1- University of Tehran
Abstract: (12 Views)
Introduction and purpose: Forests are considered the national capital of every country, and in Iran due to being located on the dry belt of the earth, double importance should be given to its management, protection, and development. In forest management based on sustainability, regeneration of forest and natural habitats is very important to achieve the goals of sustainable forest, therefore, forest managers and foresters after exploitation or disturbances resulting from natural disasters such as mass movements and landslides or fire, revitalization and restoration of the forest's tree-grass cover in a natural way and with minimal human intervention. Landslides are one of the most common and these disturbances are the most important. The occurrence of landslides can be affected by topography, geological structure, soil depth, and the integrity of roots. Researchers have found that it is possible to deal with landslides by increasing soil strength and developing plant roots and vegetation. And it is preventable. It has also been determined that the probability of landslides is higher in grasslands and pastures than in forests, and tree cover is essential in areas prone to landslides. Thick roots act like nails on the soil on the slope, and the arrangement of thin roots connects these roots to each other. For this reason, with suitable root tissue of all types of plants and surface vegetation, slopes can be stabilized and soil hydrological conditions can be improved. Therefore, this research aims to investigate the natural revitalization of vegetation in areas where shallow landslides have occurred.
Materials and methods: For this purpose, 2 shallow sliding areas, which are called sliding areas A and B in this research, are located in Section 4 of Series 4 of Mazandaran's Nika Wood Forest in Plot 25, which has beech, alder and alder tree species. , oak, shirdar, van and walnut, and had landslides of about 6 and 8 years with a size of 700 and 1200 square meters in the direction of the northwest slope at a height of 486 and 610 meters above the sea level, they were selected and at a distance of 10 A meter in the adjacent area, parallel to the same sliding areas, was considered as a control, and to check the type and number of plants, 24 sample pieces (including 12 sample pieces in two sliding areas A and B and 12 control sample pieces) with a square of one meter square and randomly selected. The plants in each sample plot were first identified and then their number was counted. Then, according to the harvested plants, the floristic list of plants to identify and categorize the species, family, chorotype and biological form of each plant was specified and entered in the floristic table. The number of established plants separated from the sliding and control areas and their belonging to wood-tree and herbaceous species and their abundance were determined with the help of Excel software and the comparisons were done with independent t-test through Spss software.
Findings: The total number of harvested plants was 351, which is equal to the floristic characteristics of the sampled plants. The results showed that they belong to 19 plant families, which include four tree families (maple, hemrose, parsnip, and alder) and 15 grass families (of which 5 species are abundant. It includes: Jagen, Ferfion, Raspberries, Banafsheh, Matamati). Of all the sampled plants, 22% were found in the two sliding areas and 78% were found in the control areas. The plants harvested in the landslide areas were 87 pieces, all of which were herbaceous plants and there were no woody species among them. The findings regarding the difference in the growth status of plant species between the sliding areas A and B with the control and adjacent area, according to the paired comparison, the number of species and the abundance of plants were strongly affected by the disturbance caused by the sliding movement. They had a decreasing trend compared to the control areas and the results were statistically significant at 95%.
Conclusion: The creation of disturbances such as shallow landslides causes a significant decrease in the number and diversity of plant species, so that in the landslide area, native plants have not been established and restored according to the model of the control area, and 10 herbaceous species Such as cyclamen, primrose, sedum, fern, zebrina, etc. were not observed after the slip. And considering the absence of tree species in the landslide area, despite the passage of 6 and 8 years since the landslide occurred, the negative impact of the disturbance caused by the landslide on woody species is quite clear, but in The grass of this establishment, although in a small way (compared to the control area), is being restored and restored naturally. It is noteworthy that fast-growing herbaceous species such as jagen, farfion, and raspberry were established earlier than other species in the two studied areas, and the manner of competition, seed distribution, germination, number of seeds, physiology, ecophysiology, and other characteristics of these species may have been effective in their success in occupying the landslide areas. It was also found that about half of the plants in the area (before the landslide) did not return to the area, especially woody plants, at least in the short term, according to the observations of the control areas.
Materials and methods: For this purpose, 2 shallow sliding areas, which are called sliding areas A and B in this research, are located in Section 4 of Series 4 of Mazandaran's Nika Wood Forest in Plot 25, which has beech, alder and alder tree species. , oak, shirdar, van and walnut, and had landslides of about 6 and 8 years with a size of 700 and 1200 square meters in the direction of the northwest slope at a height of 486 and 610 meters above the sea level, they were selected and at a distance of 10 A meter in the adjacent area, parallel to the same sliding areas, was considered as a control, and to check the type and number of plants, 24 sample pieces (including 12 sample pieces in two sliding areas A and B and 12 control sample pieces) with a square of one meter square and randomly selected. The plants in each sample plot were first identified and then their number was counted. Then, according to the harvested plants, the floristic list of plants to identify and categorize the species, family, chorotype and biological form of each plant was specified and entered in the floristic table. The number of established plants separated from the sliding and control areas and their belonging to wood-tree and herbaceous species and their abundance were determined with the help of Excel software and the comparisons were done with independent t-test through Spss software.
Findings: The total number of harvested plants was 351, which is equal to the floristic characteristics of the sampled plants. The results showed that they belong to 19 plant families, which include four tree families (maple, hemrose, parsnip, and alder) and 15 grass families (of which 5 species are abundant. It includes: Jagen, Ferfion, Raspberries, Banafsheh, Matamati). Of all the sampled plants, 22% were found in the two sliding areas and 78% were found in the control areas. The plants harvested in the landslide areas were 87 pieces, all of which were herbaceous plants and there were no woody species among them. The findings regarding the difference in the growth status of plant species between the sliding areas A and B with the control and adjacent area, according to the paired comparison, the number of species and the abundance of plants were strongly affected by the disturbance caused by the sliding movement. They had a decreasing trend compared to the control areas and the results were statistically significant at 95%.
Conclusion: The creation of disturbances such as shallow landslides causes a significant decrease in the number and diversity of plant species, so that in the landslide area, native plants have not been established and restored according to the model of the control area, and 10 herbaceous species Such as cyclamen, primrose, sedum, fern, zebrina, etc. were not observed after the slip. And considering the absence of tree species in the landslide area, despite the passage of 6 and 8 years since the landslide occurred, the negative impact of the disturbance caused by the landslide on woody species is quite clear, but in The grass of this establishment, although in a small way (compared to the control area), is being restored and restored naturally. It is noteworthy that fast-growing herbaceous species such as jagen, farfion, and raspberry were established earlier than other species in the two studied areas, and the manner of competition, seed distribution, germination, number of seeds, physiology, ecophysiology, and other characteristics of these species may have been effective in their success in occupying the landslide areas. It was also found that about half of the plants in the area (before the landslide) did not return to the area, especially woody plants, at least in the short term, according to the observations of the control areas.
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