IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2005 | Volume:57 | Issue:4|Papers Count:26

Yazd- Ardakan plain is located in central Iran, between Yazd and Ardakan with an area of about 650,000 hectares. Mean annual rainfall is less than 65 mm. Rainfall distribution is uni-modal with more than 70% of it occurring in winter. Wild plant density varies from 25% to 0. Artemisia sieberi is the prevalent plant species. A major part of Yazd -Ardakan plain is bare land. Topographic conditions, soil erodibility and wind storms have been formed to a big Erg with an area of about 28,560 ha. Several kinds of sand dunes such as:barkhan ,barkhanoid ,sif ,silk ( Linear dune) and ghourd ( Star dune) were diagnosed in this Erg.The highest sand dune is 19 m high and the longest is a bout 7 km wide. Many kinds of abrasion facies are formed in Yazd plain, from pediments (coarse grain plain) to piedmont or bajada (fine grain plain) such as Hamada (Desert pavement, Reg), parabolic shape (ventifact marking on the soil crust), Nebkha ,Rebdoh, Yardang (Kalut), respectively. Although several parts of Yazd Erg and their origin areas have been fixed by different kinds of wind erosion control methods, wind storms still cause some damages to other parts of Yazd- Ardakan plain. According to the recent investigation more than 20,000-m3 dust with less than 100 micron diameter falls down annually in Yazd City with an area of 7000 ha. Horizontal visibility is reduced to less than 6m in stormy days in some parts of Yazd -Ardakan plain. This phenomenon causes car accidents on the main Yazd -Ardakan, road and can cancel airplane flights during the stormy days. At present, it is estimated that wind erosion causes more than 6.82 million $ damages to socio-economic resources in Yazd plain each year. Without a proper and prompt management, we may see more treats and hazards to human life in these areas.

Different methods for simulating catchment response and investigating flow regime in rivers have been developed in recent years. Among them, the deterministic rainfall runoff models as a simplified representation of a complex catchment system can be used to obtain an understanding of a system's performance under specific conditions in either gauged or ungauged catchments. Except in rare cases sufficient measurements of catchment variables are not available in Iran, hence, a physically realistic model, which allows easier estimation of the parameters, along with estimating catchment responses, is needed in practical engineering work.The Soil Dryness Index (SDI) model as a water balance model, originally developed by Mount (1972), was adopted to meet the purposes in this study. The latest version of the model (Kuczera, 1988)was modified and after several structural changes to fit Iranian catchment conditions, was used to simulate the land hydrologic cycle in 8 representative catchments namely Kasilian, Kardeh, Amameh, Lighvan, Kan and Kameh located in different regions of the country.The model was applied to the catchments with daily rainfall, potential evaporation and catchment characteristics as inputs, to estimate runoff, actual evaporation and recharge of groundwater considered as outputs.The results indicated that the adopted model with its corresponding optimum set of parameters was of the capacity to predict runoff values with similar properties to the recorded runoff. A comparison between monthly measured and estimated runoff revealed the coefficient of determination (R2), respectively as: 0.73 (Zarin Detrakht), was 0.63 (Lighvan), 0.5 (Kan), 0.5 (Farsan), 0.5 (Kohrang), 0.47 (Casilian), 0.39 (Amame), 0.34 (Besot). The model assumes catchments as having 4 storage capacities and this could be the main reason for the obtained satisfactory results. The application of the model revealed good results in 6 catchments and therefore can be used as a useful tool for research as well as and design in catchments with similar characteristics elsewhere.

This research is aimed at determining the factors that affect the adoption of soil conservation technologies among farmers executing soil conservation practices in Zarrin Gol watershed, Golestan province. The study is carried out through survey and proportionate stratified random sampling procedure. Two hundred and forty farmers executing soil conservation operations in six villages of mountainous districts of Zarrin Gol watershed were interviewed using questionnaires. The data resulted from this procedure was analyzed through SPSS software. The findings of the study indicate that there is.a significant positive correlation (99%) between the factors of working time period of second- occupational farmers, relative advantage, compatibility, triability, observability of results, complexity of soil conservation operations, total land under management, total land under cultivation, quantity of soil conservation loans, amount of installments, preference for counseling the grey-bearded about preservative operations and the dependent variable of the adoption rate of soil conservations operations. Moreover, there was also a significant and positive correlation (95%) between knowledge of the effects of soil conservation operations, number of training courses the farmer has participated in, amount of information received from radio as well as instructional pamphlets, and the dependent variable of adoption rate of soil conservation procedures. The findings of regression analysis indicate that 60% changes in dependent variable is explainable by independent variable factors of: compatibility of soil conservation operations, total land under ownership ,condition of ownership lands, number of soil conservation loan, relations between soil conservation responsible organizations, access to loan, observability of results, amount of information received from radio and as well as farmer's wife's awareness of the existence of such conservation operations.

Drought which is one of the most injurious and chronic natural disasters, is defined as the continuous and abnormal moisture deficit. The term of continuos means continuation of deficit and the term abnormal means deviation of favorite index of natural condition from the mean. In every drought study four main characteristics are considered: Severity, Duration, Frequency or Return period and Areal Extent The objective of this study was to analyze these characteristics of droughts and to use them in plotting drought maps over Karoon basin. For this purpose, the Standardized Precipitation Index (SPI) as a selected index, was used for an evaluation of drought inside and outside the basin. Records from 29 stations within the same period of 28 years (1972-1999) in 3 time scales of 3, 6 and 12 months were used. After computing drought and wet period time series using the SPI, several characteristics of droughts were considered and areal extent maps of droughts plotted using Arcview software. The result of stationary analysis, while with considering above characteristics show that the least observed SPI and the severest duration due to drought Magnitude has happened in Menj station while Darshahi station has experienced the longest duration as well as the highest frequency during the record period. Drought maps show that southeast of the basin, near Darshahi, Batari, Pataveh, Yasooj, Shahmokhtar and Menj stations has experienced severer drought as compared with the other areas. It seems that this area is potentially more prone to droughts than other sites.

Assessment of relations between rainfall and runoff is an important and complex issue in hydrology In. this respect, much research has been carried out and different empirical methods have been presented to estimate volume and peak discharge of runoff in watershed scale. Since, there is little or in some cases no hydro-climatic data available in Iran, using empirical procedures seems to be the best solution. Among these methods, the Soil Conservation Service (SCS) runoff Curve Number (CN) technique because of flexibility and simplicity is a practical one, which has acquired widespread application all over the world.In the current research, CN was computed in Lighvan watershed located in northwest of Iran using the related watershed factors such as land use, soil hydrologic group as well as vegetation cover and then compared against observed runoff data. The National Engineering Handbook-Section 4 (NEH-4) CN method was compared to show alternate methods for determining CN to investigate their applicability in estimating runoff depth. In S-probability technique frequency values at the 10% and 90% probabilities for maximum soil water retention (S) were then used to determine CN for antecedent moisture conditions (AMC) I and III respectively. Also the mean probability of S determined the CN for AMC-II. In asymptotic method also rainfall-runoff depths were sorted and for each rank-ordered pairs, S was calculated and the CN values computed. The relationship between the calculated CN and rainfall depth was used to determine CN for AMC-II. The comparison showed high accuracy of asymptotic technique in estimating runoff volume as well as peak discharge of the watershed. The NEH-4 CN method is of the lowest accuracy in estimating runoff volume. This should serve as a caution to managers and research workers utilizing CN for hydrologic modeling and application.

Use of recharge basins is one of the methods for artificially recharging groundwater. Selection of suitable sites for artificial recharge is very important and needs to be carried out accurately. Due to presence of various and effective spatial parameters in selection of suitable sites for artificial recharge and a need to review the evaluated factors in relation of one to the other, as well as their changes GIS is a useful system to be employed for spatial data management. In this study it is attempted to select suitable sites for groundwater recharge through recharge basins in Gavbandi watershed southern Iran, using GIS. For site selection, the information items, slope, surface infiltration, alluvial thickness and quality of sediments were investigated and integrated in GIS using Boolean and Fuzzy logics. Satellite images were used to prepare the geomorphologic and land use maps. The results indicated that about %12 of the area is suitable for artificial recharge with suitable sites being located mainly in the alluvial fans and piedmont units.

The domain of growing Lebanon oak covers around 106316 hectares (%24) of northern Zagross rests. Even though forest service in the Organization of Forests and Rangelands considers Zagross forest as protected, yet continuing exploitation as wood and fodder ley local population to meet their basic daily needs is quite usual and the forest service has not so far been able to put an end to this. As is necessary to manage forests with due consideration to people's rights and activities rather than denying them, the forest service has adopted a policy of management in which active participation and cooperation of local people is fully token into account. Considering the new policy along with applying the new regulations, to manage forests as regards timely harvesting as well as reproduction based on stand age structure, collection of information on tree diameter growth seems to be a must and a key part of management.this research was conducted to estimate the diameter growth of the trees growing in Havareh khole forest area to present a model of forest regulation in the father future studies. Thirty four pairs of increment cores of Lebanon oak were randomly selected through line sampling. Also 7 trees were cut to be used for further and more precise measurements. Current annual diameter growth in these trees was measured to be 3.5 mm/year with relative sampling error of 10.7% at 95% confidence level. There made it 12 cases of samples that made it possible to get the precise age of the trees. Based on these measurements age-diameter regression line was developed to help find the age of trees through diameter measurements.

There are two phases involved in any road construction project, namely design and construction operations. In the construction phase, type of materials and the respective strength play an important role in the construction cost as well as in forest road longevity. Some soils, because of unsuitable technical characteristics, Create difficulties in the process of road building. In such cases, reclamation and stabilization of soil must initially be taken into consideration. In order to find out the pro procedure as well as kind and quantity of stabilizers it is needed to carry out studies and make comparisons among options. This is needed to make one able to choose the least cost method in attaining the objective. Soils of Namkhaneh district in KheiroodKenar forest were investigated in this study. A total of 61 samples were taken; soils with little susceptibility every 500 meters while soil with high susceptibility every 250 meters. In a geotechnical lab, the samples were studied and classified according to Granolometry Experiment, which consists of cieving (coarse materials) and hydrometry (fine materials). Through Ate berg limits experiments, liquid limits and plasticity limits were, determined. According to these experiments, soils were classified as SM.ML.CL.CH.In CH soil two subgroups of CHL and CHH (low and high liquid limit) were recognized After classification, density and optimal humidity in each class of soil was determined. The resistance in each soil class was obtained through CBR and plate bearing tests. Soils were mixed with 3,5,7 and 11 percent lime and then percent of optimal humidity was recalculated. This treatment was carried on for 48 hours under standard conditions (500°c). It was concluded that ML, CL, CH and CH soils reach their maximum resistance while mixed with 3, 5,7 and 10 percent lime 10 respectively. Because of their high Strength, MS soils were not tested in this study.

The efficiency of Timberjack C450 wheeled skidder was evaluated using cut-to-length method in Shafarood forests in Guilan province. In this study, the elemental times and effective factors on turn time were identified while 41 turns being studied. The effective factors included skidding distance: volume per turn, percent slope of skid trail, winching number of logs per turn. Tree species were recorded. Main results after data analyses can be summarized as follows:The model of skidding turn time as a dependent variable is a function of the independent variables skidding distance, volume per turn, winching distance, and the number of logs per turn. To production either with or without delays were 10.56 and 13.38 cubic meters per hour respectively. FAD model of machine cost was used being estimated at 290422 rails per hour. Based on this, the production cost with and without delay times were 32995 and 26653 rails per cubic meter respectively: Delay times count the most, next to times taken in either loaded or unloaded travel. The cost of sleidding per turn was linearly related to either of skidding or winching distances, as well as linearly related to increase in volume of log per travel turn.

An inventory of trees citing their different characteristics can be a useful guide in their management, as well as help them grow in a most proper way to shoot the targets of sylviculture and finally a feasible forest enterprise. Knowledge about natural species, which are existing now but may not be naturally available in the future for the next generation is undoubtedly very useful. In Gorazbon district of educational and research forest of Kheiroodkenar of the Faculty of Natural Resources, 116 trees of Ash species were chosen and their necessary characteristics measured and evaluated (Selection Sampling).some results of studying the relationships among the evaluated characteristics are:Among the different models showing the relation between diameter at breast height, and the height the tree the statistical-mathematical equation is a more suitable estimator.ĥ=(d2 /(-4.317+0.833×d+0.0172×d2))+1.30 2-The statistical-mathematical equation between diameter at breast and crown height is: ĉh=2.989+0361×d-0.00228×d2 3-The statistical-mathematical relation of diameter at breast and crown diameter is:ĉd=0.567+0.176×d-0.00072×d24-The relation between diameter at breast and hid coefficient is:ĥ /d=150.1204e-0.014923×d5-The relation between diameter at breast height and stump diameter is:d^=0.397079+0.773406×dst6- Other relations, which have been mentioned and illustrated in the results section of the article.

Fandoghlu forest with an area of 4378 ha is located at the end of Western Elburz mountain Chains-northeast of Ardebil, Iran. It has extra importance due to it's high species diversity as well as it's standings the most valuable natural forest in Ardebil region. As for maintenance, restoration and development of forests, accurate sylvicultural studies in forest stands succession is essential, this study was carried out while 5 broad leaved mixed stands (totally 404 ha) were investigated.In order to study succession, besides stands, structural characteristics (such as composition, layering and regeneration), historical materials including, analysis of Fandoglu natural resources comprehensive plan of 1984, conversations with old local people in the region as well as observation of similar sites in astara region came into consideration.according to this investigation Fagus orientalis has a meaningfull role in the forest stands as well as in their natural regeneration, not admitting the belonging of the site to corylus stands. This survey shows that due to increasing abundance of main species such as Fagus, Carpinus, Quercus, Sorbus and Acer a long with decreasing abundance of pioneer species such as Corylus, Crataegus and Mespilus the existing stands are passing the preliminary levels of succession. At the end, according to this study, it can be concluded that these stands are progressing towards a climax of uneven-aged mixed stands of are passing the preliminary or Quercus castaneifolia.

This study was conducted to determine some of the biological aspects, namely weight, total length, relative gut length (RLG/Index), growth, condition factor, food habits and food selectivity of river loaches, Nemacheilus malapterurus, in Zarringol river, Golestan province, northern Iran. A total of 149 specimens were caught using an Electro-shocker and immediately fixed in 10% formalin. The frequency for males, females and immature was 37.5, 9.3 and 35.5% respectively. Sex ratio was 4:1 (male: female). Statistical means for total length and body weight were significantly different for males and females (P<0.01). Average total length and body weights were 59.07 (14.8); 82.42(28.86); 39.73(6.27) mm; and 1.89 (1.8); 5.31 (4.98); 0.53 (0.21) g for males, females and immature, respectively. Condition factor was 2.6 for females and 1.97 for males. The regression coefficient for tales and females is less than 3 indicating the length to weight growth to be algometric. The low RLG index (RLG<I) shows that N.malapterurus is carnivore. In this study food selectivity (IvIev Index) was mainly for family Blood worm (Chironomidae) with a frequency of 65.3% in the diet.

Density profiles in three types of Iranian made particleboards were assessed through X-ray microdensitometer method. In the studied particleboards the density in surface layer was higher, that in core layer. The density profile in one was symmetric and normal while in the other two it was more asymmetric and also and lessnormal. Hterogeneity was observed in value as well as for longitudinal profiles in these partic1eboards.The modulus of elasticity in particleboard with normal profile is observed to be more than that in the others

The possibility of the use of three chemicals, namelya mix of mono and di ammonium phosphate (50:50), a mix of mono ammonium phosphate and borax (90:10), and a solution of 13% ammonium phosphate as fire retardants in materials used in the construction of gathering halls was studied. Wood (Picea) samples were prepared according to JISA, 322 Standard. To make wood samples fire retarding they were impregnated while employing hot and cold bath as ell as dipping methods. Fire retardation was achieved in stuff and sponge while employing dipping method. Wood samples became the most fire retarding when treated with the mixture mono and di ammonium phosphate, (50:50) in cold and hot bath. These samples exhibited the most physical and mechanical strength when subjected to cmpression forces parallel to grain. Least volumetric contraction was observed in samples treated with ammonium sulphate. Stuff impregnated by mono and di ammonium phosphate were more resistant to fire. Samples impregnated with ammonium sulphate took the longest time to reach the fire point.The resulting Flame lasted least after torch removal from the sample in the case of spongesimpregnated with mono and di ammonium phosphate.

To measure the rate of longitudinal permeability in hornbeam wood to water, 27 sapwood and 27 Heart wood samples of hornbeam species (Carpinus betulus L.) in three diameter classes (25, 50,75 cm) were chosen from one vegetative habitat.By the use of a wood permeability measuring instrument, the flow rate of water in samples was determined while applying constant pressure difference on the two sides of samples. Then, using Darcy's law, the permeability of samples was measured. The variations in flow rate and permeability are shown through curves.The results indicate that, contrary to one of main prerequisites for Darcy's low, the flow rate and permeability continue to decrease with time. This issue can happen when the intravascular micropores are blocked with external materials or air bubbles. The results also indicate that there is not a significant difference in sapwood and heart wood Permeability within different diameter classes, but that there is a significant difference in heartwood and sapwood permeability in each diameter class. The amount of heartwood permeability is approximately 55% less than that in sapwood.

Poplar wood fibers in the form of refining mechanical pulp (RMP) and old corrugated container (ace) in four levels of 10,20,30 and 40 percent as well as three levels of mixing temperatures of 180, 190 and 200 degrees Celsius have been used in wood -fibers/polypropylene composites. Two percent of maleic anhydride (MA) and 0.1 percent of dicumyl peroxide were added to mixture as compatibilizer and initiator respectively. The results indicated that the effect of poplar fibers on impact energy (Izod), tensile strength and modulus, bending strength was higher than acc fibers. It was shown that percent of elongation in composites was reduced by the addition of poplar, wood fiber. The extent of improvement of properties is dependent on the percentage weight of the fibers. Tensile strength, modulus of elasticity, and bending strength increased, whereas elongation and impact energy decreased. Tensile strength, bending modulus and impact, at 190°C mixing temperature increased while elongation at 180°C decreased.

Information regarding forage nutrient value is important in grazing management of rangelands. For an investigation of variation in nutritive quality of forage in different climatic zones as well as in different phonological stages, five species were chosen for the study. Samples were collected randomly and dried for chemical analysis. Dry matter, ash, crude fat, crude fiber, crude energy, crude protein, acid detergent fiber, natural detergent fiber and minerals (Cu, Fe, Zn, Mn, Na, Ca and P) were measured by different analytical methods. Analysis of variance indicated that environmental conditions affect forage quality. Phonological stages caused more variation in forage quality than either climate or species Nutrient qualities in forage in all species decreased from full flower to seed ripening stage. However, variations between either species or climate were not significant. Therefore in grazing management variation of forage quality during growth stage should be taken into account. Based on correlation between investigated factors for classifications of forage quality, measurement of crude protein and acid detergent fiber are more important than the others.

Asafoetida (Ferula assa-foetida L.) is an important medicinal plant belonging to the Apiaceae family. It is a herbaceous, perennial and monocarpic plant. Flowers appear only once during the lifecycle of the plant. The root contains accumulated resin. The resin that can be secreted by incising the root is of medicinal properties. It is used as a vermicide, as well as in treatment of insomnia. This study was carried out in the asafoetida (Ferula assa-foetida L.) rangelands in Khomrout located in Zarand in Kerman province. The main aim of the study was to find out the most suitable method of incision which not only yields the largest amount of resin but also does not damage plant life. To achieve these aims, five incision methods consisting of widthwise (control), one-sided, two-sided, lengthwise as well as composite (mix of one-sided and lengthwise methods) were employed. The statistical design was a complete randomized one with five replications. The results show that incision methods have a significant effect on the resin content as well as the survival of Asafoetid. The average yield of resin in widthwise, two-sided, one-sided, lengthwise and composite method was 62.94, 59.64, 39.08, 19.66 and 42.38g per plant respectively. Percentage of survived plants was 12, 86, 94,76 and 96 percent respectively. There was no significant difference observed between resins in two-sided (59.64 g per plant) and widthwise (62.94 g per plant) incision methods but a significant effect was observed on the percentage of survived plants. The highest survived plant (86%) and the lowest one (12%) appeared in the plots incised through two-sided and widthwise methods respectively. Therefore, according to the obtained results two-sided incision method for asafetida is suitable and recommended.

A knowledge of the Process of change in available carbohydrate reserves in dominant plant species is indispensable in a sound model of range management. Three species of Salsola rigida, Artemisia sieberi and Stipa barbata are the dominant species in the steppe regions in Yazd province. An investigation involving these species was conducted in the range and animal research station of Nir during 2001.Root and shoot in these species were sampled in eight stages from late May to late December. Soluble carbohydrate was determined using Phenol­_ Sulphuric Acid method. Treatments were distributed in a split plot (in time) design. The three species were randomly employed in main plots. Results demonstrated that Stipa barbata shoot had the maximum percentage of soluble carbohydrate as compared to the other two species. This difference was significant between Stipa barbata and Salsola rigida, while Artemisia sieberi stood between these two species.The three species were significantly different for the percentage of root soluble carbohydrate. The percentage of root soluble carbohydrate in Salsola rigida, Artemisia sieberi and Stipa barbata were 1.371, 0.760 and 0.384, respectively. In general, Artemisia sieberi and Salsola rigida contained the maximum soluble carbohydrate during seeding stage, while in Stipa barbata this happened in flowering stage. According to the results, the minimum damage to growth in these species occurs during the mentioned phonological stages. In addition, it was revealed that grazing Stipa barbata is more sensitive to late grazing as compared to the other studied species due to soluble carbohydrate changes during its phonological stages. This It may be one of the main reasons for Stipa barbata extinction in Steppe regions.

The allelopathtic effects of Atriplex canescens on seed germination in Artemisia sieberi was investigated through the present study. Since there was not enough knowledge on allelopathic effects of A. canescens on A. sieberi, thus allelopathic effects were first studied using solid MS medium. Then the allelopathic effects were studied using At. canescens extracts on Ar. sieberi seed germination in a germinator. Therefore, a ten percent weight/volume (W/V) extract from leaves and fruits of A. canescens was prepared. The extract was diluted by adding distilled water to 5, 10, 15, 20 and 25 percent. The effects of the above concentrations, as well as distilled water as control, were studied on seed germination using a completely randomized design (CRD). The treatments were grouped using Duncan test. Results indicated that there were significant differences among the treatments for either germination speed or germination rate (P<1%). Control and the 5% concentration exhibited the highest germination value while 25% lead to the lowest percentages germination.