Year:2008 | Volume:20 | Issue:4 (77 IN NATURAL RESOURCES)|Papers Count:33

Gracilariopsis longissima (Papenfuss) Steentoft, Farnham & Irvine is a member of Gracilariaceae (Rhodophyta) that is one of the important commercial agarophyte algae in the world with high quality and quantity of agar content. The study was carried out from June 2003 to June 2005 in the Persian Gulf (coast of Hormozgan province). Morphological and anatomical features and life cycle of the species were studied during this investigation. Morphological and anatomical study of the species and ecological factors of the distribution areas of the species are presented in this report.

A yellowish species of desert truffles grows in deserts of Tarom (Zanjan provinces). This species forms 5-10 cm below the soil surface and is yellowish inside. The truffles that had been collected from this area were investigated in laboratories. Cytological evaluations showed that each ascus contains 8 ascospores. According to morphologic and cytological characteristics, this species was identified Terfezia boudieri Chatin. This species is not ectomycorrhizal with trees. Because the vegetation in the area consists of moss, lichen and perennial sedges. The field and anatomical studies showed that Kobresia bellardii (Cyperaceae) have ectomycorrhizal associations with Terfezia boudieri in studied areas.

Frequency of natural regenerated seedlings of trees and shrub species in relation to physiographic and soil factors were assessed in Arghavan reservoir in north of Ilam. For this study، we used 57 plots (8´8 m2) and recorded seedlings and stump sprouts of woody species, soil and physiographic factors. Results showed that regeneration with seed origin of Quercus brantii has higher density in northern aspects and increases with elevation from sea level and soil fertility، while stump sprouts of this species was higher in southern aspects and decreases with increasing overstory. Acer monspessulanum seedlings had negative correlation with salinity and soil compaction. Ceracus microcarpa seedlings were abundant in northern aspects and prefer fertile soils. This study also showed that Crataegus orientalis and Cercis siliquestrum have not correlation with soil and physiographic factors.

Investigation of the methods of volume estimation and determination of appropriate method in Guilan forests in order to investigation a appropriate method for estimation of volume, 60 trees were randomly selected in 3 parcels of NAV Asalem district. The industrial, cordwood and stump volumes were calculated by Smalian’s, Huber and sylander formulas respectively and real volume was calculated from the sum of them. Volumes of the sample trees were been obtained from the simple formula, Pressler’s formula, using the form factor, the local volume tables (Chuca) and form class tables too. The normality test showed that data were not normal, so data get normal using Ln calculation on data. t-test paired is done on real volume with other five volumes and results showed that difference between the real volume with both simple formula and local table volumes were not significant, but it had significant difference with the three other volumes (Pressler, form factor and form class tables). Total results showed that volume obtained by local volume table’s estimates volume with more correction than other methods.

We arranged an investigation on new grown branches of 10 one-year seedling of Eucalyptus gunnii clone 634 to detect tension wood formation. Thin sections up to 5 microns were prepared by hystoresin method with a rotary microtome in serial form from apex towards base and were stained through various staining methods to detect tension wood. The results showed that tension wood formation in the form of gelatinous fibers, took place too early and it is visible at a distance of about 2 centimeters from apex after 20 days of tissue formation.

In order to study the structure of natural beech stands in the north of Iran (Neka-ZaLemrud region) we have defined two sections including two Land samples each 4 hectars in pure and mixed beech forests. Each plot was divided into 16 sub plots of 0.25 hectars. In each plots the common and horizontal structures, stem numbers, basal area and volume (per hectars) and was investigated by 100% inventory process, disteributions of stem number per diameter class during the investigation of stand structures and in order to preventiom of time and cost of study, we have followed those studies in order to find the minimum area. In addition to 0.25- hectare sections we have continued our studies in 0.5, 1.2 and 4 hectars scales. Results have shown that, with the increasing of the surfaces from 0.25 to 4 hectare, the uneven aged graphs were visible much better. Finally we conclouded that in pure beech forests in 1- hectare surface and in mixed ones in 0.5 hectare, we can reach to the given stand structure.

In order to assess the effect of mistletoe (Viscum album L.) on leaf area and weight and also some nutrients in host trees, the iron wood and hornbeam species selected as mistletoe’s prevalent host in the parts of the north forests of Iran. Five infected to mistletoe trees, from each species and a healthy tree near each, with similar condition of DBH, height and almost the same outward features was selected. Leaves samples from healthy and infected branches of infected trees and either perfectly healthy trees prepared to compare the amount of the elements. Moreover from branches with the same condition of diameter, length, infection intensity and sun light direction sampled in order to compare the leaf area and weight of infected and healthy branches. Results showed the increasing in amount of zinc and manganese nutrient in infected branches as compared with the healthy ones in all two species. Whereas the amount of magnesium and sodium have no significant differences in any of the two host species. Also, leaf area and weight of infected branches in compare with healthy branches of infected trees and healthy ones branches was decreased. The results of this study states that V. album species will decrease the host tree’s leaf area and weight and either disturb the nutrients equivalent of the host.

The target of this investigation was influence of particle geometry on physical and mechanical properties of particleboard. 54 experimental boards were produced using two type of particle (fine and coarse), mat moisture content gradient at 0, 3 and 6% and press time at 3,4 and 5 minutes. The physical and mechanical properties of boards tested and the results of these measurements analysed. The results indicated that particle geometry had significantly effect on modulus of rupture (MOR) of boards, and with increasing the aspect ratio of particles, MOR increased. The results showed that mat moisture content gradient and particle geometry significantly influenced modulus of elasticity (MOE). The highest MOE was achieved at highest mat moisture content gradient and the largest particles. Also, the results indicated that mat moisture content gradient and particle geometry had significantly effect on internal bond (IB). However increasing the mat moisture content gradient and particle geometry reduced IB, and the lowest IB observed at boards produced under 6% mat moisture content gradient and coarse particles condition. Even though, the results showed that particle geometry variable did not significantly effect on thickness swelling after 2 (TS.2) and 24 (TS.24) hours socking in water of boards. However mat moisture content gradient and press time significantly influenced these properties and increasing press time reduced T.S and increasing mat moisture content gradient, increased T.S.

For determination of distribution pattern in Smirnovia iranica in its natural habitat, soil chemical and physical factors in S.iranica habitat and control region were surveyed. This survey was done for reasons spot, disconnected distribution. Four site were chosen in Band rig, kaha. In all of regions sampling from plant and soil (3 profiles) was done.Density, canopy caver percentage, production, amount of damaged seed in the first and the end of seeding duration was done. Analysis of information was done by variance Analysis and T-Text software. According to results, plant communities were shown complety spot and disconnected comprison between Smirnovia iranica habitat and control region showed that all of facfors exept of N, K have not significant difference. Results of present research show that method of propagation in mentioned species can affect distribution.Soil factor has not any only effect on kind of distribution. But soil texture is only key factor for distribution.

The aim of this work was determination of the relation between Sorbus torminalis L. seed physiology and site conditions. Three sites of the species, called Pasand (located at 900 to 1050 meter a.s.l), Sangdeh (located at 1600 to m1800 a.s.l) and Ashak (located at 2100 to 2300 a.s.l) were specified on central Mazandaran forests. Ten healthy mother plants with enough seed were recognized at each location and their seeds were collected. Some of seed physiology characteristics including; 1000 seeds weight, Maximum and Minimum and mean of stratification time and germination precent were recorded. The results indicated that the mean of 1000 seeds weight was 21.86 grams. Minimum and maximum of the seed weight were observed in Ashak and Pasand sites respectively, without any significant difference between sites. The seeds of Sorbus torminalis in Iran need 3 to 5.5 mounths stratification to germinate. There were significant difference between sites about stratification time (p<0.01). Maximum of stratification time related to Ashak and minimum stratification time belong to Pasand site. Therefore sites with higher altitude require more stratification time. Difference between sites about germination percent was not significant.

In order to study on compatibility of Cupressus arizonica Greene, in 1995, 1521 Cupressus arizonica seedlings were planted in distance of 2´2.5 meter in Chamestan Research Station situated in a low land of Caspian Sea (north of Iran). The Results after 10 years showed that survival rate was very high about 92 percent. Mean diameter growth was 1 cm and Mean height growth is 79 cm. The standing volume 56 silve/ ha and the slenderness was 80 percent. The most fructification starts in fifth year. Generally, the results reveal that Cupressus arizonica has been adapted with region in the study period.

Gully erosion is a type of water erosion that tends to land degradation and instability of natural and agricultural lands. Whereas, gully morphology is a function of gully initiation process, so morphological investigations of gully is very important. This research tries to introduce the most important morphological characteristics of gullies in order to morpho-climatic classification of gullied regions in Chaharmahal and Bakhtiary province. To this case, two gullied regions covering an area about 500 ha were selected for each climate zone and three representative gullies were chosen in each region. The morphological characteristics were measured in each studied area. Gullied regions were classified using cluster analysis based on similarity of quantitative characteristics. The most important variables were determined by variance analysis and comparison on mean value of groups. The results indicate that gullied regions in Chaharmahal and Bakhtiary province with 245.2 km2 area can be divided to three groups basing on morpho-climatic characteristics. Maximum similarity level in groups was 94.12 percent. A comparison of variance analysis and mean value of variables in groups shows that, annual rainfall , elevation above sea level and gully length were significant in 1% probability level. In addition gullied region area and top width of gully were significant in 5% probability level. The other variables were no significant in separating of groups. Generally, we can emphasize that among all of the morphological characteristics, only gully length and top width of gully have the main role in morpho-climatic classification.

According to importance of aleppo oak (Quercus infectoria Oliv.) that is a fundamental species in Kurdestan forests, a study was conducted to determine the variation ranges of qualitative and quantitative observable attributes in acorn, each a nut and its cupule. In this study collected 390 acorn specimens from 26 forest societys(16 society in Baneh and 10 society in Marivan areas), then 11 quantitative and 6 qualitative attributes were measured and recorded. The obtained data were analyzed in a Nested model and Completely Randomized Design (CRD) using mstatc, minitab and genstat. consideration of 11 quantitative attributes resuletes showed that in the 4 nut attributes, style and nut length were the most and less variable attributes with ranges of 0/5-3 mm and 2/6-6 cm and CV =%34 and %13 respectively. Also, in the cupule quantitative attributes category(7 attributes), pedicel length and spiral number were the most and less variable attributes with ranges of 0/1-3/4 cm and 5-10 Spiral number and cV=%61 and %12 respectively. Furthermore, qualitative attributes results of Acorn (6 attributes) showed that nut form was the most variable one and %49/5 of nuts were cylindrical. A rate of %63/8 of the nuts had a smooth hilum. cupules had the less variable qualitative attributes in comparison with the nut attributes category. There were two state for each attribute, so that %89 of the cupules were cylindrical and the remaining had a roundish shape, %50/5 had a roundish shaped base and %49/5 had cuneate base, %80/8 of the cupules an undistinguishable scales on the surface and %63/1 of the scale apex were observed as undistinguishable.

Submerged vanes are hydraulic structures for sediment control at intake entrance. In this paper, hydraulic performance of these structures within high Froude Numbers was studied experimentally. A total of 24 experiments were carried out in a flume with 17m length, 40 cm width and 900 diversion angle with and without using a set of submerged vanes. Effects of angle variations of submerged vanes and discharge on intake ratio and water surface profiles near intake in main channel were investigated. The results showed that application of submerged vanes, regardless of their angles, cause the increase of water surface elevations near upstream vanes when flow parameter was 169 (30 lps, sub-critical flow) in main channel. Also, due to their relative high angle, an increase in water surface elevation was observed near upstream of 25o angle vanes when flow rate was 339 (60 lps, super-critical flow) in main channel. The experimental results indicated that in supercritical flow a sudden increase in flow depth occurred downstream close to intake when the submerged vanes were not used. Compared to the condition with no vanes, the results showed that the application of 25o angle submerged vanes causes an increase in intake ratio. However, a reduction in intake ratio was observed in the case of 150 angle vanes and no change was observed in intake ratio when the angle was 20o.

This study aims to assign natural regeneration of woody species diversity in four sites of 15 years alder plantation in Mazandaran low forests. In each site three plots 20´20 m are selected and one plot also implemented as the witness in natural forests around. The number of woody plants was counted in each plot, and diameter and height of generated species were measured up to 1.3 meters height. Species diversity was examined by using Shannon wiener function index as well as evenness and richness by using Simpson and Menhinic indexes. Results of this study illustrated that about 8 tree and shrub species were observed in planted sites naturally. And there is no significant difference about biodiversity indexes (diversity, evenness and richness) among planted areas and natural forest.

Continuous men’s needs to soil resources and increase of the common knowledge of soil degradation and erosion have aggravated need for confident evaluation and assessment of soil degradation rate and potential for food production. Revised Universal Soil Loss Equation is a model to predict longtime annual soil loss, related to rainfall-runoff, soil erodibility, slope length, steepness and support practice. The product of slope length L and steepness S is called topographic factor LS, implying the topographic effect on soil loss. The topographic factor is the most sensitive one in the prediction of soil loss. This study was conducted to predict spatial variability of LS factor using digital elevation model, in hill slopes of Talesholia district in Golestan Province, approximately covered 650 ha. Digital elevation data were prepared with 20m spacing. By using nearest neighbor resampling, new DEMs with 50, 100, 200 and 400 m resolution were derived from the original DEM. The LS factor was calculated according to a physically based topological factor LS equation for each DEM. Appropriate semi variogram models were fitted to semi variances and the best parameters were derived. Finally, the best DEM was chosen based on geostatistical parameters, total variances and mean semi variances at a lag of one cell. The results showed that with increasing the cell spacing (resolution), sill and nugget effect decreased and range increased from 92 to 171m. Spatial dependency increased with increasing cell spacing up to 50 m, but decreased extremely in the longer cell spacing. Total variances and mean semi variances also increased with increasing cell spacing to 50m. According to best spatial dependency and high variances and diversity of 50 m cell spacing, this DEM was proposed to predict LS factor by physical based model. Overall results of this study confirmed that geostatistical analysis accompanying with the statistical approaches could be applied to select suitable cell spacing in DEM to predict topographical factor in RUSLE model.

Spiral gall aphid is considered as an important pest of black poplar, P. nigra in Iran. Activity of the pest deforms leaves petiole to spiral shape gall. Consequently, early defoliation of infested trees occurs in mid summer. In 2000- 2001, ten Populus nigra clones already planted in randomized complete block design (5 and 6 years olds), were subjected to sampling procedures. In each experimental plot from 25 existing poplar trees, nine which placed in the middle of plots were studied. In mid summer, four branches of every poplar tree (120 centimetres) were cut and number of aphid galls was recorded. The branches were selected from four geographical directions of trees. All branches were selected from the same height of poplar trees. Analysis of variance of obtained data revealed a significant difference (a=5%) between tested clones. While, no significant difference was observed among the geographical directions of trees. The results also showed that clones Populus nigra 56/52 and Populus nigra 62/154 had the maximum and minimum pest densities, respectively. Furthermore, natural enemies of this pest in Zanjan climate are parasitoid wasps Aphelinus flaviventris and bug predator Anthocoris minki.

In order to study the effect of sowing dates on yield, yield components and quality of isabgol as medicinal plant in 2004-2005, an experiment conducted in research farm of agricultural faculty located near Sistan dam, 25 Km far from Zabol city, by using a randomized complete block design with three replications, and six sowing dates, including: 7, 17 and 27, Feb., 9, 19 and 29 March. Results showed that length of major and minor spike, leaf number, and spike number per plant, thousand seed weight and biological yield were significantly affected by sowing dates, but turgidity index, mucilage percent and plant height showing no significant difference. Study showed that the maximum plant height, major and minor spike length in 19 March, Thousand seed weight in 17 Feb. leaf number per plant, spike number and biological yield per plant in 9 March, were obtained. Results showed the maximum seed yield was in 17 Feb. and delay in sowing date from 9 March, caused yield reduction.

In this study the relationships between production as a dependent variable and canopy cover and volume as a independent variables for Atriplex veruciferum and Salsola dendroides were investigated and the best variable or variables for estimating the production of these species were selected. By using line transect sampling method; variables such as height, smallest and largest diameter and production were measured by using cut and weighting method. Multiples and stepwise regression analysis were applied to find the best variable or variables to estimate the production. The results showed that in both species canopy cover was the best variable to estimate production.

In order to determine the relation between Maple seed germination parameters and seed collection site condition, seeds of ten mother tree from 4 collection sites named Ladjim, Lemzer, Sangdeh and Ashak (400 to 2100 meters above sea level) were collected. Seeds of each tree were stratified in cold and wet sand in 4 replications. The results showed that maple seeds require 4, 18 weeks to begin the germination. Correlation between 1000 seeds weight with site altitude was not significant but was significant with tree diameter in brest height. Older trees produce bigger seeds. Effects of elevation on stratification time, germination time and final germination percent was significant (p<0.01). With increasing the site elevation the stratification time and increased the germination time and final germination were decreased.

Plantation with broad leave species mixed with native tree species of Caspian forests is one of the most important strategies of Iranian forest plantation plans. On this target, the plan of this research was established in 1995. The treatments including pure oak and four mixing rate mixed with zelkova that performed in Chamestan forest and rangeland research station. The plots dimension was 25m´25m and planting distance was 1m´1m. Two outer lines of plantation were omitted in inventory for decrease of buffer zone. All of other trees were measured and recorded. The measured parameters incluing: diameter at breast height, total height, pruning height, crown equality, verticality, multi trunck, curvity in main trunk, transversal branches. For data analysis, One Way ANOVA and Tukey HSD tests were performed for comparision of mixing rates. The results show that mixed plantation has better situation than pure oak plantation on the bases of growth condition improvement and fertility. The highest survival rate of oak was (85.53%) belong to treatment of 60% oak– 40% zelkova. Among all mixed treatment of oak and zelkova, the treatment of 70% oak– 30% zelkova showed best results of total height (9.27 m), pruning height (5.62 m), dominant diameter (10.9 cm), dominant height (12.67 m) and quality parameters such as crown equality, cylindric trunk, low amount of branches and other parameters including survival of zelkova, mean of dbh, mean of total height, meam of basal area, mean of dominant diameter, dominant height of zelkova, mean of dominant height, mean of height increment and growth.

Increasing population, urban expanding, environmental pollution, human activities such as developing vegetation and desert control, climate change, inversion and smog are factors that affect on human environment quality. Land surface temperature (LST) is becoming increasingly important. This study had been done on Yazd, Zarch and Ashkezar cities with area of 56273 ha. using RS and GIS and landsat 7 image acquired in 10th July 2002 at 10 o’clock. As we know weather station located in special points, therefore LST were calculated with several methods (1. proposed model for Seoul city. 2. Landsat project science office model. 3. proposed experimental model). Retrieved LST and weather station temperature were compared by paired T test. There were no significant difference between method 2 and 3 and weather station temperature, then these methods are suitable for this area. Average weighted temperature for sandy land, Epandaj plain, clay plain, planted saxtual land; urban, asphalted land and vegetation covered land were 30.9, 30.5, 30.0, 29.8, 28.9, 28.7 and 27.3 degree centigrade respectively. Barren area especially sandy land had highest and agricultural land had lowest LST, because of soil moisture and rate of vegetation cover. There were very high correlation between vegetation index (NDVI) and LST (r=0.99). Air pollution and desert condition are the main reason for relatively low LST and high variation in urban area. Not only the role of vegetation in LST is important but also, their distribution is important. The managers of urban environment must consider above points and for expanding cities must attention to LST of the countryside of cities.

Euphorbia belongs to Euphorbiaceae family and Euphorbiales order with annual and perennial plants which have cyathium inflorsence and laticifer. In this research 11 species anatomy structure of Euphorbiaceae were studied. The cross and longitudinal sections were prepared and cut (12 micron), Finally stained double staining. These species were divided to annual and perennial. In annual group, they were: E. cheirolepis, E. granulata, E. szovitsii, E. helioscopia. E. petiolata. E. densa, and in perennial group they were E. marshalliana, E. microsciadia. E. buhsei, E. aucheri, E. bungei. In annual group, It was considered wide medulary ray, laticifer in margin of cortex, and cluster arranging for vessels. In perennial group, It was considered gelatinous fiber, ring porous, diffuse porous, apotracheal boundny, solitary, cluster, and radial chain pore arranging vessel. Meanwhile leaves were isolateral and isolateral- dorsiventral. results showed any correspondence Species among the internal Structure of arrangment Vessel, isolateral, dorsiventral.

One of the problems encountered in developing in micropropagation of Eucalyptus is in vitro exudation of phenols.The release of phenolic compounds in Eucalyptus spp. is a common problem and generally caused death of explants. Therefore, neutralization or elimination of phenols release in the media is an essential measure in facilitating the establishment for further proliferation of shoots. Several factors contribute to the acceleration of this problem. In this research influence of three factors consisted: The use of disinfectants, including NaOCl and Ca (OCl)2, time of the year when explants were taken and age and woody character of explants studied and various treatments for neutralization or elimination of phenols released in the media by explants were examined. The experiment consisted of 5 replicates per treatment and each contained 4 explants in a completely randomized design. Analysis of variance (ANOVA) and Duncan’s multiple range tests were conducted using the SAS programme. The results showed that disinfectants, seasonal growth and age of explants accelerate the release of phenolic materials. Also the results indicated that the best treatment with respect to explant establishment and reduction of phenolic production was obtained when cultures were kept in the dark and frequently subcultured- three times at four day intervals.

This is illustrated by frequent occurrences of severe droughts and floods. The challenge is to determine whether these hydrological hazards and disasters are the result of climatologic variability or of man-induced changes. This study provides an alternative approach to assess the actual changes in hydrologic response of a watershed in an arid tropical region to land use transformations made in the past 25 years. The approach combines remotely sensed image data from satellites with in-situ hydrological observations from the Minab catchment’s (ca. 1.106 ha). Results of long-term analysis of historical time series on rainfall, land use and stream flow are integrated at the landscape level, to identify appropriate options for land and water management. In 1976, about 45 percent of the watershed area was covered by rangeland and natural forest. Due to continued overgrazing, rangeland cover decreased to 8 percent in 2002. Three main land use classes have replaced these fertile rangelands. These are: poor natural cover, agricultural area and residential area. The destruction of natural vegetation resulted in a decrease of the annual total water yield by 3.4 mm, with a decrease in the base flow during the low-flow period (May-November) and an increase in the storm runoff during the high-flow period (December to April). It can be concluded that climatic variability and land use change are the most important factors affecting the (changes in the) hydrologic regime of the Minab catchment’s. For a flood return period of more than 10 years, (high) rainfall intensity as a climatic factor is considered dominant. For a return period of less than 10 years in combination with a low flow period, land use change is the dominant factor determining the flow regime. An active management strategy aimed at the conservation and regeneration of the natural vegetation is recommended, in order to improve the distribution of water throughout the entire Minab catchment’s, during both dry and wet periods.