فهرست مطالب

  • Volume:7 Issue:2, 2009
  • تاریخ انتشار: 1388/05/11
  • تعداد عناوین: 7
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  • Soleimani, M., Hajabbasi, M. A., Afyuni, M., Charkhabi, A. H., Shariatmadari, H Pages 59-70
    Soil and sediments of the estuaries and wetlands in Northwest of Persian Gulf are recently polluted with different heavy metals because of municipal and industrial wastewaters. Therefore an urgent soil cleaning up and remediation program is vital in this region. Consequently, this study was initiated to screen two plant species (Festuca arundinacea and Cynodon dactylon) for hyperaccumulation of nickel (Ni) and lead (Pb) as one of the candidate methods for cleaning-up soil and sediments of Shadegan wetland. Soil samples (0-30 cm) were collected from two sites in the wetland. The soil samples were treated with solutions of Ni and Pb separately which resulted into content of 50 and 100 mg kg-1 of metals in each soil. Thereafter, the plants were sown in the soils under greenhouse conditions and harvested after 10 weeks. Ni and Pb contents were measured in root and shoot of plants. Results showed that accumulation of Ni and Pb in tall fescue roots were significantly (P<0.05) greater than that in Bermuda grass. The amounts of Pb in root and shoot of plants were increased when soil Pb contents were increased from 50 to 100 mg kg-1 while Ni contents were only increased in the roots in response to increase in soil Ni content. The comparing of the shoot-root ratio showed that Pb accumulation in the roots of both plants was higher than that in the shoots, while for Ni was reverse. Due to difference in backgrounds of soil metal contents and soil characteristics, accumulation of Ni and Pb by plants were different in two soils
  • Gupta, B., Mehta, R., Mishra, V. K Pages 71-78
    Effect of fire on phyto-sociology of understorey vegetation in chir pine forests of three different silvological characteristics was compared with pure grassland. 15 grasses, 1 sedge, 5 legumes and 21 non-legumes were recorded in the four study sites. Floristic composition gradually increased from June to August and then declined slowly by October in all the plots. Maximum number of species was in twice-burnt plots followed by once burnt and unburnt plots. Least similarity index was recorded for twice burnt plots and unburnt plots. Density of vegetation increased from June to mid-rainy season and thereafter decreased till October. Density of vegetation in four sites decreased in order: open grassland > sapling chir pine stand > pole stage chir pine stand > mature trees chir pine stand. Density of vegetation increased when fire was imposed in plots. It decreased in the order: twice burnt plots > once burnt plots > unburnt plots. It was recorded that fire in chir pine forests are good for herbage growth and development.
  • Naghdi, R., Mohammadi Limaei, S Pages 79-86
    Information on the productivity, costs and applications of the logging system is a key component in the evaluation of management plans for the rehabilitation and utilization of Caspian forests. Skidding and road construction costs are expensive forest operations. Determining the optimum forest road network density is one of the most important factors in sustainable forest management. Logging method is an important factor to determine the optimum road network density. In this research, in order to determine the optimum road network density, skidding cost and road construction cost were calculated. Linear programming model was used in order to reduce the skidding costs and to determine the optimal forest road network density. Our aim was to determine the minimum skidding cost for Timber Jack and Clark skidders for different average skidding distance. The results showed that it is less costly if Clark skidder is used for skidding. Then the optimal road network density at this manner was 8 m/ha.
  • Mohammadnezhad Kiasari, Sh., Sagheb, Talebi, Kh., Rahmani, R., Ghasemi Chapi, O Pages 87-98
    Soil productivity and plant growth are usually affected by biological activities of earthworms. The objective of this study was a comparative evaluation of earthworm abundances in 20-year-old plantations of Alder, Oak, Maple and Cypress with the adjacent natural mixed broad-leaved deciduous forest in the Caspian region of Iran. In this research one sample plot, each 1 ha; was selected in every plantation as well as in the natural stand, more over, in each plot, 10 microsample plots 10?10m were selected random systematically. To determine the seasonal variation of density and biomass with two methods, twenty samples were taken from each microsample plot. In the first method, 10 assigned soil pits of 100?100 cm and 30 cm depth were located among each treatment and adult earthworms were collected by hand counting. In the second method, 10 circular soil samples of 81cm2 to depth of 30 cm were taken in each treatment. The larves of earthworm extracted by using Berlese funnel and were counted by binocular. Finally in four seasons a total of 400 specimens were taken from 50 microsamples in different treatments. Moreover, some site and treatment parameters were measured in each plot. The abundance and biomass of earthworms in the Cypress plantation with 148.4 (n/m2) and 4.74 (g/m2) was significantly lower than other treatments, while the differences between other treatments were not statistically significant. The two important factors were extracted from eight variables in Factore analysis. The analysis of FA showed that some treatment parameters and nutritional values of litter take an important role in seasonal variation of earthworm abundance at all the treatments.
  • Nedelea, A., Comanescu, L., Ielenicz, M Pages 99-106
    The main issues about relation between climate and relief in the Romanian geomorphological literature follow three directions of research: the description of Pleistocene glacial and Pleistocene-Holocene periglacial landforms in the Carpathians; the direct analysis of climate?s role in landform development; the integration of separate works and findings in a synthetic morphodynamic system applicable to all of the country? territory. The analysis of the present-day geomorphic landscape reveals two important generations of morphoclimatic landforms (old climatic landforms and the recent climatic relief-forms). In Romania we can identify three distinct morphoclimatic regions: the central-western region, the eastern and south-eastern region and the south-western region.
  • Ebrahimi, A., Madjdzadeh, S. M., Mohammadian, H Pages 107-112
    Twenty-seven species of Odonata were collected in the present survey in the freshwaters of South-Eastern Iran, Kerman province, in contrast to 11 species that were recorded previously from this region. In this study, 528 specimens were collected from more than 30 sites in Kerman province during 2006-2008. It seems that in this region due to its special biogeographic conditions, species diversity of this insect group is relatively high. In this research we collected African-Eurosiberian species, Anax imperator, in Kerman province which is the first record for central plateau of Iran. This species had been recorded only from northern part of Iran (Caspian Sea fringe).
  • Zeinolabedin, Y., Yahyapour, M. S., Shirzad, Z Pages 113-121
    Nowadays, a noticeable part of the relations among the states turn around the environment protection. Therefore, the right for ever-creasing use of the existing resources of this inland sea cannot be exclusive to any Caspian State and the aftermath involves all countries of this basin. In this respect, agreement on political border and boundaries with the Caspian Sea?s ecosystem is a difficult issue. The unstable resources of fish reserves, underground oil pools, migratory animals and instability of resources that so often seem to be harmful, particularly for their potential power of passing through borders, are the subject of geopolitical disputes among the states of this basin. According to the above-mentioned points, the basic question in the present article is: ?What is the role of the environmental issues in geopolitical relations of the Caspian States?? Therefore, it is supposed that a consideration of environmental issues in exploiting different resources of the Caspian Sea can set up peace among the Caspian countries.