فهرست مطالب صغری کی بندری

The mechanical behavior of vegetation roots significantly affects the mechanism of soil reinforcement and slope stability. The aim of the present study was to determine the mechanical properties of seedling roots of some tree species in the second district of Kheyrud forest. Ten samples of each species (beech (Fagus orientalis Lipsky.), hornbeam (Carpinus betulus L.) and, maple (Acer velutinum Boiss.)) completely extracted from soil and all roots were collected, then their mechanical properties were measured in the labratory. The results showed that in all species, the relation between root diameter and tensile force, was positive power law whereas the relation was negative power law for root diameter and tensile strength and also Young’s modulus. Results of ANCOVA showed that tensile force, tensile strength, and Young’s modulus were significantly different among species. Accordingly, the average tensile force and tensile strength for hornbeam species were 48 and 40% higher than beech and maple species, respectively and the average Young's modulus of beech species was 38% higher than hornbeam and maple species. The findings of this work show that the mechanical properties of the roots can be used as an indicator in selecting species for soil bioengineering purposes. Therefore, it is recommended that these properties be considered in soil reinforcement modeling.

Roads are not indispensable in forest management and without them there is no possibility of achieving different management goals and permanent access to different parts of the forest. Economic, protective and service objectives can only be achieved by building a suitable network of access roads to the forest. Since the forests of the north of the country are the only natural source for supplying the timber needed by the country's industries, the significance of these goals is significant. Therefore, the first step in the implementation of any forestry plan is to design and construct a road network with a density and appropriate coverage in the area in question. Without roads, access to most forestry products and services will not be possible, although it should be noted that the construction of a forest road has the greatest impact on forest exploitation operations, which causes the destruction of the forest environment. On the other hand, the forest road is especially important due to the heavy costs associated with design and construction as well as the negative effects on the environment and wildlife. For this reason, at all stages of project preparation and construction of forest roads, the network is being tried The road is designed and constructed to provide the least harm to the environment in addition to easy access to the entire forest level. One of the things that should be considered in designing a road is the discussion of tourist and recreation, which is a perfect road that can be used as a recreational amusement. Thus, in designing the road, it is necessary to maintain the ecological balance of the forest and to preserve biodiversity and maintain the biological bases of endangered species and to preserve the nature of the protective zones of the fishing hunting, other local recreation and economic needs, Social and Demonstration. The study method of this study was qualitative and with the review of library resources. A review of studies has shown that for designing of forest road network, all aspects have to be taken into account and all relevant factors such as physiography, soil science, geology, vegetation and socio-economic factors should be considered for conservation and Optimized productivity.

Vegetation in riparian areas, including trees with various hydrological and mechanical effects has an essential role in soil reinforcement. This is accomplished by increasing soil shear strength and inhibiting the higher layer of soil into the lower layers and reducing erosion by roots. The aim of this study was to evaluate the tensile strength changes of Salix purpurea L. trees in different trunk distances and soil depths. Therefore, five trees were randomly selected for root system sampling, which was done by using the soil core technique. Sampling was taken in three different depths, tree horizontal distances and in four directions of the trees. Finally, 97 successful tensile tests were performed on root samples. The relations between tensile force- diameter and tensile strength-diameter were analyzed and compered. The results showed the average of tensile strength of 57.91, 46.96 and 46.27 Mpa for depths 0-10, 10-20 and 20-30 cm, respectively. Furthermore, the average of tensile strength was 29.18, 76.81 and 28.78 Mpa for 0.5, 0.75 and 1 m distances, respectively. Root diameter and tensile force fallowed positive power and exponential trends. However, the association between root diameter and tensile strength followed a negative power trend. Results of Wald test showed no significant difference between tensile strength of three soil depths and three horizontal distances, though root diameter as a covariate parameter with a significant effect on tensile strength.

This study aims to determine zone effect of secondary forest roads on flora, life form and chorology of beech-hornbeam stand in Kheyroud forest of Nowshahr. 36 transects with the length of 100 m (number of 18 transects on each of up and down slope) from road edge in to the forest interior were selected, also number of eight plots with the size of 1×2 m at the distances of zero (road edge), five, 10, 15, 20, 30, 45 and 100 m were established. Edge effect of roads on the frequency of the plants was appeared up to five meter because after this interval, Fagaceae and Betulacese families were dominant and Rosaceae, Cyperiaceae, Aceraceae and Poaceae were as a light tolerant family so the presence of them decreased. Edge effect of roads were apparent up to five meter, because after this distance Chamaephytes did not exist and life form of the study site changed from Phanerophytes to Hemicryptophytes. Roads of the study site had an effect on chorology up to five meter. After this distance semi cosmopolitan and cosmopolitan decreased and percentage of Pluriregional and Europe-Siberian increased.