups including forbs, graminoids and legumes, also Raunkiaerchr('39')s life-forms. Diversity values (Richness, Shanon-weawerchr('39')s diversity and Hillchr('39')s evenness indices) were measured in each plot. Totally, 103 plant species were identified which belong to 27 families and 82 genera. Results indicated that aspect influenced the forbs as well diversity indices of graminoids and legumes, but slope and altitude had no effect on diversity indices. In research site, aspect had important impact on plant distribution and diversity of plant functional groups. Generally, it can be stated that ecological and managemental factors including landuse changes and grazing intensity in Zagros region influenced the plant species composition.

Road transportation is one of the most important needs of villagers, which is considered as one of the important infrastructures in the development of a region. Undoubtedly villages are better equipped with the development of communication routes, especially highways, and their problems and problems are reduced. In this research, the most important consequences and factors affecting the Khoramzal highway on the condition of foresters was using SWOT analysis method. To this purpose, using the experts' opinion, the strengths, weaknesses, opportunities and threats of highway construction were gathered using the SWOT method, and it was determined that the region is in a competitive strategy and can use the strengths to identify the effects of the leading threat points. The results of this study showed that facilitating traffic (the final weight of the factor =245.04) is the most important factor affecting the condition of foresters. Destruction of forest cover of the area (final weight of the factor=192.09) and decreasing of forests (final weight of factor=176.8) and attracting tourists (final weight of factor=103.2) are the most important weaknesses, threats and opportunities. Regarding the development of the study area, despite having a weak and simple road network (α = -0.25 β = 0.5), it has high services.