h. ghazanfari

One of the problems of Zagros forests is the phenomenon of oak dieback, that its control is one of the important factors to prevent the destruction of forests. One of the proposed solutions to control this phenomenon is implementation of sanitary cutting. Remote sensing data has made it possible to monitor the areas involved in this phenomenon. The purpose of this study was to investigate the spectral behavior of exposed dieback forests before and after sanitary cutting in Guilan_e_Gharb forests. To monitor the pattern of spectral behavior, Landsat 8 satellite images were used from one year before sanitary cutting (2013) to 2018. After atmospheric correction of satellite images, NDVI, WDVI, SAVI and NDWI vegetation indices were prepared using spectral ratios of the main bands. A total of 30 points were selected scattered throughout the region and the spectral value of near-infrared band and vegetation indices were extracted at the selected points. The results showed that the spectral behavior had an upward trend until the last year of monitoring. The results of comparison of means test on the data of 2013-2018 showed that the differences between the means of all bands were statistically significant. Although the spectral behavior of vegetation indices is also affected by climate change and rainfall, but due to the increasing trend of near-infrared and vegetation indices during the years after sanitation cutting, a large part of the changes can be contributed tothe result of sanitary cutting and improvement of the forest conditions.

The aim of this study is to investigate the quantitative changes in the biometric indices of Lebanon oak (Quercus libani Oliv.) and gall oak (Q. infectoria Oliv.) during pollarding process. In a part of the two pollarded strands in northern Zagros of Iran, in which three years had passed from its last pollarding, the name of woody species was recorded and diameter (dbh), total and crown heights, and two perpendicular crown diameters were measured before and after pollarding in a full callipering assessment of all trees (dbh ≥ 5 cm). The results showed that in the pollarding process, crown height and crown area of oak trees decreased on average 15.73 and 30.06%, respectively. In both studied species, the reduction of crown area is significantly more than the crown height. In terms of reduction in crown height and crown area, there was no significant difference between Q. infectoria and Q. libani trees. The most decrease in crown height (27.99%) and crown area (44.85%) indices on diameter classes are related to Q. infectoria trees belonging to the 35 cm diameter class and Q. libani trees belonging to the 55 cm diameter class, respectively. The results indicate a higher decrease in the crown area compares to the crown height of oak trees due to pollarding practice; therefore, it is necessary to partially compensate for this decrease in the crown area by leaving some branches during each pollarding operation, because preserving the canopy is very important for Zagros-forest ecosystems. The only way to conserve these resources is to create a participatory approach as part of the transitional forest policy.

This study was carried out to analyze the performance of natural resources cooperatives in Paveh County, Iran. Cochran’s formula was used for determining the population sample size among members of active cooperatives in the study area. Data was collected using a fully structured questionnaire whose validity confirmed by both faculty members of university and cooperative organization experts. Cronbach’s alpha coefficient estimated through a pilot study was used for measuring the reliability level of questionnaires. Correlation analysis and stepwise multiple linear regression were used to analyze the data. Pairwise comparisons indicated that social, economic and environmental factors were respectively the most important criteria contributing to cooperative successful performance. According to results, all independent variables displayed significant positive correlation with success of cooperative, so that factors transparency of organizational duties and belief in teamwork were maximum and minimum correlated factors from cooperatives members’ viewpoint. Regression analysis revealed that some factors were significantly influenced the performance of cooperatives. Five independent variables were entered into performance model of cooperatives which transparency of organizational duties with a standardized beta coefficient of 0.305 was the most important variable influenced cooperative performance. Relative success index indicated that performance rate of all cooperatives was lower than 50% (minimum 33.8 and maximum 44.6%). The results of this study can be used to identify the strengths and weaknesses and planning actions needed to rebuild and reactivate the cooperatives.

Local economy, based on animal husbandry in Northern Zagros forest leads to increase employing leaves and branches (pollarding) compared to the other parts of Zagros. Pollarding is a convenient method in forest utilization to supply fodder and it has been always trying to obtain its stable production by proper management skills. One of the most important forest management tools in a given forest is to provide up-to-date spatial maps of pollarded regions. The objective of this study was to investigate the capability of multi-temporal Landsat 8 OLI sensor for mapping pollarding areas of Northern Zagros forests. So that, we employed Landsat 8-OLI single and multi-date images acquired on 2014 and 2015. To assess the accuracy of output maps, a complete ground-truth of the study area was used to calculate the accuracy heuristics for the output maps. Different classification approaches were applied including minimum distance and maximum likelihood classifiers, artificial neural networks and fuzzy method. The classification accuracy was calculated on the basis of overall accuracy and kappa coefficient. The results indicated that artificial neural network and fuzzy classifier present the highest accuracy than the other classifiers. It was also found that utilizing the multi-temporal OLI imageries improves the accuracy over employing a single date. The results indicate that the multi-temporal imagery is moderately capable of mapping pollarded stands and classifying pollarding types, using ANN and Fuzzy classifiers.

One of the oldest traditional usages of forests is cutting the branches for fodder production. In Iran in some regions of northern Zagros some species specially Lebanon oak (Quercus libani Oliv.) is used to provide fodder. For this reason each family normally has a forest region to meet cattle's fodder and fuel wood by cutting tree branches. Since trees could record this phenomenon in their tree rings, in this study we tried to investigate the tree rings by using of Dendrochronology to understand the effect of human activity like cutting branches on tree rings formation. According to this idea, two stands of oak forests that located in regions near the village and regions that located in low human interruption (holly places like cemeteries) have been selected. Twenty thick and healthy trees were selected from each region and samples were taken in the shape of disks and increment cores. After preparing samples surface, ring width of the trees were measured by binocular and LINTAB measurement table with 0.01 mm precision. Cross dating have been done using TSAP software. Growth curves of trees in interrupted region showed significant growth reduction in comparison with growth curves of trees in preserved region. In addition, this type of usage of forests will change the normal growth form of the trees and will increase the negative pointer years as an index of the radial growth reduction in interrupted region. It looks that the severity of this traditional way of cutting branches is increased during the last 100 years.