Year:2005 | Volume:17 | Issue:1 (66 IN NATURAL RESOURCES)|Papers Count:13

This study was done to show the effect of light intensity (100%, 75% and 50% of whole sunlight) and root pruning (15, 30 and 45 cm of whole root lenght) on oak (Q. castaneifolia) seedling growth. The study was done as split-plot design and factorial experiment woth 3 replicates in Caspian Forests, north of Iran. The results of 2nd year after plantation showed the significance of sunlight on height growth. Maximum height growth happened under 50% and 75% light intensities. On the other hand, root pruning did not have any effect on height growth but had no collar diameter growth where as the minimum was occured over the roots pruned of 30 and 45 cm. There was no any interaction between light density and root pruning on height growth as well as collar diameter growth. Overall, the rootpruning more than 30 from seedling collar and light level less than whole sunlight were the best treatment for obtaining the thicker and longer oak seedlings.

Rangelands in Maravetapeh with the loose soil not only are the major area for grazing animals in Golestan province but also they are as the winter rangelands for the animals that migrate to this area. thus the area is under over grazing. In order to recognize any changes in infiltration, runoff coefficient and bulk density of soil, which are very important in erodibility of soil erosion, an investigation was carried out in the form of completed randomized blocks in 3 replications. The experimental treatments were selected as: 1-Not grazing plots, 2 - Grazing equal to the half of productivity capacity, 3 -Grazing equal to of productivity capacity, 4 -Over grazing to the double of productivity capacity and 5- Over grazing to the triple of productivity capacity. Bulk density of soil surface 3 form treatment number 3 is highest and it is equal to 1. 27 gr/cm3. The lowest value of bulk density in soil surface is 1.09 and it is belong to the treatment number 1 and 2. Amount of runoff after each rainfall event has been measured. Infiltration rate and bulk density of soil surface were determined in the end of each year. Analysis of variation has been done and the results showed that the infiltration rate of 11. 67 cm/hr in the soil under over grazing to the triple of productivity capacity is the lowest value, while, this rate in the no grazed area as well as in the soil under grazing equal to the half of productivity capacity is highest value which is around 25.24 cm/hr. the amount of runoff in treatment number 1 and 2, is equal to 45. 6 m/hec/year and this figure is equaled to 130. 28m3/hec/year for treatment number 5 (triple grazing). Tus The over grazing in this kind of rangelands therefore causes compaction and increasing runoff coefficient.

Loess is one of the most important quaternary sediments units. About 3000 K.m2 of Golestan province is covered by loess deposits. Due to physical and chemical characteristics, these sediments are sensitive to erosion and sediment yield. The loess sediments of different regions show different erosional features: Gully and tunnel erosions are widespread in arid and semi-arid regions, but they are less abundant in temperate and semi-humid areas. Chemical, physical, topographical and climatic factors play important role in erodibility and sediment production of these deposits. In order to study these relationships, the maps of loess distribution and climate were prepared using satellite images (TM) and other available data with the help of Ilwis software in GIS (Geographic Information System). By combining two mentioned maps and other observations, five localities with seven replications were chosen for the investigations. 35 soil samples were taken for the analyses. Texture amount of organic matter, calcium carbonate, electrical conductivity and acidity of the soil samples were determined in the laboratory. For the measurement of sediment yield quantitatively, a small rainfall siniulater was used in the field and runoff and sediment were collected. The effect of independent variables including physical (percentage of clay, silt and sand), chemical (pH, Ec, the amount of calcium carbonate and organic matter), topographical (elevation) and climatic parameters (De-Martton aridity index) on sediment yield of loess deposits and soils was studied by stepwise regression analyses. The amount of organic matter and De-Martton aridity index show very high correlation with the amount of sediments. Accordingly, loess deposits were classified into ones having low, medium and high sediment yield. The loess deposits of humid and subhumid regions have low sediment yield and ones from arid and semi-arid regions have high sediment yield, others have medium sediment yield.

In order to investigation the effect of mechanical and chemical treatments on seed dormancy and its germination in Tilia platyphyllos, a completely randomized design was used with 14 treatments in 4 replications. Treatments included hot water 80°c for 10 minutes, warm water 60°C for 30 minutes, 30% Sulfuric acid for 10 minutes, 15% Sulfuric acid for 20 minutes, 1%H2O2 for 20 minutes, 1% H2O2 for 40 minutes, control treatment including stratification in decayed saw dust and river sand. Results showed that best germination rate belonged to hot 80°c water for 10minutes in the period of 45 days in decayed sawdust and the lowest rate of germination in treatment belonged to 30% Sulfuric acid for 10 minutes, 1%H2O2 for 20 and 40 minutes in the period of 90 days and control treatment including 180 days stratification in sawdust and sand.

In this research, anatomy and palynology of Muscari Mill. species in Iran were studied. Muscari is belong to Liliaceae family of Liliales order. This genus has 7 species of 3 subgenus: Leopoldia, Botryanthus and Pseudomuscari in Iran. For anatomy studying, It's prepared fongitudinal and cross sections of root, stem and leaf by microtome and painted by double - staining. In palynology studying equatorial and polar length were Studied by LM and researched surface of them by SEM. In anatomy, we can not regcognize difference between species and subgenuses but about pollen, there is differences between subgenus.

In this investigation the effects of preservative materials and impregnation processes on mechanical properties of: Eucalyptus camaldulensis has been studied. Trees have been cut from Norabad Mamasani. For impregnation of wood the following methods have been used; (1) Bethell method, (2) Ruping method and (3) Double Ruping method Regarding the preservatives, creosote, FCAP and CCA type A, have been chosen and 2 W.B have shown good results (NaF 24%, crO3 35%, As3O5 24%, 2,6 (OH) C6H3 (NO2)2 17%) and (K2Cr2O7 23.8%, H2O 12.5 %, CrO3 28.7%, H3As04 17%, CuC03 18%). Regardless the kind of preservative, it has been found out that the mechanical properties have been highly decreased in the samples treated total. The reasons of reduced mechanical strength are as following: Double drying, the crack of wood, dry stress, acid hydrolysis of cellulose unit preservatives absorption, thermal treatment, volatility of preservatives.

Identification of poplar clones isnot easily possible using morphological attributes. This approach however, does not render a proper differentiation. In order to recognize the clones especially on early growth stages, molecular markers based on DNA polymorphism are suitable. In this study, 12 clones from 4 species of Populus belonging to different area of Iran, as well as 86 clones from 4 species belonging to populations of Netherlands, were investigated for scree genetic diversity and their differentiation. For using microsatellite markers, following DNA extraction from young and fresh leaves, Polymerase Chain Reaction (PCR) conditions were optimized and conducted with 7 primer pairs to amplify Simple Sequences Repeats (SSR). The PCR products were visualized using agarose gel electrophoresis and detected by staining with ethidium bromide. For demonstration of polymorphism among clones, PCR products were visualized using polyacrylamid gels electrophoresis and detected by silver staining. The data were analyzed by pop Gene software. Results showed that, the number of alleles at the SSR loci ranged from 9 to 13, with an average of 11.11 alleles per locus. The observed heterozygosity ranged from 0.13 to 0.98, with average of 0.71 per locus. Furthermore, hybrid poplar clones have shown most heterozygosity among the poplar species. As well as poplar species and their clones has identity according to systematic classification. In this regard hybrid clones has shown most similarity with P. nigra clones. Meanwhile, similarity and genetic distance between populations has shown by a dendrogram.

The region under study with the area of 16873 hectars is located in the south of Ghum. The highest altitude of it is 3070 m. above the sea level and the lowest is 1050m. The average rainfall, according to the neighbourhood synoptic station is ca. 252.8mm. Researches and investigations on the plant vegetation of the mentioned area have revealed the presence of 484 species belonging to 62 families and 274 genera. The largest plant family, in terms of number of species is asteraceae with 79 species and the largest genus, in terms of species is astragalus from papilionaceae family with 19 species. The diagram of plantbiotic spectrum indicated that the life forms of the plant species of the mentioned area include: Hemicryptophytes 41.96%, therophytes 29.65%, Chamaephytes 12.94%, geophytes 10.23%, helophytes 0.62% and phanerophytes 4.60%, representing the environment with a cold and temperate climate. 410 species(84.71%) of the area are exclusively Irano-Turanian region. Furthermore, according to the IUCN or the World Conservation Union, three cataegories of plant species so called vulnerable, Lower risk and data deficient are determined. There are, in total, 69 threatened plant species in this area.

In this research the effects of irregular Ware,s reflection from the reshaping rubblemound breakwaters were investigated. Reshaping breakwater is a kind of new breakwaters, which its initial profile is changed to a (S) shaped one after impacting of waves. Therefore, the relations related to reflection coefficients on conventional breakwaters cannot be used for this type of structure. Method of research was based on Experimental modeling. Experiments were done for multiple cross sections of reshaping breakwaters with three different slopes in the Soil Conservation and Watershed Management Research Institute (SCWMRI) wave Flume, during 2003 to 2004. The wave flume equipped with a modem DHI wave generation system, which contains paddle, power pack, hardware and software divisions. The hydraulic response that mentioned above, were investigated by changing the wave parameters such as significant wave height, mean and peak wave period and storm duration on the three structure's seaward slopes, equal to 1:1.25, 1:2.0, 1:2.5. JONSWAP wave spectrum was used in all experiments. The Armoure layer materials were included in three grading class (Dn85A/Dn15A=1.14,1.44,1.82) and a Range of structural notional permeability index Pe (1≤D50A/D50C≤20) In order to changing structural geometry, wave properties and comparison between two scales (A = 50,30) , 120 tests were done with 1000 to 6000 waves in this research. At the end, comparisons between the results of different scale factor were done. The experimental results were plotted as graphs showing the reflection coefficients versus the surf similarity parameter and deepwater wave steepness. because the Iribarren number does not accurately describe the combined effects of slope and wave steepness, an improved and new fit to data can be achieved using multiple linear regression and nonlinear regression which results in some new empirical equations which has been presented in this research.

This study was conducted from 2000-2002 to revnue and optimiz the method for resin extraction from Pistacia atlantica to minimize the minimum damage to these trees. This experiment was condutted as factorial randomized complete- block design. This research was based on Three groove factor in levels of (10, 20 and 30 groove).the langht groove in three levels was ( 2,4 and 6 cm) . the position of the grooves were (horizontal, vertical and diagonal) the effects of these factors were studied and observed on amount of quantitative, qualitative of freshness, color of left, annual growth of branches liner and wide growth factor of left. The best method to reduce minimum damage to these tree for extraction were according to 30-50 cm diameter (20 groove in 2 cm horizontal grooves). 50-70 cm diameter (20 grooves in 4 cm vertical position). 70-90 cm diameters 30 grooves in 4 cm horizontal in sequence. they were the best method to apply for resin extaraction product from Pistacia atlantica trees.

The Loblolly pine (Pinus taeda) is one of the exotic and main species which is planted in the Gilan province. In total 150 sample units were collected from the Pinus taeda stands in the Lakan area. The Hohenadl-Kernn's regression model with r = 0.9591 is used to produce one factor volume table of the Pinus taeda. The W. H. Meyer's model with r = 0.9826 is used to produce two factors volume table of the Pinus taeda in the north of Iran. These tables are evaluated using 12 trees in the study area. The accuracy of these models are 3.53 and 1.53 percent. Null hypothesis are carried out to test the equality of variance and mean of estimated (V1, V2) and real (Vr) volumes of the measured trees. The null hypothesis are not rejected at the level of α= 0.01. It means, the estimated and real volume of the measured trees are not significantly different in this study.

This study was carried out in order to compare the stablishment of 7 needle leaved and broad leaved species and their resistance to drought in semiarid site in Talar river basins (Grabsar region of Masandaran province), since 1369. Experimental design was completely randomized blocks with 3 replications and 7 treatments (pinus brutia, Cupressus arizonica, Cupressus sempervirens var. Horizontalis, Tetraclinis articulata, Robinia pseudacacia, Ailanthus altissima, Celtis australis). Survival, mean collar diameter, mean hight and qualitative parameters were measured and analized after 5 years. Analize of variance show that differences between treatments are significant so that Cup. Semp. Var. Horizontalis, Celtis australis and Cup. arizonica were successful, Pinus brutia was promissing spieces and the other species were not successful.

Ulmus glabra is one of the most important species of the industrial forests of northern forests of Iran. It is distributed from Gorgan (at the northeast) to Arasbaran (at the northwest). Due to development of Dutch elm disease in their habitats, countless numbers of this species have died and its presence in the forest ecosystems is in danger of being eliminated. There have been so many studies and efforts to save this valuable species all over the world. One of the efforts has been focusing on the evaluating both sound and diseased individuals in order to study natural balance ecosystem on sound physiological trees. nowadays one of the methods that are used to assess the ecosystem is to study the soil microorganism enzyme. Based on decreasing living conditions from top to bottom of the soil and also increasing living limits biological potential (constraints) towards the deep soil, the frequency of micro and macro organisms will decrease. Therefore the soil enzyme activities that are themselves related to these activities have a descending gradient from top to lower levels of soil. If the natural process for any reason will be abrupt may lead to an unbalanced ecosystem, which at the end will result to migrate to the living organisms to the lower levels. This will cause the change of the gradient shape and will follow a fluctuation. In this research, following the theorem and emphasis on phosphomonoesterase enzyme study, the soil of four forest habitats were studied which were located at Gorgan, Noshahr, Asalem and Arasbaran. Sampling was done on during Spring of 2004. The soil samples were analyzed and phosphomonoesterase activities were measured. The goal was to study the effects of natural balance on both sound and diseased elm individuals in normal and abnonnal ecosystems. The results were analyzed by GLM (General Linear Model) method and were compared by Tukey test. The results show that all of the sound elms are on the balance ecosystems (except one) and the diseased ones are on balanced. In addition the comparison of enzyme activity in each horizon in both groups shows that decrease of organisms activities in unbalanced elm ecosystem is quiet significant. In fact it can be stated that to save this valuable species it is not enough to only follow and find the resistant phenotypes and genotypes elms to Dutch elm disease. In other words, the interactions of different biological factors and balanced ecosystems have the main effects on saving sound elms, which may result to control the disease. This means that we have to induct a sound and powerful management for these forests.