RESEARCH JOURNAL OF FOREST SCIENCE AND ENGINEERING
Year:2011 | Volume:1 | Issue:3|Papers Count:7

Mass movements have caused important economic impacts in most of the provinces of Iran affecting roads, railroads, communication systems, irrigation and water channels, residential areas, forests and rangelands. Preventing the increase of costs and risks relating to land slide, it is necessary to identify and classify it and find the factors forming it in forests. There are several methods for landslide classification that are based on soil characteristics and movement on slopes and suggest techniques preventing its spreading. The landslide studied in this research is 500 meters in length and 70 meters in width located in Mazandaran Wood and Paper Co. forest (Tajan watershed, Mazandaran, Iran). First, some height measurements were performed by Teodolit Digital camera in 12 points (between two permanent points on both sides of the landslide and along the road) in both dry and wet seasons. Also, soil samples were obtained from the landslide at 20-40 cm depths. The landslide and its movement were classified due to soil components and its texture and natural moisture. The results showed that movement areas had soil with Low plasticity Clay (CL) and the control area had Medium plasticity Loam (ML) with 49 and 40 percent humidity, respectively. As the liquid limit is related to clay percent in soil, its high content showed that the amount of clay was high in this region. It was concluded that the reason of the landslide was soil satiation. Meanwhile, regarding to the specific soil condition in this area, it is susceptible to landslide and because of operations such as oil transmission pipe disturbed the drainage system, humidity was accumulated in soil and has lack of proper drainage.

Bark water storage capacity (BWSC) is an essential component in understanding the processes of throughfall and stemflow yield in forest ecosystems. The purpose of this study was to quantify BWSC of bole of forty-year old Pinus eldarica trees with an average dbh of 25 cm planted in the Chitgar Forest Park near Tehran city, Iran. To determine bark water storage capacity, twenty two bark samples were air dried in the laboratory for one month. Each bark sample was then completely submerged in water-filled laboratory-based cylinders for at least 72 hours. The percentage looses of water was determined in the laboratory after 1, 2, 3, and 24 hours. The average of BWSC of Pinus eldarica was estimated to be 0.337 g cm-3. 68%, 17%, and 15% of average BWSC values were stored in the first 24 hours, the second 24 hours, and the third 24 hours, respectively. The average loss of moisture in 24 hours after air drying of the samples was 0.16 g cm-3. It was found that BWSC of the tree bole of Pinus eldarica with an average dbh of 25 cm was 15.3 lit m-2. The significant quantity of water stored in the bark of Pinus eldarica emphasizes the influence of this species on the geo-ecology and hydrology of the coniferous forest biome.

The opening of gap in the forest canopy cover causes light to shine more forcefully to the forest floor, and it makes changes in organic layers and forest soil. In this research, parcel 18 of the forestry plan in Jamand district was selected, which was fully callipered and all of the natural gaps in it were investigated and their effects on forest floor and upper most mineral soil layer properties were studied. In the center of each gap, samples of organic layers (layers L, F, H) were taken from 0.25m2 area and soil samples from 0-15cm depth. In this research gap sizes were studied in 4 classes: 1st level (50-200 m2), 2nd level (200-400 m2), 3rd level (400-600 m2) & 4th level (600-800 m2) and they were analyzed. According to the results achieved, the amount of the percentage of moisture in organic layers (layers L & F) was influenced by the gap size and it had a significant difference at 5% level. Increasing the gap size, the percentage of moisture in these two surface layers was decreased. Organic Carbon (OC) and amount of C:N in the H layer had a significant difference at 5% level, as the highest amount of them was in the first class and the lowest amount was in the second class. Also, the total Nitrogen (N) of soil showed a significant difference at 5% level, as the highest amount of it was observed in the fourth class. Generally in this research, the second class could provide the best condition for decomposing and increasing the rate of nutrient return.

The importance of biological diversity and its management which especially is based on the protection and stable exploitation from ecological resources is one of the main purposes in natural resources management. Biological diversity can be investigated from different aspects that some of them are variety of physical and chemical characteristics of bed rock, earth forms, geological processes, domestic and ecological materials which have vital and critical role in distribution and growth of plants. To perform this research, the third district of Kheiyrud forest which is a suitable index of Hyrcanian forests had been considered and its plant community was sampled in May, August and November 2010 in three stages. The samples were taken in all geographical directions (northern, southern, eastern, western, north eastern, north western, south eastern, south western and flat parts). Dimensions of quadrate were 20*20 meter (400 square meters) and number of them was 60 sampling units. Based on performed calculations, indices and samples of biological diversity showed that southern directions have the most amount of diversity and areas without geographical directions have the most amount of homogeneity.

Road construction has negative environmental impacts such as forest area reduction in microclimate, destruction of natural drainage, soil degradation and river water sedimentation and light regime changes, pH, moisture, etc. The purpose of this research was to investigate the chemical properties of soils beside the roads and its effects on the growth of Alder growth on the roads type I and II. Darbkla Forests were studied in this research. To understand the studied effects, the stands inside the area were also measured and compared. Diameter at breast height and height of Alder trees were measured at the edge of the road type I and II and inside the stands. The soil chemical characteristics (N, CaCo3, Ca, C, P, K, Mg, EC and pH) were measured. Data analysis was performed in SPSS. The Results indicated that despite the difference between the amounts of nutrients in the soil bordering the roads type I and II, no difference was observed between the growth parameters. Diameter at breast height was higher on the road side comparing inside the stand but only the organic carbon in the soil of roadside was higher than the stand. Although there was no significant difference in the concentration of soil elements upstream and downstream of the road, but the height of trees above the road was significantly higher than the down parts. The results showed that there was no much difference between the environmental impacts of these two types of roads. Since because of the environmental issues, roads of type II are constructed in some areas the type I is needed, in general, it can be said that roads of type I can be constructed in necessary areas under environmental standards.

The purpose of this research was to find out the ecological development of Avicennia marina in the hyper saline condition. So artificial inlets were digged in Bushehr beach in 2003 in Sabkha lands. Vegetative characteristics of seedlings such as height, diameter, and crown diameter were measured inside and outside of the inlets. Also some physico-chemical properties of soil such as salinity, soil acidity, soil texture, potassium, phosphorus, and nitrogen were measured there. The results showed that there was a significant difference between elector conductivity (EC), pH, K, and the percent of sand inside and outside of inlets but the differences were not significant for N and P. Halophyte plants such as Salicornia herbacea and Halocnemum strobilaceum as well as animals such as mudskippers were observed in the study area after 7 years. Silt deposition affected the seedling growth and caused a significant difference inside and outside of inlets.

Precise quantitative information of the young forest stands is necessary in their scientific and technical management and direction of the forest stands toward sustainability. In plantations, the working unit can be a single tree rather than the area, or the smaller areas of sampling can be used for measurement. N-tree sampling method is one of the distance techniques used for measuring the quantitative and qualitative characteristics in forest stands. In this study N-tree sampling methods (3, 4, 5, 6, 7, 8, 9 and 10) were assessed to measure number, basal area and volume per hectare in a 12-ha plantation in the north of Iran. At first the plantation was fully callipered. Then a 50×50 m grid was determined for N-tree sampling method application. The result of t-test showed that mean in basal area per hectare estimated by Prodan's estimator, in 5, 6 and 7 trees had significant difference with 100% inventory, but means estimation of these characteristics from other methods was acceptable. Estimating means in the number per hectare and volume in hectare by Prodan's estimator did not have any significant difference with 100% inventory in the all of N-tree sampling methods. At last, using E%2×T, the 4 tree distance sampling method was suitable for sampling in populos delteoides plantations.