saeid shabani

Forest fire in many ecosystems is a natural phenomenon, but also a serious and dangerous threat with environmental, ecological, and physical effects. Therefore, this research investigated the risk areas of fire in Zagros forests identification to evaluate the changes in the time series of deals with a potential fire hazard. To achieve this goal fuzzy layers of analysis network process and order weighted average method were used regularly. For this purpose, fire Zagros forests using satellite images Landsat and MODIS Lordegan city in the period between 2000, 2007, and 2014 and the factors affecting fire are examined. The high-risk areas based on classification utility area and the number of zones were identified as fire-prone areas. In the analytical network process procedure, the largest weighs were assigned to the distance from residential areas and roads, GVMI index, and maximum daily air temperature factors which were 0.209, 0.198, 0.09, and 0.0716, respectively. Time series analysis map showing the extent of critical areas from 2000 to 2014 decreased by investigating the factors affecting fire occurrence in critical areas, distance for roads and residential areas, slope, aspect, GVMI index, and NDVI and maximum temperatures have the greatest impact were on fire. The low-risk scenario and a small amount of compensation with the ROC higher than 0.7 as the best model was the estimated risk of forest fires. The preparation of a map of areas susceptible to fire, as well as analyzing and analyzing the time series of factors affecting the fire in different years, is an effective step in helping forest managers to plan and implement preventive operations in high-risk areas.

Plant Species Richness (PSR) plays an important role in forest ecosystem functions and services. Despite the fact that Fine Woody Debris (FWD) occupy a large volume of the temperate forest ecosystem in the north of Iran, they have received less attention than Coarse Woody Debries (CWD). FWD is a component of natural forests, in addition to increasing the productivity of forest trees, helping to trees regeneration, maintaining and increasing soil moisture and nutrients, and long-term carbon storage, contribute the enhanced function of newly developing microhabitats with an important function in plant understory richness. Therefore, not paying attention to FWD leads to wrong estimation of the total volume of woody debries and its key role on the performance of forest ecosystems. Therefore, it was considered for current study that Boosted Regression Tree (BRT) machine learning technique used to model the PSR in unmanaged forest stands. For this aim, Oak - hornbeam stand in Loveh forest in the east of Golestan province, Iran was selected for sampling.

For this purpose, 30 sample plots 400 m2 (20 m × 20 m) were set in the study area, and the type and percentage of plant cover was recorded based on the Braun-Blanquet index. In the following, the number of plant species recorded in each sample plot was the basis for calculating species richness. In order to measure the volume of FWD, the alignment of the sides of the sample plot of 400 square meters was used as the basis of calculation. Therefore, in line with the sides of each sample plot and in the form of a linear transect with a total length of 80 meters (equal to the perimeter of each sample plot), FWD intersected with the transect were identified. The names of tree species of each of the FWD is specified, and according to the cross diameter with the transect, the FWD were placed in one of three diameter classes: 1 to 2.5 cm, 2.5 to 4.5 cm, and 4.5 to 7.5 cm. To measure the percentage of soil moisture and organic matter, the soil was taken from the center of each sample to a depth of 15 cm. Soil moisture percentage was obtained by using the difference between wet and dry weight of soil and also the amount of soil organic matter by Walkley-Black method in the laboratory. The gmb package in R programming language was used to fit the boosted regression tree model. This model is one of the methods that helps to improve the performance of a single model by using the combination of multiple models. Therefore, in this method, the combination of two algorithms "regression tree and classification" and "boosting" is used. It should be noted that in this research, in order to reach the optimal number of trees, the number of 1000 was used as the starting point. In this study, the amount of species richness in each plot as the response variable, and the variables of slope percentage, slope aspect, altitude, soil moisture percentage, soil organic matter percentage, average of total volume of fwd, average volume of fwd in decay class 1, average volume of fwd in decay class 2 and the type of fwd were considered as predictor variables.

Based on the results, the initial model fitted in the number of trees 7700 showed the highest accuracy. However, due to the lack of influence of some variables in the model, the variables of slope, slope aspect, altitude, the type of fwd and the average volume of fwd in decay class 1, these variables were excluded from the model based on the deviation changes. And the model was refitted in the optimal number of trees of 7800. Based on the final model of the BRT, the highest amount of species richness was recorded with the increase of soil organic matter to > 2.15% and in a soil moisture percentage >30%. Furthermore, a high amount of FWD from the first diameter class and with the decay class 2 (rotten) led to an increase in plant richness in the studied area. In the present study, the adjusted R squared > 0.99 with the Root Mean Square Error (RMSE) < 0.039 shows the high accuracy of the BRT model.

Although fwd comprise a large part of woody debries in the forests of the north of Iran, no specific place has been considered for it in any of the statistical protocols. This matter has led to the fact that there is no specific estimate of the volume of fwd and its role on the forest ecosystem is neglected. Therefore, this study was conducted with the aim of modeling the effect of this important component on the richness of plant species in a broadleaf stand in Loveh forests of Golestan province. The findings of the research showed that by creating favorable habitat conditions, the fwd increase the abundance of plant species and maintaining this component is important in increasing the organic matter of the forest soil. The high rate of decomposition in fwd compared to cwd causes that while maintaining and increasing the soil moisture, the organic materials in the wood are available to the soil layer in a short period of time. In recent years, some experts in the field of natural resources have emphasized the collection of fwd and their use in cellulose industries. A large part of these opinions has also found a scientific basis in the shadow of the minimization of the volume and role of the fwd and the lack of sufficient information about this very important component. If the findings of this research clearly show that the collection and removal of fwd will have a negative impact on soil moisture and organic matter and thus on the richness of plant species. Conducting similar and additional studies by including soil nutritional variables as well as other plant indicators can significantly help in confirming or rejecting this result

Hyrcanian boxwood (Buxus hyrcana Pojark.) is an evergreen tree and native to the Hyrcanian forests in northern Iran, which is considred as one of the endangered plant species. In vitro propagation of this valuable species can prevent its extinction. The presence of fungal and bacterial contamination is one of the main challenges of in vitro culture of Buxus hyrcana, which can affect the propagation of this valuable species and on the other hand, can lead to many costs. In the present study, the efficacy of 15% Percidine, Aqua Percidine, Super Percidine and Percidine Plus in removing contamination from B. hyrcana explants was investigated under in vitro culture conditions compared to the usual method (using sodium hypochlorite).

The experiment was performed in factorial arrangement as a completely randomized design with 3 replications. First, for pre-treatment, explants (twigs and seeds) were washed with ordinary water and a few drops of dishwashing liquid for 5 minutes to remove surface contaminants. Then, they were placed in benomyl fungicide (1%) for 10 minutes. After washing, under laminar airflow, sterilization of explants was performed with experimental treatments. Experimental treatments included disinfectant (Percidine 15%, Percidine Aqua, Super Percidine, Percidine Plus (at concentrations of 0, 1, 2, and 4%) which were compared with sodium hypochlorite. After sterilization of the explants, the plant materials were placed on Murashige and Skoog medium. To measure contamination, cultures were examined under growth conditions at 25±1 °C with a light intensity of 1000 to 1500 lux (16 hours light and 8 hours dark).

The results showed that fungal and bacterial contamination in the seed explant was significantly reduced compared to the twig explant. On the other hand, Super Percidine sterilizer showed high efficiency (63%) in the twig explant in reducing contamination from culture medium. Moreover, in seed explants, in addition to Super Percidine, Aqua Percidine sterilizer also showed high efficiency in reducing contamination from seed surface (33%).

Therefore, it seems that the use of Super Percidine (2%) sterilizer can be useful for twig explants and both of Super Percidine (2%) and aqua Percidine (2%) is suitable for seed explants.

Global forest area has decreased by nearly 180 million ha in three decades. So, many ecosystem services provided by forests have been threatened. Reforestation and afforestation are the most effective strategies for mitigating deforestation. Therefore, in a variety of countries worldwide, including Iran, several afforestation projects have been implemented; however, the quantity and quality of many afforested lands have decreased over time under the influence of catastrophic factors, environmental stress, and different management methods. Awareness and continuous monitoring of forest programs are some of the most fundamental forestry policies. Therefore, the monitoring of annual afforestation in the eastern Golestan province using Google Earth software was put on the agenda to prepare an afforestation map and identify the reasons for the success and failure of the implemented plans. According to the findings, 19,377.39 ha of afforestation have been planted in Golestan province. Of these, Maraveh Tappeh city has the highest amount of afforestation with more than 9,256 ha with C. arizonica L, C. sempervirens L. var. horizontalis (Mill.) Gord. and P. brutia Ten, mostly. The presence of suitable climatic and edaphic conditions in the Golidagh of Maraveh Tappeh City and the ArabDagh area of Kalaleh City played a prominent role in the success of artificial forests in these areas. It should be noted that wood smuggling, the presence of livestock, the occurrence of fires, the presence of natural and human obstacles, and continuous monitoring have been other factors affecting the success or failure of afforestation programs in the eastern Golestan province.

In order to manage the forests and optimal and sustainable utilization of the forest, it seems necessary to know the information on the volume of the residual stand. In this study, a systematic randomized inventory was carried out in 186 circular 10-acre plots in the educational and research forest of Darabkola, Sari, Golestan, Iran and the volume of each plot was obtained. In the next step, the physiographic layers of the area were prepared using the topographic map and the vegetation characteristics were prepared using the LISS-III image of the IRS-P6 satellite with a resolution of 23.5. After preparing physiographic layers and vegetation characteristics, their value was calculated for all plots. Then, regarding these variables and using two methods of multilayer perceptron neural network and multiple regression model, modeling was done. The results showed that the multiple linear model could model the volume changes in the region with higher accuracy (R2=0.75 and RMSE=0.3). The results of this research can be used in management planning and as one of the effective factors in the design of logging routes and forest roads so that areas with larger volumes are covered more.

Dead trees protection, has a key role in structural and biogeochemical processes in forest ecosystems. Some aspects of dead tree dynamics have been carefully studied, but the kind and decay degree of dead trees and forest soil properties have not received enough attention. The aim of this research was to study the effect of a kind and decay degree of dead trees on soil mineral properties in the Sarcheshmeh Forest, Chaloos. For this purpose, the dead trees were investigated by strip transects with 10 m width and 80 m distance between transects. 71 dead trees were identified. In addition to determining kind of species, dead trees were categorized into four decay classes consists of a new dead tree, decay beginning, advanced decay, and perfect decay. The Soil sampling for estimating total nitrogen (%), available phosphorus (ppm), K (%), pH, soil moisture (%), carbon (%), C/N, and biomass of earthworm (g) was carried out in the closest position to the dead tree in 0–30 cm depth. Principle Component Analysis (PCA) method and analysis of variances were used to compare the relationship between dead trees and soil properties. The results showed that there was a strong relationship between carbon and C/N values with oak dead trees. Soil nutrients, pH and soil moisture (%) have displayed a significant relationship at the 5 percent probability level with alder and hornbeam dead trees. The fourth decay class had the most values of N (0.76%), P (15.53 ppm), and earthworm biomass (26.61 g), whereas there is no significant difference between first and secondary decay classes. The K (%), pH, and soil moisture (%) values were increased from first to fourth decay classes. Based on the findings current study on the key role of dead trees in forest soil richness, the dead trees should be protected during forestry operations in each forest ecosystem to sustain soil productivity.

China has made significant progress in the implementation of international obligations in its domestic legal system over the past thirty years. However, the Chinese constitution and ordinary laws do not lay down general rules on the status of treaties in the domestic legal system. But the substantive obligations of the treaties to which China has acceded largely to domestic law and directly affect the country's economic and social activities. This article examines the various forms and ways in which China implements its international commitments domestically. In line with this, the number of cases in which courts use treaty rules is increasing, indicating China's determination to adhere more fully to its international obligations. In civil and commercial matters, international treaties apply primarily to cases with foreign elements, while in criminal law, China has placed almost all international crimes as criminal offenses under its national criminal law. And over the past thirty years, there has been significant progress in the implementation of international obligations in its domestic legal system. This article illustrates the various forms and ways in which China implements its international obligations at home, given China's position in the international system.

Dead trees are an important factor for structure and activity controlling in forest temperature. For the sake of survey role of dead trees in the regeneration of trees species, regeneration density of environs dead trees in Lalis forests, Nowshahr was studied.

For a sampling of snags by circle plots (500 m2 area) and snag in the center, and also in the logs used of along plots into width four-meter and dead trees length. Decay classes of dead trees, topographic position and canopy gap area due to dead tree inscribed according to average diameter of canopy opening. In this study gaps were divided into five groups, including close canopy, very small (<50 m2), small (50-150 m2), medium-size gap (150-250 m2) and large size (250-480 m2).

Results of regeneration show that beech species had the most regeneration density. According to the results of density in decay classes, the fourth class had the most regeneration density for total species. Also with the increase in the size of gaps area, accrue in regeneration density and fifth class includes most regeneration. Differences mean values of density between slope and altitude classes weren't significant, but the density of Beech, Persian Maple, Cappadocian Maple, and Alder species were significant in different aspects.

The findings of the present study show that recognizing natural processes in virgin stands of forest ecosystems provides useful information for managers to make the right decisions.

In this article, effects of DC stray current on concrete structures were studied in chloride free environments. In this article, effects of potential of DC stay current on permeability of concrete in chloride-free aqueous medium were studied. For this purpose, concrete samples with different w/c ratio and silica fume content were subjected to 50 VDC in distilled water for 30 days. The effects of DC stray current on the properties of concrete were determined by resistivity, Electrochemical Impedance Spectroscopy (EIS) and electrical permeability test. The results clearly showed the negative influence of DC stray current on the permeability of the concrete. The critical role of w/c ratio and silica fume additive on the degradation effects created by DC stray current was revealed. Migration mechanism of Ca(OH)2 of concrete under DC stray current was proposed. This process increases pores sizes distribution and creates new pores network in concrete and so increases its permeability. Decreasing w/c or adding silica fume to concrete mix design increase stability of concrete against increasing its permeability by effects of DC stray current.