IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2007 | Volume:59 | Issue:4|Papers Count:26

In order to determine the source and critical areas of wind Erosion, Sistan Plain, IRIFR-E.A method was applied. According to geomorphologicals investigations, the studied area consists of the following two main units namely: Pediment with 1 type and 11 geomorphological facies and playa with 2 types that includes & geomorphological facies. On the basis of sediment facies in piedmont were divided into 2 groups. Seven Facies (1-3-2, 3-3-2, 5-3-2, 8-3-2, 9-3-2, and 2-3-10) with sediment delivery of 6000-15000 tons/km²/y catagorized in first group while second group consisting of 4 facies (2-3-4,2-3-6,7-3-2,2-3-11) with 500-1500 tons/km²/y sediment delivery. According to calculations the mean sediment delivery of piedmont (fine grain size) is about 12500-48000 ton/km²/y. In playa unit, four facies (1-1-3,2-1-3,2-2-3 and 3-2-3) bear 1500-6000 tons/km²/y sediment load and the other facies carry 500-1500 tons/km²/y, total sediment load consisting 8000-30000 tons/km²/y. Using the relationship between sediment grain diameter (D) and transport distansce in 18 cases, it was shown that in 2 samples transport distance is 5-50 km while in the other samples 20 to 50 km. Therefore the source of sediment is far from the sedimentation area, most sediments having been transported from Afganestan. Dominant and erosive winds in the study area are from North and NW (345-360 N). Also, it becomes evident that during the 6-year period of drought (1997-2003), the erosive winds have carried a consi derable amount of sand especially during the summer and spring seasons. The results of the research show the existence of a close relationship between source areas and deposition regions.

Yazd –Ardakan plain is stormy and one of the sensitive areas to wind erosion in Iran. Since 1988 wind sediment discharge has been being measured in this plain. In 2002 for the first time national project of constructing stations to measure wind erosion sediment was performed in Yazd plain. In order to measure sediment discharge, two permanent and five temporary stations were estabilished in Yazd plain. Samples were taken. Ten-day intervals or after severe storms. In order to analyze and interpolate sediment discharge and determine Iso sand flow map, ordinary Criging method was used by Surfer.8 software. To combine obtained data and mapping, ILWIS software was employed. Results showed that in some parts of Yazd plain, especially near sand dunes, discharge of transported sediment was more than in the other parts and increased to more than 1750 kg in width of one meter per year. Amount of sediment yield decreased to less than 50 kg /yr, per unit of width from a fine-grained plain (flood plain) coarse-grained plain (pediment). Also results indicated that the main direction of transported sediment was from west- southwest, while the prevailing winds and some storms came from northwest-west. There for, the orientation of the Iso sand flow is from NW to SE. Maximum sediment yield was transported towards the end of spring and beginning of summer, especially April to mid June. Analysis of altitudinal distribution of saltation sediments showed that 85% of sediment were transported in a height of less than 50 cm, 12% between the 50-100cm and less than 5% at above 100cm heights.

This study describes a pure sediment comparison evaluated in a survey of effective factors on erosion and sedimentation of Baba-Ahmadi watershed basin, using EPM and MPSIAC models. The selected watershed basin for this study was 37000 ha, that is one of the typical regions in Khuzestan province with respect to geological structure diversity, as well as problems like flood, water shortage, erosion and sediment. According to geomorphological investigation of the study area, 2 units, 15 types, 9 faces, 75 primary geomorphological units and 198 work units were distinguished and separated. Evaluation of effective factors on erosion and basin sedimentation in any work unit was carried out by using MPSIAC and EPM experimental methods. Also with contemplating this matter that slope and surface runoff water increase not seriously affect sediment production of structures or resistant rocks, the pure sediment of this basin was investigated in two cases, with contemplating the area of work units with or without resistant structure. The results showed that in spread of any work unit, rock nature is the manifest factor for resistance to erosion and this matter covers all faces. Also investigating on pure sediment of the watershed basin showed that on slope, the pure sediment of watershed basin was 18.54 ton/ha/year and after omitting the effect of these factors on work units with resistant structure decreased to 12.12 ton/ha/year.

There are various statistical and experimental methods to estimate flood discharge. Acceptability, and an assurance of the results necessitates considering limitations, as well as environmental and hydrological conditions. In this research it is tried to analyze the floods in west of Mazandaran while considering a study of area separation into monotone hydrological units using such different statistical methods as: Index flood, Correlation equation series and Correlation equation method as well as proportions average. Finally, and according to the obtained results, the best regional relations of floods in each monotone unit were determined. The results show that correlation equations series and correlation equations with proportions average are fit to be used in analyzing rivers with rainy-snowy flow regimes and snow-rainy regimes, respectively. In rivers with rainy flow regime, Index flood method is determined as the most appropriate way to analyze the flood.

Two non-regenerated beech (Fagus orientalis Lipsky) gaps of 200 and 700 m2, conducted respectively through single-tree selection system and group-tree selection system, together with a clear-cut area (~10000 m2) were investigated in north Iran. In each area, following a cleaning up of ground vegetation, wild (natural) beech seedlings, Taken out from the neighboring stand, were planted in four plots of 3 ´3m. The results, at the end of the fourth growing period, revealed that survival rate was greater in areas of single-tree selection (63%) than either in group-tree selection (39%) or clearcutting (47%). Collar diameter (between 10.6 and 11.1 mm) did not significantly differ in the three experimental areas. Seedling heights were 78.7, 71.4, and 66.4 cm, respectively in areas conducted by the methods of single-tree selection, group-tree selection and clear-cutting, but there was no significant difference observed of this term among trees in the three areas. Through this investigation and after the fourth year it was deduced that beech wilding, provided from the adjacent stands, can be proposed for restoration of plantation in the non-regenerated gaps. Plantation of beech can be recommended in the non-regenerated gaps of group-tree selection (700 m2), even-though the herbal vegetation is not controlled in early years. Natural regeneration of beech, instead of its plantation, can also be advised in gaps of single-tree selection method. Longer periods of investigation are needed to recommend beech plantation in clear-cutting areas.

This research was carried out in Doveyse Forest with an area of 660 hectares, located in north-east of Marivan Township, Kurdistan province. One hundred and three plots were established using a systematic random rectangular grid with sides of 150´300m. Quantitative parameters of oak stands, coppicing situation of oaks and plant cover were noted in the plots. Based on plant ecological groups' map and physiographical factors, site homogenious units were determined and then soil and litter samples taken from these units. The effect of physiographical factors including altitude, slope aspect and slope percent, some of the most important edaphical factors (totally 19 factors) and quantitative parameters of oak stands (totally 15 parameters) were analyzed using PCA. The results indicated that the most important factors in non-coppicing of Oak manna tree (Quercus persica) were pest damage and grazing. Phosphorous content in litter is the most determining factor in non-coppicing of Gall oak (Q. infectoria) while coppicing of Lebanon oak (Q. libani) is strongly affected with soil pH as well as by litter pH. In addition, coppicing of both Gall and Lebanon oaks decreases with increase in altitude.

In this investigation, HyMap data cube acquired in 1998 over a small forest area in central part of Switzerland was analyzed and evaluated. The HyMap sensor is a 128-channel high-resolution airborne imaging spectrometer that covers the wavelength from 450 nm to 2480 nm. Its pixel size is approximately 7.5 meters. The image has been acquired from 3000m above the earth surface. The research forest-site is a heterogeneous mixture of coniferous and deciduous species. Initially the HyMap data was evaluated qualitatively. Signal to Noise Ratios were very high except in 6 channels. Image orthorectification was performed with parametric method using a digital elevation model and navigation parameters. The resulted RMSE was less than 4 meters. The image was atmospherically corrected using ATCOR-A routine. In order to classify the forest according to mixture-grade of coniferous and deciduous, linear unmixing method was employed. The image based end member collection approach was used to derive the spectra for selected end members (pure coniferous, pure deciduous, clear cutting and shadow). It was performed using air photos and fieldwork. The fraction components derived from the unmixing model were compared with CIR-air photos at a scale of 1:9000. The results showed that the potential of hyperspecral HyMap data and linear unmixing models are very high (95%) for forest classification purposes. Since the spectral mixing is actually non-linear, it is not easy to determine thresholds to classify the abundance images, which are derived from linear unmixing models. Therefore it is necessary to further research for appropriate methods.

To prepare a comprehensive plan for the northern forests of Iran, the precise quantitative and qualitative information are required. In this regard, forest mapping is one of the first steps. The traditional methods of forest mapping (e.g. aerial photo interpretation) in large areas are costly in terms of time and money spent. In contrast, satellite data benefit from a great potential in decreasing fieldwork and consequently reducing the cost of forest data acquisition. In this study the potential of Landsat7 data for forest mapping was evaluated. The study was performed in an area covered by a sheet of 1:25000 topographic map in forest of Babol in Mazandran Province. To do this, Landsat7 ETM+ image acquired on July 30, 2001 was evaluated. Due to the existence of plenty of residential units, the study area is mostly degraded. The evaluation of image quality illustrated less than ±1DN stripping distortion in the ETM 2, 4, 5 bands. There were also duplicate scan lines and sweep (less than 1 pixel) distortion in all spectral bands. Orthorectification was implemented using ephemeris data and a digital elevation model. Several image enhancements such as spectral ratioing, PCA and tasseled cap transformation were performed. The panchromatic band was fused with the other spectral bands utilizing color space transformation and spectral response methods. In order to assess the accuracy of the classified image, a sample ground truth map was prepared through fieldwork considering 18 sample plots (360´360m). Image classification was performed applying automatic and hybrid (digital and visual) classification procedures. In order to classify images, maximum likelihood classifier was applied using training set, prepared through fieldwork. Overall accuracy of resulted forest map in comparison with the ground truth was equal to 94.56%. This map was vectorized to accomplish hybrid interpretation. It was then edited based on various color composites, fused images and ancillary data such as slope, aspect, hillshading images and additional information obtained from fieldwork operation. In this case the overall accuracy of the forest map was equal to 96.39%. This research indicates the high potential of Landsat 7 data for forest mapping in such mountainous and fragmented forests.

In a natural ecosystem, vegetation elements of similar ecological needs constitute ecological groups. In fact, through distinguishing different ecological groups, the differences among environmental variables in various sites can be realized. The aim of this research, done in University of Tehran ’s educational – research forest located in Kheiroudkenar forest – Noshahr, was to explore ecological groups and their relationship with soil characteristics. In order to determine plot (releve) area, minimal area method was employed. To study vegetation cover, 151 plots of 400 m2 area were collected according to Braun- Blanquet combinational method. Following data collection, plant community was separated and classified using Two Way Indicator Species Analysis (TWINSPAN), differential species being indicated in each group. Based on ecological groups and the presence of differential species, 36 points were assigned to introduce physical and chemical characteristics of soil, and the resulting sample were analyzed. In order to analyze soil characteristics in relation to vegetation cover changes, multi – variable analysis, e.g. principal components analysis (PCA) was exploited. The results illustrated that the first ecological group, namely Ruscus hyrcanus, and second group including Asperula odorata, Viola odorata, Hypericum androsaemum, Dryoptris filix-mass, were related to soil chemical properties. The third group with Oplismenus undulatifolia, Cyclamen caucasicum, along with the fourth group, including Mespilus germanica, Rumex sanguineus, Solanum kisereitzcki were mainly in relation to physical properties. Also, it was found that soil fertility in the first and second groups is more suitable and higher than in the others.

The seminal plasma composition including ionic content (mM L-1) and osmolality (mOsmol Kg-1), as well as their physiological correlations were studied in Acipenser persicus subjected to different stripping frequencies (three times at intervals of 12h after spermiation). The semen of 9 broodstocks was collected by hand stripping 24 hours after induction of spermiation through intramuscular injection of sturgeon pituitary extract. Average values of osmolality, Na+, K+, Cl-, Ca2+ and Mg2+ were 82.56 ± 8.1, 62.44 ± 6.82, 6.92 ± 0.88, 21.11 ± 5.41, 0.79 ± 0.03 and 0.51 ± 0.03 respectively. The osmolality of seminal plasma at the first stripping was higher than those at the second and third stripping (T-test, P<0.05). The concentrations of monovalent ions were higher than those of divalent ones. (T-test, P<0.001). Changes of Mg2+, Cl-, and Na+ were not the same as changes of other ions and osmolality, i.e., the concentrations decreased at second but increased at the third stripping. However, there were no significant differences observed between ion concentrations at different strippings (T-test, P>0.05).

In this research work the identification of fatty acids from fresh and frozen tissues of Persian sturgeon (Acipenser persicus) and their changes during cold storage after extraction and methylation of the lipids by gas chromatography (Model: Shimadzo-14 Japan) was performed. The results showed, that the amounts of unsaturated fatty acids in fresh and frozen samples were 88.95% and 79.63% respectively. In fresh tissues the percentage of the Oleic, Linoleic, Alpha-Linolenic, Icosapantanoic and Docosahexanoic were 45.11%, 3.59%, 2.80%, 4.75% and 2.21% accordingly. Among these unsaturated fatty acids the amount of Omega-3 was 11.04% after twelve month of cold storage, there was a general reduction in lipid content in both fresh and frozen samples. This reduction also can be seen in some of the fatty acids such as oleic and alphalinolenic acid. These fatty acids decreased from 45.11 to 40.27 and 2.80 to 1.65% respectively. Also in the fresh samples the between omega-3 to omega-6 fatty acids found to be 1.64. These results were subjected to the test of Tukay and variance analysis. The results were significant at a level of 95%. Thus one can conclude that the cold storage of Persian sturgeon should not exceed 12 months.

Noise pollution was measured in the city of Yazd. Ghiyam avenue was chosen as control in which measurement station in different places locations as well as different days of the week were selected. In 2003, 10 streets were selected where noise pollution was assessed. Results indicated a significant difference (P<0.01) between the two points of the control street (i.e., beginning and the middle part of the same street). Of study in the days of the week only Friday was significantly different (P<0.01) from the rest of the week. There is a positive correlation between the number of vehicles and equivalent sound level in sampling region (P<0/01). The lowest equivalent sound level belongs to Timsar-fallahi street with 74/2 dB (A) while the highest to Ayatollah Kashani with 77/9 dB (A). Correlation between equivalent sound level and the number of vehicles in the 10 study points was not significant (P>0.05). All 10 study points exhibited a higher noise pollution level than the standard level prevailing in Iran.

In this research, Neutral Sulfite Semichemical (NSSC) pulping of Khorasan wheat straw was investigated. Prior to pulping, fiber dimensions of wheat straw were measured, and chemical composition determined by using TAPPI standard methods. Pulping conditions were as follows: Pulping temperature of 2 levels (165oC, 175oC), pulping time of 3 levels (20, 30 and 40 minutes) and sodium sulfite charge at 3 levels (12, 14, 16%). In all cooks, Na2So3 to Na2Co3 ratio was 2:1. Following the cooking phase, primary defibration was done, using a laboratory refiner. At the end of pulping, properties such as yield (after cooking), screened yield and residual lignin were determined. Then, among different pulps, some treatments were chosen for production of hand sheets and measurement of physical and strength properties. Initial freeness measurement of these pulps indicated that increasing sodium sulfite charge and pulping temperature decreases freeness. As to burst index and fold endurance, increasing temperature and sodium sulfite charge increased these strengths significantly, while concerning the other two properties of tear index and breaking length, These variable factors had no significant effect on them. A comparison of all results revealed that, treatment of (175oC, 30 min, 16% sodium sulfite) can be chosen as the optimum condition of (NSSC) pulping of wheat straw for corrugated medium production.

In this research, specific modulus of elasticity and two shear moduli of Cupressus arizonica wood from pith to bark were investigated. Sampling was done, and samples provided from plantations in faculty of natural resources, University of Tehran, Karaj. Physical, chemical and mechanical specimens were prepared from four different locations from pith to bark, in accordance with ISO International and TAPPI test method. For specific modulus of elasticity and shear moduli measurements, the NDT method was "Free vibration on free-free bar". Correlations between these moduli and ring-width, specific gravity and extractives content were studied. Results showed that specific modulus of elasticity decreases significantly from pith to bark and also there exists a significant correlation between this property and ring-width. There were no significant differences observed between shear moduli from pith to bark, but radial shear modulus did have a significant correlation with specific gravity.

Pulp and paper production from non-wood fiber especially from agricultural residues, is accompanied by serious global challenges. Utilization of CEH bleaching sequence on non-wood chemical pulps not only causes serious environmental concerns, but also reduces the possibility of closed mill water circulation. Therefore the application of TCF bleaching (O/Q/OP sequence) on wheat straw soda pulp was investigated. Two application periods (90 and 150 minutes), sodium hydroxide variation of between 1-4.5% and consistency of 8, 10, 12, 14 and 16% were investigated in oxygen delignification stage. Bleaching with H2O2/O2 was studied in two stages. In stage 1, the influence of H2O2 variation (1-4%) and in stage 2, the application of DTPMPA, MgSO4, Na2Si2O3 along with two time periods of 90 and 120 minutes were studied at a constant charge of 4% H2O2. Statistical analysis revealed that the effect of NaOH, temperature and consistency in oxygen delignification on kappa number, viscosity and brightness was significant at 1% level, and an application of one percent NaOH for 90 minutes caused 43% reduction in lignin content. The effect of H2O2 charge, temperature and various additives in OP stage is statistically significant. The results of this stage indicate that if sodium silicate is applied, brightness can reach values higher than 80 %ISO while the use up of H2O2 being significantly reduced. The application of this compound must be at a minimum level of 2%. Strength properties of unbleached and TCF bleached pulps indicate that TCF bleaching was conducted selectively and the strength of TCF bleached pulp is superior to CEH bleached one. Finally the results indicate that the brightness and strength properties of O/Q/OP bleached wheat straw soda pulp are superior to CEH while the AOX of bleaching effluent is also kept at zero level.

Money paper is one of the moist tolerant kinds of papers along with other kinds of bank document papers, about 1000 ton/year of which is at disposal in IRAN. Research in this field not only clears the way to recycling of this kind of paper but also leads to other moist resistant papers recycling. The results of this research indicated that, preparation of pulp from money paper while using usual methods is impossible. Recycling of this kind of paper needs acidic pretreatment (pH=3) of 4 hour duration in ambient conditions and a second stage treatment (pH=3) of 1.5 hour treatment time in 95oC. Screen yeild of pulp after the two-stage acidic treatments was about 67% and the amount of acid consumed 1% of the waste money paper. Deinking of the pulp prepared through acidic treatment showed that there appears no change in pulp brightness. This shows that no hydrolysis takes place on the ink and ink can not be seprated from fiber surface through acid treatment. However, alkaline treatment of the pulp preapared through acid treatment causes breakdown of ink. Pulp brightness after alkaline treatment of 3% NaOH (dry pulp) and, at 95°C with a duration of 2 hours increases from 57% to 75% ISO.

Small diameter timber (SDT) have 5-10 cm diameter and there are many of them in Iran and all over the world. SDP are utilizing in wood product industries. Library information collected from five Iranian organizations and data processing were conducted on the information. Statistical analysis and Mann-Whitney U test are used on the questionnaire. The result of Forest products data and forestation area and also questionnaire analysis and literature review showed that there is a lack of SDP and wood products demand increased in Iran. Wood products insufficiency during the study (11 year) and also annual usual imports cause to compensate wood products lack equal to $200 million in 2003. The factory units have SDP lacked because they facing with poplar plantation unsuitable distribution. Statistical test and analysis showed that is vacillation, problem and situation SDP marketing similar to wood products marketing. To lean on import cause to changing price severely and external competitors will replace internal products.

We investigated the effect of 19 years of grazing exclosure on production, vegetation cover and species composition in a region located in the southern part of Zanjan Township. The Headquarters of Natural Resources Office of Zanjan has exclosed the mentioned area since 1985. Four transects within the exclosure and another 4 transects, each with 30 m length in the vicinity of the exclosure had been established. The sampling method was a Randomized Systematic one comprised of 16 plots, each of 1 m2 in area. Annual growths of vegetation cover were clipped and weighed for the production to be calculated. In comparison to non-exclosure area the decreasing palatable plant composition increased (280%) while increasing and invading plants decreased. The production within the exclosed area was twice that in non-exclosure area.

Bagheshad is a part of Khojir national park with an area of 2310 hectares. It is located 22 kilometers east of Tehran, south of Haraz Highway. Its geographical position is 35o36’41” to 35o39’33” N, and 51o40’29” to 51o46’22”E. In this research the vegetation cover of Bagheshad region was studied based on Braun-Blanquet method. Main and minor plant combinations were determined based on physionomic factors, and then in each, association units were differentiated on the basis of floristic and ecological factors. Area of plot in association units was found using minimal area method. Finally a number of 85 plots were gathered in the whole region. Information recorded in each plot included abundance –dominance and sociability of plant spices. The phytosociologic data were analyzed through ordination and classification methods using Anaphyto Software. Because of existence of different association units in the region partial analysis was done following primary analysis. Then table of plant associations was made using conclusion resulted from analyses of plots and plant species. Finally a number of 9 plant associations and 6 plant sub- associations were distinguished in the area. Map of plant associations was prepared after determining boundaries of plant associations using Arcview ver 3.1 software.

Mechanical resistance, infiltration and moisture content of soil are some of the important parameters that affect plant cover composition in rangelands. The effects of different livestock grazing intensities on plant cover composition, mechanical resistance, infiltration and moisture content of soil in reference (control), moderate and heavily grazed areas located in Savojbolagh (Iran) rangeland was investigated during years 2004-2005.Results showed spatially different mechanical resistance; mechanical resistance was the highest in heavily grazed areas (1085.3kpa), while lowest in reference area (717kpa) and it was higher for the depth 15-30 Cm as compared to 0-15 cm. There was a trend if increasing soil mechanical resistance observed as the grazing period increased. The average soil mechanical resistance increased from 850.2 Kpa at the beginning to 910.4 Kpa at the end of the grazing period. Soil moisture content followed a decreasing trend from control to heavily grazed areas while a reverse trend was observed in moisture content from 0-15 cm to 15-30 cm soil depth. There were significant differences observed in water infiltration rate among different grazing intensities. Infiltration rate decreased from control to heavily grazed area by 3.7, 3.2 and 2.3 mm/min for control, moderately and heavily grazed, respectively. As the grazing intensity increased the gramineae plants, (43.7%) bushes (51.8%) decreased while forbs increased (26.5%) in plant composition in heavily grazed area, as compared to reference. The vegetative plant cover in heavily grazed area is finally comprised of invader forb species such as Rosa harmala, Rosa persica, Ceratocarpus sp which clearly indicates the destructive effect of heavy grazing on plant community and rangeland productive capacity.

Gum tragacanth is considered as one of the economically important byproducts of related rangeland ecosystems in Central Zagross region of Iran. However, there is not an appropriate method available for ecological evaluation of tragacanth habitats. The objective of this research is to determine proper evaluating indices for habitat of Astragalus gossypinus Fischer. and A. verus Oliver. Therefore, based on the determined indices, different habitats could be classified and evaluated in view of their potentiality as well as utilization. This research has been undertaken on 15 randomly selected rangeland sites, located in the above mentioned habitats in Isfahan Province. Rangeland sites were indicative of poor to good quality and quantity in view of Astragal species condition and production. Most important ecological characteristics of rangelands were determined by the following criteria: climate, soil, physiography and vegetation. To classify rangeland sites, cluster analysis was employed for determining the most effective habitat indices, then regression analysis being performed based upon cluster analysis results. According to dendrogram obtained from cluster analysis, 15 rangeland sites were separated into 4 groups by 12 environmental factors and in a similarity level of 88 percent. From among the total incorporated variables, drought period, organic matter, gravel (in case of Astragalus gossypinus) and total canopy cover, shrub height, freezing period, site slope, De Martonne aridity index as well as, cation exchange capacity (in case of A.verus) displayed the effective roles on tragacanth product. For Astragalus gossypinus product, organic matter was indicated to be of a high relative importantce. Total canopy cover and freezing period showed maximum relative importance while site slope and shrub height showed a lower relative importance for A. verus. Suggested models for Astragal species estimate the Gum product at a 0.05 significance level, and in an appropriate manner.