FOREST RESEARCH AND DEVELOPMENT
Year:2018 | Volume:4 | Issue:2 |Papers Count:9

Today, natural vegetation is severely damaged in many arid regions due to different causes. This phenomenon leads to desertification in these areas. Afforestation by planting seedlings is one of the approaches to the prevention of desertification by planting suitable plant types (such as Nitraria schoberi L.). One of the effective factors in seedling quality is physical-chemical soil substrate properties. The aim of this research is to investigate the effect of soil substrate on vegetative properties of Nitraria schoberi seedling in nursery based on completely randomized design including seven soil treatments with four replications in Zirkouh nursery in the spring of 2013. The results showed significant effects of different soil treatments on different growth properties of Nitraria schoberi L. seedlings. Based on the results of this study, mixture of clay soil, sand and animal manure (1:2:1) can be suggested as the best soil substrate in order to growth of Nitraria schoberi L. seedlings in the study site and the similar areas. Using this soil composition is recommended for the purpose of production of high quality seedling in nursery, with ecological conditions similar to this research.

The aim of this research was to assess the effect and range of each forest road geometric plans on biodiversity and composition of plants on its two sides. To this end, to study the biodiversity of species of lateral stands and the effects of environmental variables in the situation of establishment of plant species at different distances of the road, the comparison of Shannon biodiversity Index (H), Menhinick species richness and Smith-Wilson’s index of evenness, detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used respectively, according to its geometric plans. Results of the comparison between biodiversity indexes showed that in both sides of the straight road to switch back, Shannon index and Menhinik richness increased, while Smith-Wilson evenness had an inverse trend. The results of DCA and CCA analysis showed that the distribution of demanding species was positively correlated with increasing light intensity and temperature on the road verge. The effect of the road on these species was up to a depth of 10 meters from its edge as well. Shade tolerant species were more in-depth of forest than the road.

The study aims to identify and assessment appropriate criteria for sustainable management and their prioritization in the Zagros forests of West Azerbaijan province. In this regard, First, by collecting and reviewing the views of all those involved in forest management using non-inferential sampling method and using a questionnaire, the criteria of the study area were determined. The statistical population related to the determination of criteria was about 68 people. Then, selected criteria has been of based on the organizational approach, were evaluated according to the opinions and approvals of experts (about 35 people) in the four fields management, overhead institutions, social and laws and political. Evaluation was performed based on SWOT analysis approach to determine the internal factors (strengths and weaknesses) and external factors (opportunities and threats) selection criteria in each four areas, and prioritization of the criteria using pairwise comparison analysis and Super Decisions. Based on the results of SWOT analysis from a total of 91 selected criteria, for the management area of 35 criteria, the overhead institutions area of 21 criteria, the social area of 11 criteria and the laws and policies area of 24 criteria were accepted. Prioritization results showed that in the management area criteria of "top-down decision making" with a weight of 0.96, in the area of overhead institutions, the criteria “dependent and subsistence of the forestry organization in the Ministry of Agriculture" with a weight of 0.158, in the social area the criteria of "undeveloped social, economic and cultural attributes of the region" with a weight of 0.199 and in the laws and policies area, the criterion "lack of land use and of talent selection systems" with a weight of 0.114 was more important.

Reaction vegetative growth and yield of 7-year-old trees of three eucalyptus species (Eucalyptus camaldulensis, E. microtheca and E. sargentii) to coppicing and coppice production which damaged by frost, were studied. Trees had been planted under Yazd climate conditions and they have been irrigating with wastewater. The species were used in this experiment; planted in 2007 for compatibility testing in a randomized complete block design with three replications and 36 plants per each block. All trees were damaged by frost in 2013. In the spring, trees were cut by a chainsaw at a height of 15 cm from the soil surface. After three months of coppice growth, the number of coppices were reduced to three in each trunk. After three years, results of coppicing and thinning of coppices were evaluated on six plants in each block that they were selected randomly. For evaluating production ability of coppice on each trunk, all plants in each block were investigated. The results showed that between the coppices of species were significant difference (P<001) in the number of basis after coppicing. E. microtheca had the most of basis with 80.26 percentages. Diameter equations and height of coppices in all of species had significant difference (P<001). Coppices canopy diameter, surface canopy, volume and percentage canopy had significant difference (P<05). E. camaldulensis coppices had better characteristics than other species. In some cases, such as coppices canopy diameter and canopy surface were not significant difference between E. camaldulensis and E. sargentii.

The forest type map is one of the most important thematic maps for forest ecosystem management. Forest mapping using field methods or aerial photos is labor-intensive and time consuming. In contrast, satellite data with its own characteristics like large and repetitive coverage, update and useful information in various wavelengths provides a good opportunity in this regard. This research was carried out with the aim of providing forest type map of central Zagros forests (Chahartagh forest reservoir), of Iran, using the Landsat 8 Operational Land Imager (OLI) data, in August 2016.Two ground-truth maps based on tree density and tree crown area were prepared by field surveying. Moreover, ancillary data such as tree species, location and crown area was taken. In order to increase the spatial resolution of multispectral bands, various image fusion techniques were applied. The best result obtained by the maximum likelihood algorithm with kappa coefficient and overall accuracy values of 57 and 63%, respectively. Due to high species diversity in this area the results showed that the OLI images have a moderate capability to produce forest type maps in Zagros forest.

This study explores the relationship between diversity of herbaceous understory of forest types with tree layer as well as some edaphhic factors in central Zagros. To do this, tree layer of the forest types were randomly sampled using 24 sample plots (500 m2) and herbaceous understory of these forest types were randomly sampled using 288 sample plots (1 m2) at the growing season. In main plots (tree layer), in addition to physiographic features, density, coppice shoots and tree canopy area, soil variables were measured from soil samples taken from the depths of 0-10 and 10-30 cm. In plots sampled from herbaceous understory (1 m2 plots), in addition to measuring species richness, the percentage of species was recorded as an indicator of the abundance. Results showed that the values of richness indices (total richness, Menhinic, and Margalef indices) and diversity indices (Shannon-Wiener and Alpha Fisher diversity) of herbacious layer in Quercus infectoria Oliv. Forest type was significantly higher than Q. brantii Lindl forest type. No difference was found among these types in terms of indicators of dominance, evenness and Simpson diversity indices. The results of Pearson correlation indicated that the richness and diversity indices of studied forest types is positively correlated with soil clay, silt, lime, calcium and acidity.

The study of forest structure is one of the basic requirements to achieve the objectives of close to nature silviculture. The purpose of this study was to identify the structural characteristics of coppice forest stands in Fandoghlou forest, Ardebil province. Three representative sites were carefully selected after detailed field survey. In each site, 3 sample plots with one hectare area (100×100 m) were established according to a random systematic design. In addition, in each sample plot, 25 subplots (4×5m) were determined for regeneration study. In each microplot, the frequency of regeneration was recorded in different diameter and height classes. Data were analyzed using appropriate softwares (Excel and SPSS). Results showed that, Fagus orientalis Lipesky, is the dominant species in one of the sites and in two other sites, beech accompanied hornbeam and hazelnut. The situation of stand structure and regeneration in site one and two were better than site three. Distribution charts of number in diagonal classes showed uneven-aged and irregular stands. Mean comparison of structural parameters in studied sites showed a significant difference at 5% confidence level for various sites.

Nowadays, the expansion of human societies and greater environmental dominance have caused more rapid and wider environmental changes to take place. This will reduce the scope of the natural arenas and increase its dispersion and termination. The aim of this research is to evaluate the time variation and spatial distribution of the Piranshahr land plots with the help of remote sensing and land surveying in a ten-year time horizon, which is important for current and future planning of land use for sustainable development. Landsat satellite images were used to prepare land use map. In order to investigate land use changes during this time interval, Fragstats software was used to measure the Number of Patches, Patch density, percentage of Lands, Largest Patch Index metrics in the class level, and the number of patches, patch density, Shannon,s diversity and contagion metrics in landscape level. The results of the research using the metrics at two levels indicate that, in general, the shape of the fragmented landscape is more complex, irregular, and in terms of the integrity of the structural elements, the more discontinuous (from 39.01 to 33.06%) and in terms of type The use of coverage in a more diverse area (from 1.04 to 1.15) has been used.

In forest areas outside of northern Iran, Establishing forest roads is costly and without revenue, and is often performed by Jihad-e-Sazandegi and Roads and Transport institutions with the purpose of accessing development projects such as dams or electricity transmission, water supply, access to rural areas, etc. Considering the priority of socio-economic issues in western forests of the country, evaluating the impact of forest roads on the development of services in villages is necessary. For this purpose, in the present research, the trend of development of forest road network in the 40s, 80s and 90s was determined by calculating the length of the road and assessing the quality of the pavement. To do this, photographs of the aforementioned decades were obtained from the Mapping Organization of the country and after geometric corrections, the images underwent visual interpretation. Then, by using statistical resources and information about the general census of population and housing, and completed questionnaires for each village, the development of the villages of the study area was estimated via the Z index in the mentioned time intervals. Then, route access and rural development were calculated using Spearman correlation test. The correlation coefficient was obtained 0.738, which shows a direct and significant relationship between access to forest roads and rural development.