NATURAL ECOSYSTEMS OF IRAN
Year:2016 | Volume:7 | Issue:1|Papers Count:8

To study of tree species diversity in relation to elevation and some of stand structure Characteristics, area about 450 ha of Hyanan forests located in north-east of Ilam city was selected.46 plots 2000m2 were established in site using transects by random- systematic method. Variables in each plot were included tree diameter (DBH), crown maximum and minimum diameter for all trees, number of trees and tree species, and data of elevation. Values of five biodiversity indices were computed by PAST software and then analyzed. Totally 6 tree species were presented in the plots which the most presentation was belong to the Quercus persica. Results showed that elevation have significantly affected on diversity, richness and evenness of tree species and the middle elevation classes had the most species richness and diversity. Evenness has the ascending trend with ascend of elevation, but decreased in 2300m from sea level. Canopy density had positive correlation with richness but negative correlation with evenness.

This study was designed to investigate the effects of gap size on seedling of oriental beech (Fagus orientalis Lipsky) survival in GAP SIZE (50, 200, 600 M2) with an open space adjacent to the nursery Avrymlk Sangdeh. In the center of eachgapwere prepared 8 plots of 2.5*2.5 m and were planted 36 seedlings in each plot. The results revealed that the percentage of survival of nurseries seedlings after the fourth growing season showed significant differences in the various gap areas. Nurseries and forest Seedlings freshness in gaps with area smaller was significantly higher than the gaps with area larger. Gap area affected on nurseries seedling significantly so that larger gaps diameter was higher. Maximum value height growth was for nurseries seedlings in 600 m2 gap. Gap effect on the terminal bud (P<...0) was significant and the greatest amount was for forest seedlings in open space.

Identification, evaluation and prioritization of different areas can produce valuable information for the watershed comprehensive plans, soil conservation and mitigation of the erosion types based on amount of erosion and sedimentation. This study used the MPSIAC and EPM models as a comparison and prioritization to estimate erosion and sediment in the Aro Watershed Basin. Required data regarding the natural characteristics of studying the watershed basin was provided from comprehensive studies of Hableh-Rood basin and field studies. By using the required factors, the amount of erosion was calculated in both the models. In the MPSIAC model, erosion was calculated to be 451 m3/km2/y, whereas sediment was calculated as 233 m3/km2/y. However, the rate of erosion in the EPM model was estimated to be 378 m3/km2/y and for sediment, it was 200 m3/km2/y. The results showed that in some sub basins there was good correlation between the MPSIAC and EPM models, however in areas with high erosion the EPM model has less certainty than the MPSIAC model. The highest area was moderate class in the both of models and both of erosion and sediment in terms of spatial distribution. The results showed that EPM and MPSIAC model have not good agreement in the all classes. Prioritization of the hydrologic units showed that A4 unit in the EPM model and A-1-4-3 unit in the MPSIAC model allocated maximum of amount of erosion and deposition, in this area.

Relationships between environmental factors and vegetation is an essential step in order to recognize the effective factors on growth and establishment of species plants and identify habitats. The purpose of this study was investigation of relation between environmental factors and rangeland habitats and to determine the most important affecting factors in the segregation of rangeland habitats of Southeast Sabalan, which is located in Ardabil province. Sampling was done using random-systematic method. In this rangeland ecosystem, sampling was conducted with the selection of 45 sites in southeast of Sabalan, and inside of each site 3 large 10 m2 plots with the distance of 40m from each other along of a 120m transect was selected. Inside of the plots, the list of the plants and canopy cover were determined. From these plots, soil samples were collected from two depths of 0-15 and 15-30 cm and the climatic characteristics such rainfall and temperature, topographic features suchas elevation, slope and aspect, soil features such texture, electrical conductivity, acidity, organic matter (C), phosphorus and potassium were measured. To determine the relationship between environmental factors and plant distribution based on each plots a multivariate analysis (ordination) was used. Ordination of plant communities based on environmental factors using Canonical Correspondence Analysis (CCA), De trended Correspondence Analysis (DCA) and Representational Difference Analysis (RDA) methods was performed. Results indicate that on the study area, physiographic attributes (elevation and aspect) have significant effects on the distribution of rangeland habitats. The CCA results of environmental factors indicate that the first and second axes with eigen values 0.703 and 0.519 and variance 11.5 and 20 respectively justify habitat changes and environmental factors in the study area. The results of this study can be used in the management of rangeland ecosystem improvement and remidation of the Southeast Sabalan and the same areas.

The aims of this research are increase rangeland production of deserts of central Iran and modification of the prevailing conditions fragile wilderness areas through proper identifying the species and planting them in came into force. In this study, three species: Seidlitzia rosmarinus, Nitraria schoberi and Zygophyllum eichwaldii by planting potted seedlings treated without operation rippering (breaking the hard layer) was conducted in a split plot based on randomized complete block design. Rainfed culture was conducted in March and only in the first year of planting and irrigation was 3 times per year. Traits within 3 years of the project, including survival, height growth, vegetation canopy and production. Statistical analysis of the data showed that the effect of ripper stay survival, height growth on Seidlitzia rosmarinus meaningless and maximum vegetation canopy diameter (121.7cm) and production (978 gr) were treated without treatment. Nitraria schoberi was not affected by the plant survival ripper, but the highest growth in height (63.7 cm), vegetation canopy diameter (100 cm) and production (1413.3 gr) was treated ripper. Ripper treatment on Zygophyllum eichwaldii consists of all the characters and most survival (86%), high (63.4 cm), vegetation canopy diameter (73.4 cm) and production (287 gr) treated with ripper has been made. Therefore, Manysurvival and vegetation canopy rate, priority of culture in the region Seidlitzia rosmarinus, Nitraria schoberi and Zygophyllum eichwaldii, respectively. The ripper do not effected on growth and survival of Seidlitzia rosmarinus but affected on survival, height growth, canopy and the production of the Nitraria schoberi and Zygophyllum eichwaldii species.

In this study trees crown covering and rooting effects on soil characteristic variability were studied. For this purpose, 4species include: pinus nigra, Cupressus arizonica, Fraxinus rotundifolia and Robinia pseudoucacia were selected with 43 years–aged Afforestation in Hasnabad–Sanandaj 22 rectangle sample plot (900m2) were chosen and allometric trees data include: DBH, height and Crown diameter were measured then annual DBH & height increment were calculated. We computed crown covering percentage in plot after 43 years. Then 112 Auger soil samples in 0-20 and 20-40 cm depth around of selected trees were taken afterward subsequently physical and chemical soil characteristics were determined Roots separated by washing then volume, wet weight and dry weight were determined. Cooperation physical and chemical soil properties under canopy and around tree in different variation shown that after 43 years effervesce on soil characters. Finally pinus nigra introduce as the best afforestation and much compatible species.

The aim was to find out the relationships between three classes of regeneration (lower 0.5 m, 0.5 – 1.5m, and higher 1.5 m) with canopy cover percentage (four classes: 1-5%, 5.1 – 12%, 12.1 – 25% and 25%<), slope (three classes: 0 – 30%, 30 – 60% and 60%<), and aspect ((four classes: N, S, E and W). In order to investigate the natural regeneration in the Zagros forests, a forest area of 200 ha located in Blouran region, West part of Kuhdasht city, was selected. A number of 90 sample plot with an area of 1000 m2 (network dimensions of 20×50 m) were sampled. Result showed that high forest regeneration was scarce relative to those of coppice. Q. Branti had maximum number of regeneration. The maximum number of regeneration was less than 0.5 m in height. Maximum number of regeneration was observed in the canopy cover of 12.1 – 25% class (65.13). The slope class of 30 – 60 percent showed the maximum number of regeneration in all height classes (73.59). Maximum regeneration in the South aspect, and this was the maximum number of. It is noteworthy to consider the natural regeneration of the Zagros forest with reference to seed development to regeneration as well as regeneration establishment in several physiography, climate and edaphic conditions.

The sustainability of forest ecosystems a dependent on soil quality in duration time, consequently knowledge of forest soil situation and effects of land use on soil properties is very important for forest management. Degradation of zagros forest is caused that restoration those be very important. The purpose of this study was determination of relationship between altitude, slope and canopy on soil chemical properties. The study was carried out in Tang-e-Dalab in Ilam province on northern slope. Three transects were sampled in oak stand (Quercus brantii). In each transect, samples had 50 meters interval. Soil samples were collected from soil surface (0- 02 cm). Then Samples separately were located inside and outside of canopy in each transect. Overall were collected 60 samples. In each sample, altitude from sea level and slope percent were recorded. The results showed exchangeable K and Mg, EC decreased by increasing altitude in both inside and outside of canopy but pH has direct relationship with altitude. Moreover increasing of slope percent exchangeable K and Mg, EC, pH decreased in both inside and outside of while there was inverse relationship between exchangeable Ca and altitude and slope inside canopy, but outside canopy it had direct relationship.