Year:2006 | Volume:18 | Issue:4 (69 IN NATURAL RESOURCES) |Papers Count:16

The semi-arid regions of Iran are obviously characterized by animal grazing. The flock movement takes place according to the availability of forage and water following some traditional habits. On the other hand, due to the escalation of population, much of the marginal rangelands are brought under cultivation. This has led to disregard of grazing patterns, and has also led to upland areas to be degraded. In order to recognize relationship between rangeland condition, soil properties and flock movement in rangelands, a study was conducted in the rangelands of Namrood catchments locating in north-east of Tehran, Iran. Accordingly, in order to study soil properties, geopolitical approach based on the interpretation of aerial photographs, landsat TM images, topographic maps and field surveys was applied. Vegetation cover and its status was assessed using NDVI index and range condition was studied based on the four-factor method (present by FAO) and soil degradation maps were modified from the GLASOD soil degradation map. Results of the study were shown that most of rangelands in mountains and hill land are in good to medium condition, while there are also some rangelands with poor condition (mostly in dominated by piedmont). The human disturbance in some of these units is so high that original plant communities have been completely destroyed and invader species have been substituted. Field observations were also showed that human impact (i.e. over grazing and over intensive wood refuel gathering and shrub cutting) has contributed significantly in the changes of range condition. Based on the results of the conducted research study, it can be concluded that there is significant relationship between rangeland condition, land form, soil properties and flock movement. It therefore is essential to plan to match stocking and destocking of rangelands on the basis of spatial and temporal conditions. This plan can lead to improve the grazing condition and to control soil degradation of rangelands by soil erosion.

The black alder (Alnus glutinosa (L) geartn . subsp . barbata) is one of the important and rapid growth species as a pioneer in wetland areas. It has power to fixing soil Nitrogen with over biomass production in the wood cultivation and various application in short rotation industry. Alnus genus is located from 25 southern to 70 northern altitude in Europe antil 2800 height from the sea level in cold Meditraneh climate (mainly in wet floodplain Hidromoroph and wet soil). This project was performed in Gisum areas between 49° 8' and 49° 5' length geographic and 37° 23' arid 37° 30' width geographic which has been located in Talcsh city. This project were randomly conducted in four blocks (seeding method, coppice method seeding and coppice method and plantation) and three replication of 18 years Alnus of forest. The results show That treatments had not meaningful difference in volume production, basal area of stand 1.30 cm and the number of trees with each other. We can perform each of these four ways for black alder for producing wood in flooe plain lands. This kind with an average 997.6 tree in hectar, diameter average 18.9, height average 17.3 cm , average basal area of stand 24.7 in hectar volume growth auerage 12.9 Silve in hectar in a year was studied.

Weathering is one of the important initial processes for erosion, formation of clastic sediments and formation of detrital sedimentary rocks. We have not any out standing study in macro and micro scale in Iran. On the other hand, in the limited study related to weathering, time and place scale, effective factors and mechanism are not considered very much. In this article we rewiev many usual methods for classification and evaluation based on Viles, professor of Oxford University, supposed method. We consider geologic, climatic, hydrologic, and organic factors in the creation of weathering process, time and place scale in the formation of the weathering features of sandstone in Shemshak formation rocks in Ziarat watershed basin. This method is very useful in weathering of rocks but we have some limitations that one of them is the use of modem techniques and equipments for the study of details of weathering in different scale in our country. Results shown that we have at least 6 types of II types of weathering features in Viles classification method with different variation in study area. Two types completely weathering and very weathering rocks with weathering degree 4 and 5, include 25 and 32 percent of the frequency of 6 studying groups, respectively, in compare with rocks weathering in engineering geology method cover the half of the sandstone of Shemshak in Ziarat watershed basin. So, with test and apply Viles method in different climate and rock groups, we can adopt it in Iran.

Laboratory experiments are required to carried out hydraulic analysis in rock fill and stone porous structures. Many scientists have released various formula on the base of less works. They presented relationships between characteristics of porous media and loss of energy. Those relations are divided in 3 groups: 1) Binominal Forchheimer, 2) Wilkins formula and 3) Linquists simulation [σ]. The second includes simplest Relation between flow velocity (Vv) with flow gradient (i). In the present work, a relation has been developed based on Wilkin formula as well as many laboratory tests on relative crushed and non-crushed stone media. According to these relations if the mean diameter and standard deviation of stones are known, the designer can select appropriate relationship between velocity and gradient. The results show that the correlation coefficient and significance level are 0.993 and 0.001 respectively.

Effects of canopy densities on emergence, survival and early growth of one year old Quercus castaneifolia seedlings were investigated in northern Iran. For this aim, nine plots (1000 m2) was randomly selected in opened (25%-35% cover), semi opened (45%-55% cover) and semi closed (65%-75% cover) canopies of a mixed oak-water elm stand. Two microplots (16 m2) were set up in each fenced macroplots. After planting 40 acorns in 5 cm depth of each microplots, emergence, survival, height and ground surface diameter of oak seedlings were measured. In the end of first growing season, the results showed that: though most seedling emergence occurs in tir but emergence process continues with descending trend till the end of first growing season. Seedling survival rate and height were respectively 71.1% and 15.8 cm and canopy density did not affect them. The highest emergence rate and collar root diameter occurred in open canopies because of higher light intensity in open canopies. It could be improved oak seed planting technique (sowing in 5 cm depth) success.

The Genu protected area encompasses Kuh -e- Genu, a single and isolated mountain rising above the Persian Gulf coastal plains, 30 km north west of Bandar Abbas. It covers an area of about 43000 hectares. This area presents a variety of habitats such as cliffs, rocky outcrops, alluvial plains and seasonal rivers. The main aim of this research is to identify plant species and introuduce the flora of Genu Protected Area. For this purpose, plant samples were collected during two growing seasons between 2003-2004 and identified using different flora references. The life forms were determined and the biological spectrum of the area was plotted. The position of the area related to phytogeographical classification was investigated based on geographical data and references.A total number of 516 species were identified, These include 6 Pteridophyta and 510 Spermatophyte (5 Gymnosperms, and 504 Angiosperms: 421 Dicotyledones and 84 monocotyledons).These species belong to 72 families and 317 genera. The rophytes with 223 species are the most frequent life forms in the area. The distribution of the 123 species is restricted to Irano-Turanian region. Of these, 44 species are endemic of Iran.

Rainfall is one of climatic variables that is very important in soil and water study. Therefore, information on the spatial variation of climatic variables is necessary in such studying. There are several methods to estimate rainfall along which interpolation methods are useful in this regards. In this study, 3 methods were used to estimate daily and monthly rainfall. These methods are: Thin Plate Smoothing Splines (TPSS), Weighted Moving Average (WMA) and Kriging..Cross Validation technique was used for comparison of the above mentioned methods. Variography analysis of daily rainfall showed good spatial correlation in these regions, however logarithmic transform of data showed better spatial correlation. Also, good spatial correlation was observed for July, August, September, October and November. Survey in above methods show that the TPSS method with power of 2 and WMA are the most precise method in estimating daily rainfall (MAE=0.6-1.2mm). The TPSS method with power of2 was recognized as the most precise method in estimating monthly rainfall (MAE values for monthly rainfall was calculated between 7 and 45 mm).

There are many ways to transfer data gauged watersheds to un-gauged which all is based on geographical vicinity whereas it is not the only necessity for the same. In the present study, 20 stations having a reliable and a lengthy data were selected and their data were analyzed to find out discharge values with 2, 5, 10, 25, 50 and 100 years return period.  In continuation 5 physiographical and 3 climatological parameters were extracted among which area and mean height were found to be more important parameters using factor analysis. The selected watersheds were then classified into 5 groups. The instantaneous discharge values were then estimated for each station situated in the same group and finally the error of estimations were calculated. The results of the study revealed that the efficiency of applied Andrew curve can not be finalized because of different values of error respectively equal to 174, 18, 156, 181 and 50 percent for the homogenous area 1 to 5.

To distinguish how light intensity (100%, 75% and 50% of whole sunlight coming) and root pruning (15, 30 and 45 cm of whole root length) affect Oak (Q. castaneifolia) seedling survival and vitality, a study in Caspian forest in factorial trial with 3 repetitions was Carried out. After two years; results showed light intensity ein fluences survival and vitality. soch that maximum amount happened of 75% Light intensity for survival. On the other hand; root pruning had not significant effect on survival as well as vitality. Meanwhile there was no any interaction between light density and root pruning on survival. Overall, best treatment regarding Oak seedling consist in a level of 75% of whole light with root pruned near to 45cm.

To recognize the phenologic stages of 7 native halophyte range plants species at Golestan province, lncheh-Broon station were selected as study area. This station is a representative of saline and alkaline regions. with respect to soil salinity and high salt concentration, raising the saline underground water in this area, most of the salt tolerance species grow in such environment and complete their life cycle. phenology of important halophyte species including: Puccinellia distans, Aeluropus littoralis, Aeluropus lagopoides, Frankenia hirsuta, Salsola turcomanica, Halocnemum strobilaceum & Halostachys caspica were studied since 1996-2000 during 4 years. Their phonologic stages including the initial growth, vegetative growth, flowering, seed rippening and dropping throphout the year. Results show that at the end of Winter, there were begun initial growth of most species. The flowering stages of perennial grasses occurred late of May- June and their seed rippening occurred in Jun-July whereas for the perennial species from chenopodiaceae family, the flowering stage occured at the end of August to September and seed rippening stage occurred in November and December.

Research on utilization of wastewood in our country is urgently required due to low per capita forest area. Pulp mills generally produce a large volume of wastewood. In this investigation, wastewood from under screen preparation line of the Iran Wood and Paper Industries (CHOOKA) was used. The investigation was conducted using environmentally friendly processes, both in cooking and in bleaching. Hence, instead of prehydrolyzed Kraft pulping, prehydrolyzed Soda/AQ process was used. After several preliminary cooks, three final cooking conditions were chosen, labeled as Al (Active Alkality: AA 26%, L/W 9), A2 (AA 28%, L/W 10) and A3 (AA 26%, L/W 10). The fixed variables were prehydrolysis and cooking temperature and times (170 QC, 90 and 150 min. respectively), L/W for prehyprolysis 7.5 and Anthroquinone (AQ) concentration 0.1%. Prepared pulps were deliberated and washed with warm water. These treatments were replicated at least three times and their effects on total yield, screened yield and Kappa No. were statistically analyzed. As a result, A3 was chosen as the optimum treatment. To separate uncooked barkchips, pulps screened with 16 mesh screen, were screened again with 50 mesh screen. In order to the process to be more environmentally friendly, bleaching was performed in 2 sequences with delignification agent, Oxone (X), followed by alkali extraction (E) and finally by an H2O2 sequence (P). The Oxone concentration was 4% and that of H2O2 was 6.5% (based on pulp O.D. weight). Oxone and H2O2 sequence temperature was 70°C; and for extracting, it was 60°C. This is the first time that an Oxone sequence has been used in Iran. The resulting XEXEP-bleached pulp contained 74.6% alphacellulose and 0.64% ash. This alphacellulose can be mixed with high purity alphacellulose to achieve both price reduction and quality improvement.

Investigation on restoration of non-regenerated canopy gaps of a beech (Fagus orientalis Lipsky) stand in Sangdeh forests (north of Iran) was carried out by planting beech nursery seedlings and beech forest (wilding) seedlings in three gaps of 50, 200, 600 m2 and one gap in open. The results reveal that at the end of the growing season, survival rate of each seedling treatment at one-year and two-year periods decrease as gap size increases. In 600 m2 gap and even in open place it does never decline from 54% at the end of the 2nd growing season. One-year height growth of both treatments, as well as two-year height growth of wildings, is smallest in open, and two-year height growth of nursery seedlings is greatest in 600 m2 gap. Generally, from this research it is deduced that in the investigated site, restoration of non-regenerated canopy gaps of the beech stand is practicable with plantation of beech wilding seedlings, Just as beech nursery seedlings, in gaps smaller and probably bigger than 600 m2.