Caspian Journal of Environmental Sciences
Volume:8 Issue: 2, Spring 2010

Five treatments including Conway medium, media containing 0.1, 0.17, 0.3 and 0.5 mg l-1 ferrous (Fe; in the first experiment), media with 1, 1.26, 1.59, 2 mg l-1 concentrations of phosphorous (P; in the second experiment) and a pure sample of Tetraselmis suecica were cultured under laboratory conditions. Growth rate of the algae was determined using the optical density method at 750 nm and number of algal cells were counted with a hemocytometer. The results of the first experiment showed that the amount of Fe for maximum growth of this species was 0.3 mg l-1, while Fe concentration in Conway medium was 0.27 mg l-1 (P>0.05). The results of second experiment showed that 1.59 mg l-1 P caused the maximum growth of algae which was not significantly different from that of the control medium (with 1.6 mg l-1; Conway; P>0.05). These results showed that due to the lack of significant differences in maximum growth of this alga recorded in 0.3 mg l-1 Fe and that recorded in 1.59 mg l-1 P in Conway medium, increase or decrease of these doses will have a significant negative effect on algal growth.

The study was carried out in the Ilam Oak forest that is located in the west part of Iran. The objective of this research was to determine the plant ecological groups and site classification in this region. Data were collected from 117 sample plots using the systematic-random sampling method. The size of sampling plots was 20 m?20 m for the tree and shrub species and 1.5 m? 1.5 m for herbaceous species. Whittaker?s nested plot method was used in order to record the herbaceous species. Soil samples were collected and analyzed to study soil properties. Multivariate analysis methods were used to classify and determine the relationship between species composition and environmental factors and to recognize ecological species groups. PC-ORD and SPSS software were used for data analyzing. Five ecological groups were specified in the study area. Cerasus microcarpa was the indicator species in the first group, which showed high correlation with carbon and nitrogen. Quercus brantii showed the strongest correlation with CaCO3. The third group was Acer monspessulanum. Elevation and clay were the most important factors that separated this group. Amygdalus orientalis showed high correlation with elevation. These two above mentioned groups were located in higher altitude. Astragalus liyciodes was the indicator species in another distinct group in the study region with high level of stoniness percentage. Astragalus group was observed where soil stoniness was high. Results also showed that groups at higher elevation showed lower richness.

The diversity and distribution of the rotifers family Notommatidae was studied in the northwest, the south and the southwest of Iran. In total, 29 species were identified, of which, 25 are new records for the country. New records include the following species: Cephalodella forficata, C. cf. mus, C. vittata, C. ventripes, C. lepida, C. inquilina, C. gibboides, C. tincaformis, C. obvia, C. sterea, C. physalis, C. gracilis, Eosphora najas, E. Ehrenberg, E. therina, E. anthadis, Eothina elongate, Monommata actices, Notommata pygma, N. glyphura, N. diasema, N. brachyota, Resticula nyssa, R. melandocusa and Pleurotrocha atlantica. Spatial and temporal patterns of the species diversity were evaluated. Descriptions are provided for all the identified species in detail. Biogeography and environmental conditions favorable for identified species were referred. A great richness of rotifers in aquatic environments is generally found in regions where vegetation predominates, either in aquatic or in the ecotone zone between aquatic and terrestrial environments.

The aim of this study was to investigate relationships between soil properties and plant species to determine the most effective factors separating vegetation communities in Rineh rangeland. Three stratifying variables were selected including slop, aspect and elevation. The study area was partitioned by combining these classes to generate homogenous units. 1m2 quadrates were located at sampling sites in each homogenous unit randomly. Vegetation cover data were recorded using ordinal scale of Daubenmire cover-abundance scores in each quadrate. Soil samples were collected based on area from 0-15, 15-30 cm depths in each sampling site. Total nitrogen, organic matter, pH, total phosphorus, water retention capacity, permanent wilting point, available water capacity, potassium, water holding capacity, CaCO3, saturation moisture, bulk density, real unit weight and percentage of fine earth fragments (sand, silt and clay) were measured. Both classification and ordination techniques were employed including TWINSPAN classification, DCA and CCA. The TWINSPAN classification of the sample sites have resulted in ten groups. According to the results of DCA, length of gradient represented by axis 1 was >5 SD, indicating that CCA was the appropriate ordination method. CCA axis 1 was correlated to phosphorus (-0.460) in the first layer and phosphorus (-0.493), sand (0.533) in the second layer while the CCA axis 2 was correlated to phosphorus (0.394), sand (0.533) in the second layer. The species-environment correlations are higher for the first three canonical axes, explaining 18% of the cumulative variances.

Forest road construction is the most costly operation in forestry. Road designing and construction in unsuitable areas may increase construction and maintenance costs and also cause many environmental impacts. Therefore, it is required to pay more attention to forest road design. In this research, we tried to introduce an appropriate method for locating forest roads using GIS and AHP simultaneously. The most important layers in locating forest road include slope, soils type, geology, hydrographic networks, aspects, trees volume m3 per hectare, tree type and elevation maps which were determined and then by using expert thought and AHP method the study area was classified in five classes including very good, good, medium, bad and worse for forest road construction. Then two new variants were designed on the prepared AHP map: the first variant was designated using traditional method and Pegger extension was applied to design the second. Pegger Planning variant (PP_variant) had the highest efficiency in path from good and bad points of view based on AHP map. The results of this study illustrated that using AHP and GIS simultaneously can introduce an appropriate and suitable method in the forest road network planning.

This research was conducted to investigate spatial variability and estimate tree attributes in a plantation forest in the Caspian region of Iran using geostatistical analysis. Sampling was performed based on a 50m?125m systematic grid in a maple stand (Acer velutinum Boiss) 18 years of age using circular samples of 200m2 area. Totally, 96 sample plots were measured in 63 hectares and 14.25 hectare was inventoried as full census area. Experimental variograms for forest stem basal area, stem density and tree height attributes were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of basal area and height showed a high spatial auto-correlation, which is fitted by spherical model. However, stem density showed a large nugget effect. Estimations for basal area and height interpolated by ordinary block kriging and cross validation results showed that all the estimations were accurate. Furthermore, the estimated kriged mean of basal area showed no significant difference to the real mean in the full census area. Therefore, geostatistical analysis is able to capture and explain the spatial variability as well as estimate tree attributes (not stem density) in this kind of plantation forest, accurately.

In the Shafaroud forest, logging operation is generally performed by using selective cutting methods. Chainsaw and cable skidder are two main forest machines for harvesting of this forest. However, forest harvesting operations result in serious residual stand damage during felling, winching and skidding operations in this forest. Residual stand damage resulting from selective cutting was assessed on Avardim district in the Shafaroud forest in the north of Iran. Logging operation was performed by chainsaw and cable skidder. To gain benefit of directional felling, Landing and skid trail was planned prior to felling. Study area was cruised using 14 random sampling plots centered on transect lines uniformly distributed throughout the harvested area. Study results indicate majority of the injuries that occurred belong to the skidding and winching stage and the bole portion of tree (> 1m). Beech trees were injured more than trees of other species, and the mean area of injury was 290.3 cm2. Investigation on felling error showed that 40% of felled trees were at an angle of about 45-70 degrees with skidding direction, therefore felling crew could not lead the felled trees toward the skid trails. Increase felling error made the remaining trees more susceptible to injuries. This research indicated that preliminary planning of skid trail prior to felling is not a sufficient measure to minimize residual stand damage but proper training of crew is essential to insure a good performance of the operation. Felling crew should be not only trained and experienced workers but also aware of the value of residual crop trees, and the importance of minimizing stand damage if uneven-aged stand management practices are to be successful

This study aims to investigate the relationships between people?s livelihoods and the woodland resources of the Ganaveh watershed in southern Zagros, Iran, as a basis for suggestions of strategies for sustainable management of the woodland resources and improvement of the livelihoods of people in the community. Household data were collected through interviews with heads of households and members of the village council with a focus on uses of the woodland products. Canonical correlation analysis and pairwise correlation analysis were used to detect significant relationships between the socioeconomic variables of the households and the variables of the collected or used woodland products by the households. Results show that animal husbandry is the most important activity for providing villagers? income. Fuel wood, seeds and ground fodder are collected woodland products in the area. Among the key socioeconomic characteristics of the households, increased educational status and cash incomes from sources other than the woodland are associated with less dependency on the woodland resources, and consumption of energy has a positive correlation with the collection of fuel wood.

Natural radionuclides present in soil as well as certain anthropogenic radionuclides released to the environment are the major contributors to terrestrial outdoor exposures. In the assessment of human exposures from environmental radioactivity, besides the conventional method of soil and vegetation sampling combined with laboratory based analyses of environmental media, the other choice would be field spectrometry which is a rapid, efficient and economical means of identification of radionuclides in the environment. Newly developed high resolution solid state gamma-ray detectors provide a state of art means for such a purpose. However, they are relatively expensive, may not provide the highest intrinsic efficiency possible and their use is complicated by the need for cryogenic cooling of the detector. Scintillation detector spectrometry systems are considered to be capable of yielding satisfactory results particularly for natural background measurements at a fraction of cost. This paper describes a comparative study on application of NaI(Tl) scintillation and HPGe solid state systems for in-situ measurements of 40K, 226Ra, 232Th and 137Cs soil inventories at selected regions on the south coast of Caspian Sea, along with the results from laboratory analyses of collected soil samples in the area. Based on in-situ measurement results and field experience, it is concluded that NaI(Tl) spectrometry system provide satisfactory results which might be even improved by incorporating special spectrum analysis techniques, is relatively less expensive and is operationally easier to carry out than either HPGe system or direct laboratory based analyses of soil samples.