IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2007 | Volume:60 | Issue:3|Papers Count:38

Because of many problems associated with traditional procedures for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to assemble such information. The first step involved in the application of this approach is the selection of a composite of diagnostic properties which clearly discriminate sediment sources. In this study, it is tried to choose a suitable composite of geochemical elements with the ability to discriminate lithological types in subareas of main subbasin of Pouldasht water spreading station basin, located in Makoo County, West Azarbaijan Province. The lithological maps were prepared, and lithological types as sediment sources were classified in five groups. Totally, 106 samples representing lithological characteristics, including uses, slope steepness and surface and subsurface erosions, were selected. Samples below 63 μm were separated and concentration of 18 geochemical elements was measured. Then, after being assured of the absence of outliers and insubstantial contribution of non-normality and inequality of covariance matrices to the results, the discriminant analysis was used to select the suitable subset of elements from the 18 geochemical elements. In order to eliminate the effects of multicollinearity on the discriminant analysis results, a subset (composite fingerprint) of elements, which enjoys both characteristics of least multicollinearity and highest discriminating power, was selected. The identified subset included 12 elements (Al, Co, Cr, Cu, Na, Zn, Mn, Ni, Pb, Mg, Sb and K) and was able to discriminate and classify over 87.7 percent of soil samples correctly. Meanwhile, all the 18 elements were ranked based on their relative ability to distinguish lithological groups, among which Ni was the most important and As and Sr played the least important role.

Rainfall erosivity is one of the most important factors determining soil erosion. This factor is usually expressed as erosion indices that are based on rainfall characteristics. There are various indices that may be determined in weather stations but determining these indices in other places requires development erosion maps. This research was aimed at developing the rainfall erosion map for the Namak Lake basin. In the first step, weather stations were examined in term of their locations and the quality and type of the data provided by them. Reviewing studies and researches conducted in the world and regarding the limited number of the weather stations equipped with recording rain gauges and other instruments, the modified Fournier index that may be derived from statistics of monthly precipitation was used. For this purpose, the index was computed in 182 the weather stations having records of precipitation over the last 20 years. Minimum, Medium and maximum values of modified Fournier index were obtained 14, 44 and 95 millimeters, respectively. The interpolation methods under consideration consist of TPSS (thin plate smoothing spline) with powers of 2, 3, 4 and 5 and with and without secondary variable; WMA (weighted moving average) with powers of 1, 2, 3 and 4; and ordinary Kriging, and Cokriging. The method of TPSS with power of 2 was found the most suitable. MBE, MAE, RMSE and R2 (determination coefficient of observed and estimated data based on the TPSS method) were -1.21, 4.46, 6.24 millimeters and 0.85, respectively.

Recently, desertification as a great problem threatens many countries all over the world. For evaluation and mapping of desertification many researches have been conducted in other countries leading to regional and local models. This research uses MEDALU, introduced by European Commission in 1999, to investigate desertification in Kashan area. The criteria and indices used in model were re-defined before application, so in the revised model seven criteria and 45 indices were assessed regarding conditions of the aera. These criteria include water resources degradation, wind erosion, water erosion, climate, soil and management factors. Each criterion was assessed based on the selected indices, which resulted in qualitative mapping of each criterion based on selected criteria. Finally, sensitive (susceptibility) map of the area was prepared using geometric average of all criteria. The result indicates desertification in the region has an accelerating trend which may be extended throughout the region in the near future. Regarding the studied criteria, water resources degradation has the highest effect on desertification. This area, excluding urban lands, 196.67 km2 of the area was categorized in the moderate desertification class while 366.04 km2 and 240.21 km2 of the area are prone to high and very high desertification.

In this research, results of analysis of instability hazard of natural slope using a fuzzy logic functions is presented. Fuzzy models, owing to their flexibility in evaluating propositions are more realistic than conventional models. Input datasets used to landslide hazard potential evaluation include slope map, lithology, seismic and rainfall maps. Landslide inventory maps are also used to evaluate output of models. The fuzzy algebraic product operator has an increasing trend and, in other words, because of the multiplication of the membership degree of layers in each pixel, total point tends to zero. Therefore, the high point in output pixels of the map shows its high resolution in revealing the instability of slopes. To compare the output landslide hazard zonation maps two quantitative indicators named density ratio (Dr) and quality sum (Qs) have been used. Based on Qs, output map of the fuzzy algebraic product model has sensitivity near twice of the fuzzy algebraic sum model. Based on (Dr), high hazard classes in above models have more accuracy precision as compared to low hazard classes.

Erosion and sediment production depend on complex factors and parameters. Determining factors and parameters that play the main role in erosion and sediment production in a drainage basin can help better management of catchments and reducing damages caused by erosion and sediment production. In this research, for determining the factors affecting sediment yield, Taleghan Drainage basin was chosen as the subject of study. This drainage basin is located 90 km northwest of Tehran and is one of the main drainage of Sefid-Rood Drainage Basin and plays important role in input of sediments to Sefid-Rood Dam. After determining the parameters influencing sediment yield in four general groups and seventeen subgroups as independent variable, the amount of sediment yield in each sub-catchment was also determined as a dependent variable, and then, using SPSS software and through factorial analysis and performing multiple regression analysis between selected independent variables and the dependent variable, the most suitable statistical relationship between sediment yield of sub-catchment and drainage basin characteristics was obtained. The result of chosen model shows that sediment yield of sub-catchments in Taleghan drainage basin depends on four following factors: The area of agricultural lands (dryland and irrigated farming), sub-catchments area, the total area of prequaternary erodible and semi-erodable formations and relief (topographical features). According to results of the research, the factors influencing erosion and sedimentation in Taleghan drainage basin can be divided into three groups: human, topographical and geological factors.

The optimal allocation of limited resources is one of the most applicable tools in management to achieve maximum benefits. The application of optimization techniques in order to optimally distribute land uses is also one of the strategies in watershed resources management. The present study has been conducted in Brimvand watershed in Kermanshah Province and comprises 9572ha with the aim to maximize benefit from land uses and minimizing wastes based on linear programming solution using simplex method and with the help of ADBASE software package. The net profits as well as standard maps of land use were used as input to the objective and constraint functions. The results of the study, considering all governed constraints, showed that using the proper allocation of land uses, besides reducing resources loss, profit increases by 18.62% which is owing to reduction in rainfed agriculture and increase in the area of orchards. The results of the sensitivity analysis also showed that object function is strongly susceptible to the extent of orchard area.

Flood is a natural phenomenon that inflicts damages and casualties throughout the world every year. For flood hazard zonation and determining the lands on the bank of the Gharachay River, located in the Ramian watershed, that may face flooding, a section of the river with a length of 8.5 km was selected. This length was divided into subsections with respect to morphological and hydraulogical characteristics, and 41 cross sections were chosen. Then, the Cowen method was adopted as the best method to determine the Manning's coefficient. In the next step, flow characteristics and geometrical specifications and the Manning coefficient for each cross section were inputted into the HEC-RAS software program and the water level profile for each return period was computed. Then, the AutoCad software program was employed to draw the flooding hazard zones and determine the flooding area and average depth of floods for all cross sections in various return periods. After determining the average area and depth of flood for hazardous areas, and by using flood damages functions, the amounts of damages in urban and agricultural regions were determined separately. Results of the research show that the amount of damages up to the 50-year return has a mild increasing trend, but after that the rate of damage increases sharply. Therefore, the 50-year return period has been interpreted to be the critical return period for this area.

Suspended sediment transport by rivers is important in water quality of cities and villages fed by certain drainage basins. Therefore determination of effective discharge and its characteristics, which carries the highest amount of sediment in long term, is very important. To determine characteristics of effective discharge, probability density function for water discharge is calculated based on daily discharge data and by multiplying coefficients of sediment rating curves by probability density function, sediment density function is drawn. Then, its return period is calculated by statistical analysis of maximum instantaneous discharge. In this research, the above-mentioned method was employed for six headwater streams of Gorgan Drainage basin, using statistical data of suspended sediment records in the past 13 to 16 years in regions with areas between 13 and 165.5 km2. The results have shown that suspended sediment of effective discharge of the stations is between 0.11 to 75.4 (m3s-1), their average frequencies between 0.07 to 16.5 days per year and their return period ranges from 0.96 to 2.07 with of average 1.45 years. The amount of sediment transported by effective discharge is higher than the amount of sediment transported by other discharges, and varies by 3.7 to 15 percent as compared to yearly-suspended sediment. Furthermore, comparing different stations in terms of specific suspended sediment of effective discharge, it has been shown that Nomal and Pasposhte hydrometric stations have the lowest and largest amounts, respectively. Generally, effective discharge for suspended sediment occurs every year or every two years and carries the highest amount of sediment in subcatchments as compared to other discharges.

Three sub-catchment of Daryachen Namak Drainage Basin, including Khomain, Pole-Doab and Rasin, were chosen as the areas to be studied. By using remote sensing data, land use maps of the chosen subcatchments for years of 1956 and 1995 were prepared by application of ILWIS software and changes in the land use were evaluated quantitatively. Later, based on geological maps and field controls, the map of the susceptibility of geological formations and rocks of each sub-catchment to erosion was prepared. Figures of water discharge and sedimentation in the last 24 years in three hydrometric stations in Khomain, Pol-Doab and Razin as well as precipitation figures were received and variation of sediment yield in the three sub-catchments was determined. In the next stage, sedimentation variations in each subcatchment, along with change in the land use in different periods and with various areas and different levels of sensibility to the erosion of golgoical formations and lithological units were compared. It can be concluded that least land use change and low sensibility of rocks to water erosion belong to Pol-Doab. In spite of low sensibility of existing rocks and formations in Rasin sub-catchment, its sediment yield is high in comparison to two other studied sub-catchments which was found out to be due to excessive land use change. Finally, it was figured out that both use change and sensibility of formations and rocks to erosion significantly contribute to sedimentation while the former has a greater effect on sediment yield.

Reliable estimations of low flow are extremely important for water management in arid and semiarid regions in drought periods. However, selecting reliable methods to determine low flows is difficult, and the lack of hydro-meteorological data as in the selection of a distribution for modeling purpose but also in the estimates of the parameters of a chosen model. In low flow estimation, the common approach for the mitigation of some of these problems is the regionalization of frequency. This study was carried out to evaluate the Hybrid method to estimate low flows in northeast of Iran and compare this method with Index Low-Flow method. At first, low flow series with duration of 7 days were chosen, then the best regional distribution function (Log Pearson Type III) was fitted and low flows value with different return periods were calculated. The region was divided into section based on the results of the cluster analysis, in the Index low flow, and based on area, in the Hybrid method. Then, related regionalized models were determined and compared using trial and error. The results showed that the Hybrid method enjoys higher degree of precision as compared to the Index low flow method, and regarding less error in data resources of the Hybrid method this method is recommended.

Trunk (stem) specifications of the beech trees (Fagus orientalis Lipsky) vary in different sites of Hyrcanian forests. To study the morphology of the trunk of these trees in natural unmanaged Haftkhal forest, 30 sample beech trees in three diameter classes of <50, 51-75 and >75cm were surveyed. For the sample trees, diameter at different levels of stem measured in two ways: a) constant distances from the ground level with 2.5 m intervals, b) relative height levels with coefficients of 0.1 tree height. Criteria used for this research are: diameter at breast height (dbh), tree total height (H), mean of the two crossed crown diameters (C), tree thinness factor (H/dbh), form class, equation of dbh and H, equation of dbh and C, diameter reduction factor (drf), tree form factor (Ft) and trunk form factor (Fs) with volume base and diameter base, ratio of trunk length (h) to H, ratio of volume in different levels of stem (Vs) to tree total volume (Vt), geometric form of the different length of trunk (logs), form similarity of the different trees trunk, effect of the distances mean of adjacent trees on the beech stem specifications and finally, correlation and mathematical equations between the above-mentioned factors. Some of the results are: mean of (H/dbh) is 0.52, (Ft) factor is 0.48, the ratio of (h) to (H) is 0.64. Furthermore, it is found that about 74 percent of the Vt is located in lower half of the (H), the rate of stem similarity vary with the growing stages, and finally, (C) has a high correlation with diameter at breast, mean height and the tree's distance from adjacent trees and (dbh) and (H).

The purpose of this study was to estimate the production rates and the cost of loading with the two machines: GMC and front grapple loader VOLVO BM4500. The results indicated that the most operational delays were caused by the lack of suitable landings, lack of proper log preparation, and scattering of logs. Most of the delays of GMC loaders related to technical reasons since these machines are too old and have been primarily designed as a lorry rather than for working in forests. Though using GMC machines imposes higher loading hourly costs the production rate is lower as compared to the front grapple loader.

There are various methods for classifying phenomena in satellite images. Conventional methods of classification are pixel-based. Satellite images may also be classified using object-based methods. In this method, a group of pixels that form the phenomenon are selected. In order to compare pixel-based and object-based methods in distinguishing forests types, this research was conducted in Forest Research Station of Tehran University in the central Caspian forests. The Landsat 7 ETM+ image was analysed. First, a precise orthorectification was done. Then, enhancement techniques, including PCA, Tesseled cap, and rationing, were employed. In the pixel-based method the Maximum likelihood classifier was used and the forest types classified were pure beech, mixed beech, pure hornbeam, mixed hornbeam, mixed alder, mixed and plantation areas. In object-oriented approach, three classification methods of nearest neighbour, membership function, and an integrating of both methods were used. In each method the best segmentation parameters were applied in order to extract the homogenous area as a forest type. By nearest neighbour method, after segmentation, some objects in each type were selected as training objects. By membership function method, classification was done by three steps and segmentation levels. At each level, forest types hierarchically were extracted by determining the best fuzzy logic and function. The third method (combined of two first methods) was performed by four segmentation and classification levels. To generate a ground truth map of forest general types, a systematic random sampling method with 193 plots with one hectare area was done in the forest. In each plot, forest type was determined by computing tree species frequencies using two methods: total number of each species and, a frequency of each species in 100 thick tree classes. The accuracy assessment of forest type maps showed that the object-oriented classification approach considerably improved the results comparing with pixel-based classification approach (from 25.5% to 44.4%). The study also indicated that the combined nearest neighbour and membership function methods could improve the results over the other techniques.

Influence of sowing depth (3, 8 and 13 cm) and sowing date (December and February) on germination rate of Quercus castaneifolia (C.A.Mey.) acorns was examined. The research was carried out on a sandy-loamy-clay soil in a non-regenerated open area of the plain forest of Noor Natural Resources and Marine Sciences Faculty (north of Iran). The experiment was as factorial trial and completely randomized design at three replications. The data analysis in mid-June revealed that the effect of sowing depth and sowing date and their interaction on germination rate was highly significant (P = 0.000). Irrespective of sowing depth, germination rate was greater in sowing date of February (66.2%) than December (18.2%) (P = 0.000). Irrespective of sowing date, germination rate was greater in sowing depth of 3 cm (51.3%) than 8 cm (42%) and 13 cm (33.3%). The best treatment combination was "February-8 cm" (77.3%), and "February-3 cm" (64%). Maximum seed germination (at 3 cm and 8 cm depths), sown in December and February occurred mostly in mid-June and late May, respectively. Generally, in each record date, germination rate in all sowing depths was higher in sowing date of February than December.

Cheshmehbolbol Box tree Community with an area of 200 hectares is located in the protected part of Livan-Banafshtappeh Forest management plan, within the territory supervised by the Golestan Province Natural Resources General Department. The aim of this research was to identify and introduce ecological groups of trees and shrubs in the habitat. Sampling for this study was based on slope, elevation and tree dominant species. For identification and classification of vegetation covers, 10 grid plots of 225 m2 area (based on minimum area method) for tree-shrub layer were randomly sampled in each preliminary unit. Canopy cover and diameter at the breast height of woody species were measured in 80 plots in the study area. Classification analysis was performed using TWINSPAN. As TWINSPAN analysis based on basal area led to better results as compared to the analysis based on canopy cover, other stages of analysis was carried out based on basal area, and four ecological plant groups were determined in the study area. Similarity indexes of the four ecological groups revealed susceptible difference between them. This index also confirmed the existence of the four distinguished groups. Ordination analysis was performed by DCA in order to detect the floristic composition of ecological groups and samples and the result agreed results of TWINSPAN analysis.

Road construction in forests absorbs huge resources and imposes highest costs on the forest management. Therefore, various choices should be evaluated and the least costly one with highest technical efficiency should be selected. Conventional methods of road planning are slow-moving, time-consuming and uneconomical, therefore, to reduce cost and time of planning; the number of road variants is reduced although it has an adverse effect on planning quality. The objective of this research was to develop a method for planning road networks and technical assessment of the roads by using GIS with respect to the feasibility of transporting wood from forests. Firstly a digital elevation model (DEM) was prepared based on digital topographic maps at the scale of 1:25000 and was used for collecting required data. In the next step, 12 road variants were designed using PEGGER (an extension of Arcview software) and digital contour map, and by taking advantage of GIS possibilities the passing percent of all variants of all gradients and directions were derived. Finally all variants were evaluated from a technical point of view in GIS using TON´KM and a new method called CORRECTED TON´KM and the optimal variant was chosen.

Time study on the skidder recently bought by the Mazandaran Wood and Paper Industries Company was aimed at estimating the amount and cost of machine production in different conditions, management, harvest planning, replacement of new machines and defining new labor systems. Recently ten HSM904 skidders have been bought by Mazandaran Wood and Paper Industries Company. Time study on skidders have been carried out to obtain a mathematical model and to calculate the production cost. Our study shows that the time of traveling depends on skidding distance and the number of logs carried in each travel but there isn't any significant relation between volume and slope and travel time. Because the volume carried by a skidder has been less than the power of machine there isn't any significant relation between volume and travel time. The lack of a significant relation between volume of loading and travel time arise from the fact that the volume of the loading in each time has always been lower than the machine's power. Furthermore, low gradient of skid trail (less than 25%) cannot decrease the machine power significantly. A model for mathematical computation, Y = 1.873 + 0.024494D + 2.499N, was developed and hour production and hour cost were calculated to be 6.53 m3 and is 384803 RLS. Training choker men, modifying dump and cable connection form and driver cabin also substantially improve efficiency, safety and helps better utilization of machine in northern forests of Iran.

In order to find an efficient and careful way of selective logging system, the assortment logging method in a ground skidding system was studied with respect to damage caused to the residual stand.In this research stand damage was determined in three stages:1 – Measuring stand in felling areas (plots) gaps before felling operation2 – Measuring damages after felling operation3 – Measuring winching and skidding damages in primary transportation (from stump to landing).To investigate the effect of damages on residual trees and regeneration in felling areas, winching strips and skid trials, 100% inventory method was employed. Considering the results of felling areas in 27 sample plots showed that 21.77% of trees have been damaged because of felling operation. 84% of damaged trees were Beech, 8.9% Hornbeam and 7.1% other species like Acer, Oak and Alder. Trees with less than 35 cm (d.b.h) diameter suffered damages to the greatest extent. This study showed that the damages to saplings are less serious as compared to other regeneration groups. Evaluation of quality of scars on the trunk of tree stand in winching strips and skid ways with regards to position of scars showed that most scars were present at heights below 1 meter and were mostly deep scars (bark removed and damage to cambium observed). The analyses of damages of regeneration and residual stand across the sides of skidding routes showed that the amount of damages depends on planning of the routes. There were fewer damages in the routes that were better planned. This study showed that designing and specifying skidding routes properly before beginning harvest operations allows planned felling. Tthe evaluation of damage of residual stand was carried out in two type of winching strips. The results showed that damages to the stand in the direction of felling towards skid way is less than the direction of felling opposite the skid way.

Located in intertidle zone, mangrove forests tolerate rough environmental conditions, including floods, hurricanes and hypersalinity, owing to their special adaptations. Undesirable man-made conditions (like erecting huge oil installations, excessive utilization of the forests), will accelerate destroying rate of the forests. Present research is aimed at investigating peroxides enzyme reaction to heavy metals. Mangrove have been observed to possess a tolerance to high levels of heavy metals, yet accumulated metals may induce intracellular biochemical changes that may affect the processes occurring on the surface of organs. In this study, 60 individuals of Avicennia marina in forests located in Bushehr Province were classified based on electrophoretic isoenzymatic variations. Few frequencies of the peroxidase isoenzymes accompanied by the same site conditions and suitable site distances facilitating gene exchange have caused the existence of different isoenzymatic patterns in all populations. From this standpoint, no enzyme difference is observed in various sites. Of each enzymatic group, 2-year old branches of A. marina treated wit oil pollutants (Nickel Chloride, Cadmium Chloride, Lead Nitrate, Mercury Sulfate, oil and gas oil mixture and a mixture of all pollutants) with concentrations as existed actually for a period of 48 hours. Among all treatments, two of them (CdCl2 and oil-gasoline mixture) had the most severe effect on the samples. Among three classes separated by PAGE5, some indicated increasing pattern and some decreasing. As the time of the treatments increase, peroxidase activity increases in some individuals and decreases in some others, indicating different reactions of trees to stresses.

This research, conducted in the mountainous nursery in the north, was aimed at finding the proper seed source with the ability to enhance germination, growth and survival of Caucasian maple (Acer velutinum Boiss.). Seeds were collected in heights at elevation of 400, 1,000, 1,600 and 2,200 m above sea level in Sari forest regions and planted in mountain nursery of Sangdeh (northern Iran) as completely randomized block design with three replications. The results obtained in the first season of growth show that the effect of seed source on germination (P = 0.019) and survival (P = 0.013) was statistically significant, so that germination and survival rates were lower for the seeds collected in altitude of 2,200 m as compared to those in lower elevations (P = 0.011). Height growth of seedlings for seed sources of 400, 1,000 and 1,600 m did not differ significantly but it decreased for that of 2,200 m. Collar diameter growth reduced for seed sources of 1,600 m and 2,200 m. The results also showed that late frost does not have a significant effect on the mortality of seedlings with various seed sources (P = 0.176). Generally, based on results of this research it can be concluded that the seeds obtained from the elevation of 1,000 m (Lamzer forest region) is the best source for the production of seedlings of Acer velutinum as compared to the seeds collected in Lajim and Ashak, though these two locations are closer to the nursery.

In order to examine the effect of additives and as well the injection of CO2 on excelsior cement boards, excelsior produced from poplar (Poplus sp) and the Portland cement type 2, and two additives, CaCl2 (calcium chloride) and Al2(So4)3 (aluminum sulfate) with 3% & 5% concentrations was used. The results showed that the board containing 5% of CaCl2 have better mechanical properties that may be attributed to effective neutralization of inhibitory agents of cement originated from wood and better cement hydration. CO2 injection in mat prior the pressing had negative effect on the board properties which is considered as consequence of chemical reaction between cement and CO2, significant increase in hydration temperature in this stage and presetting of cement before press that result in improper cement bonding. Analyzing physical & mechanical properties of produced boards showed that excelsior-cement boards treated with CaCl2 have acceptable properties and higher bending strength and internal bonding as compared to ordinary excelsior-cement board. Therefore appropriate condition to manufacture these boards is the application of CaCl2 5% as an additive without CO2 injection before pressing the excelsior-cement cake.

Nutritional and economic value of wheat flour necessitates the utilization other potential material such as by-products of pulp and paper industry, especially Kraft lignin, as possible filler-extender in urea formaldehyde resin, in the presence of metal ion catalysts. The variables were the amount of Kraft lignin powder and the type of catalyst. Water absorption and thickness swelling of samples after being submerged in water for 2 and 24 hours, modulus of elasticity and bending strength in parallel and perpendicular to grain and shear strength were evaluated according to AFNOR, ASTM and ISO standards and the results were analyzed. The results of this study show that the water absorption and dimensional stability of the boards examined improve with using 30 percent of lignin Kraft powder in the absence of catalyst and, furthermore, mechanical properties of the boards will improve if 30 percent of lignin Kraft powder is used together with zinc acetate catalyst.

Removing contaminants is the most costly step in recycling waste paper and processing recycled pulp. Adhesive materials are insoluble additives found in the water in recycled papers. If not removed, these adhesive materials may adhere to wet-web, wire, felts, dryer cylinders and even appear in the final product and cause numerous problems. This research considers using two chemicals for removing adhesive materials from corrugated containers coated by paraffin and old corrugated containers covered by coating binders that release adhesive materials. The results show that simple screening could remove large particles of paraffin (the amount of rejects was %3.5 for simple corrugated container but increased to %7 for containers coated with paraffin) but screening was inefficient in removing small particles or adhesive materials. Although agglomerating compounds did not have negative effect on the strength of the handsheets but were not able to improve the efficiency of simple screening significantly. Generally, the addition of sodium hydroxide reduced screen reject in all three types of OCC and improved burst and tear indices. Of course, its effect depends on the type of recycled pulp.

Possibility of using old corrugated container (OCC) in the surface layers of particleboard was investigated in order to improve surface properties of product, decrease adhesive consumption and facilitate the use of lignocellulosic resources. Percentages of OCC, humidity of OCC particles of middle layers, and press time were variables of this study, and the percentage of adhesive in the middle layer, the velocity of press closing, press temperature, density of the board (0.7 g/cm3) and the thickness of the boards (16 mm) were fixed parameters in this study. Results demonstrate that proportion of OCC had the most significant effect on the physical and mechanical properties of particleboards as compared to other factors so that by increasing OCC content from 40 to 60%, bending and shear strength of boards significantly decreased while water absorption and swelling were increased after 2 and 24 hours. Moreover, bending strength and swelling values of boards with 40% OCC were almost equal to those of control samples but their water absorption and swelling was significantly higher than these characteristics in the control samples. However, appearance and surface smoothness obtained was found to be better than those of the control samples.

This study was carried out to investigate papermaking properties comparison of fast growth poplar species (Poulus euramericana) at two growing periods of 8 and 18 years for newsprint production in MWPI. This special poplar, has been selected from Safrabasteh research station in Gilan province. Selected poplar was chipping in MWPI. Based on the results of experimental tests, cooking conditions of 20% chemicals ( based on oven dry wood), cooking temperature of 160oC, L:W = 7 : 1 and cooking time of 90 min for 8 years poplar and 130 min for 18 years was selected in order to obtain pulping yield of about 85%. After chemical treatment of wood chips with Na2SO3 solution the treated chips were defibrated in three stages and bleached by H2O2, refined in PFI mill to freeness of about 300 ml.CSF. Laboratory standard hand sheet with gramage of 60g/m2 were made from the refined pulps. The results show that, in respect to physical and strength properties, the paper from poplar wood were superior to the paper produced from CMP pulp of the normal wood furnish(75% hornbeam + 25% beech ), except in optical property of opacity which has shown some reduction. Therefore, by making necessary changes in cooking conditions, to improve the paper opacity, it may be possible to use poplar ( populus euramericana ) as pure for newsprint production in MWPI. In applying this respect, 8 years growth poplar has more priority.

Utilizing of recycled banknote particles in combination with industrial wood particles in core layer of particleboard was studied. Recycled banknotes were mixed with core wood particles. The amount of added recycled banknote was 10, 20 and 30 percent by dry weight of wood particles. The ratio of core layer to face layer was 70: 30. Urea-formaldehyde was used as binder in manufacturing of boards. The amount of resin was 12 percent in face layer and 10 percent in core layer. Process conditions were as follows: press time, 5 and 7 min; press temperature in sides, 160 and 180oC. Physical and mechanical properties of the boards, including modulus of elasticity, modulus of rupture, internal bond, water absorption and thickness swelling were measured. Results indicated that increasing the amount of recycled banknote had a negative effect on the mechanical properties, especially internal bond, of treated boards in comparison to control samples. However, all mechanical properties of the samples were higher than the values recommended by standards. Concerning physical properties (water absorption and thickness swelling), increasing the ration of recycled banknotes reduced water absorption and thickness swelling after 24 hour of soaking. Increasing press time and press temperature improved all the properties studied. Generally, it can be said that recycled banknotes up to 30 be percent may be used in producing particleboard that are suitable for indoor applications.

The mean value of annual temperature and relative humidity of 33 cities in Azerbaijan, Armenia, Turkmenistan, Afghanistan, Pakistan, Oman, United Arab Emirates, Bahrain, Qatar, Kuwait, Iraq and Turkey were determined using climatic data of the past 11 years. The EMC values were calculated using the Hailwood-Horrobin sorption model and its annual fluctuation, together with temperature and relative humidity, were determined. The results indicated that EMC values in the cities ranged from 5.6% to 15.6%. Comparing annual temperature, relative humidity and EMC curves of these cities and conducting statistical analyses, the cities were classified into five groups with mean EMC values of 6.6, 8.6, 10.6, 12.6 and 14.6 percent. Thus, the results showed that EMC of the cities were below or equal to the allowable moisture content of wood and, wood products and the other hygroscopic materials (leather, textile and related products) in service except Bakoo in Azarbajan (EMC=15.6%). Therefore, if wood and wood products and related Hygroscopic materials are processed within the range of the respective moisture content and exported to the neighbouring countries of Iran, their quality and durability could be guarantied.

Saliferous and gypsiferous aridisols are among the vast extension soils of rangelands in arid and semi-arid regions of Iran. Vegetation cover with low density is representative of special physicochemical characteristics of these soils. The aim of the present study was to identify gypsophilous and halophilic plants and also to investigate plants distribution related to physicochemical characteristics of saliferous and gypsiferous in Eshtehard winter rangelands. Vegetation sampling was conducted in the key area based on randomized-systematic pattern, and data including canopy cover and density along transects in each plot were determined. After determination of plant types, the soil profiles were excavated and soil samples collected. Based on the standard methods, physicochemical characteristics, including soil texture, electrical conductivity in saturated extract, soil reaction, organic carbon content, gypsum and equivalent calcium carbonate percentage, soluble anions and cat ions were determined. Multivariate method of principal component analysis (PCA) was used to analyze the collected data. The results showed that the vegetation distribution pattern was mainly related to soil characteristics such as salinity, texture, chloride, soil reaction, gypsum and gravel percentage.

In this research, in order to determine the nutritional value of important vegetation species in certain climates, samples were selected from among 23 palatable and important plants that generally found in the ranges under consideration. The sampling was performed in two phonological stages in years 2004 and 2005. Then, the samples were chemically analyzed for the determination of their nitrogen and ADF content. The split plat method was used for the statistical analysis of data with respect to the arrangement of randomized complete block design in three replications of 46 treatments in each location. Plant species were taken as main factors and the growth stage was considered as the secondary factor and ranges played the role of replication. The characteristic studied was the forage quality (nutritional value) of the plants in various phonological stages in the course of two growth seasons. Following collecting data, in order to examine changes in forage quality of the species in various phonological stages and as well the mutual effects of the harvest year on the forage quality, the combined variance was analyzed using MSTAT-C software program and mean values were compared based on the Dunken test. Results show that chemical composition of the plants studied varies considerably and the phonological stage affects the forage quality significantly. Statistically, a significant difference between ADF content of the species in various phonological stages was not observed so that the study showed changes in a certain species in the years under consideration follow a single trend. The protein content of the species in different phonological stages of the harvest years also varied significantly.

Sagebrush (Artemisia spp.) is one of the most dominant plant genera in Khorassan rangelands. Because of the small size of floret, seed ripening time should be determined carefully. In order to determine the optimal time for collecting seeds of this plant, a research began in ten areas in the north, center and south of Khorassan Province that lasted 2.5 years. These areas included Bojnord( Ghorkhod, Baghlegh and Biou), Mashhad (Kordian), Torbat-e-Jam (Cheshmegol), Sabzevar (Ghods, Ghaleh Nordab) and Gonabad (Bimorgh, Ostad and Bajestan). At first, Sagebrush (Artemisia spp.) species was identified in Torbat-e-Jam, Sabzevar and Gonabad (A. sieberi), Ghourkhod and Baghlagh (A. diffusa), Bio (A. kopetdaghensis), Kordian (A. aucheri). The seeds were collected from the time of setting to shedding time at ten-day intervals over two years. Flowering was also studied in the first year. This experiment was conducted as a factorial design with the aim to find the role of harvesting regions and dates and their interaction effects on determining the optical date of seed harvest. The Results showed that all species enter the stage of flowering in October and seeds are formed until mid-November. Up to early December seed ripening occurs and seed shedding begins in all species, excluding A. sieberi, up to the end of January. On average, the fertile florets in each capitol amounted to 22%, and the rest were sterile. The analysis of variance also showed there is a significant difference due to various regions and dates of harvest (P < 0.01). Furthermore, the percentage of seed germination significantly varied depending on the site and date of harvest. However, almost in all regions, the percentage of germination in last dates of harvest was more that this percentage on early dates by 30%. In this connection, possible shedding of the seeds at the time of harvest is an important factor and attention should not be paid only to viability. Results of this research recommends optimum times for seed harvest on each site were as follows: cheshmeh gol, Beymorgh, Ostad, Ghods, Nordab and Kordian Dec. (5-15), Ghorkhod (Nov. 25- Dec. 5), Baglegh and Bajestan Dec. (1-10). Seeds collected from Sabzevar had maximum germination percentage (p< 0.05). The results suggest that seed collection may be delayed to let seeds matured completely before seed shattering.