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Nowadays, academics have paid special attention to global warming, because it has several issues such as urban heat island (UHI) related to the quality of life. For this purpose, a spatial decision support system (SDSS) has been developed to investigate the effect of parcels' roof covering type on surface heat island (SHI) values and its variation at the neighborhood scale in Tehran, Iran. This SDSS, as the innovation of the present research, consists of two main steps including estimating the UHI value in the study area and adopting the optimum set of parcels to change their roofs' cover with three types of vegetation, high-albedo material, and flagstone. The first step is accomplished by aggregating various indices related to land cover obtained from Landsat 8 images. The aggregation is done by linear regression method (LRM) with an RMSE and R2 equal to 0.942 and 0.897, respectively. Then, the genetic algorithm was used to select the optimal subset, including 10% of the parcels in the area, to change their roof covering type based on minimizing the UHI's variation. The standard deviation obtained after the changes improved from 13.222 to 10.781 °C. The results indicate that to control UHI in the center of the region, it is necessary to inhibit UHI effects at the boundary of the study area with vegetation roof covering since flagstone and high-albedo materials have local effects on controlling the UHI effects. [ABSTRACT FROM AUTHOR]

It has often been stated or implied that grazing is an important factor in the land degradation process, a suggestion supported by various research projects, and this study investigated the effect of livestock grazing on stem height, crown cover, production, basal diameter, stem biomass, litter, leaf-stem index (leaf to stem weight) , root diameter and weight and seed production per individual of the even-aged Atriplex canescens , by comparing two sites (grazed and non-grazed) across Zarand, Shahreiar rangelands located in the southwestern of Tehran, Iran. For this purpose, by using systematicrandom sampling method, four 300 m long transects were set up in each sampling area and ten quadrats were randomly assigned per transect [8] to measure the stem height as well as the crown cover, production, basal diameter, stem biomass, litter, leaf-stem index , seed production per individual and root biomass and diameter were measured at 3 soil depth (0-30, 30-70, >70 cm) with 4 replications within each of the two studied sites, results indicated that, grazing had no significant influence on stem height and leaf-stem index but crown cover, production, basal diameter, stem biomass, litter, seed production per individual, root weight and diameter of the even -aged Atriplex canescens were significantly greater than those of the un-grazed site. [ABSTRACT FROM AUTHOR]