مجله تحقیقات حمایت و حفاظت جنگلها و مراتع ایران
سال سیزدهم شماره 1 (پیاپی 25، بهار و تابستان 1394)

Fire is one of the most destructive factors in forests. This research was carried out to investigate the impact of climatic factors on fire in Golestan forests. Statistics of the area and the number of fires in Golestan forests in the two past decades (from 1990 to 2010) was provided by the Golestan Natural Resources Administration and the climatic data of the two past decades was provided by the Golestan Aerology Administration. Climatic data with the mean annual temperature mean annual precipitation and mean annual relative humidity in the four stations was obtained to get the mean climatic data of Golestan Province. Then the flowchart of the climatic data was drawn. After normal testing of data، Pearson’s correlation coefficient was used to explore the relationship between climatic data and fires. Data analysis was performed using SPSS. Statistical analysis s of climatic data based on Pearson’s correlation coefficient showed that there was a significant relationship between number of occurred fires in Golestan forests and mean annual temperature with a 95% confidence level and also between the number of occurred fires in Golestan forests and mean annual relative humidity with a 99% confidence level; but there was no significant relationship between the number of occurred fires in Golestan forests and mean annual precipitation. On the other hand، there was a significant relationship between the area of occurred fires in Golestan forests and mean annual relative humidity with a 95% confidence level، but there was no significant relationship between the area of occurred fires in Golestan forests and mean annual temperature and mean annual precipitation. The overall results showed that there was a direct relationship between fires of Golestan Province and the mean annual temperature، and there was an indirect relationship between fires in Golestan Province and mean annual relative humidity.

Logging operation due to soil disturbance and compaction changes soil physical and chemical properties. On the other hand، there is a paucity of data on the time required for recovery of disturbed soil properties. This research was therefore carried out to investigate the effects of ground-based skidding on organic matter، which is one of the important chemical soil properties، and it''s process of recovery over a period of 10 years after timber skidding. Changes in organic matter was quantified at three traffic levels including low، medium and heavy on a skid trail that has recently been established. Three skid trails have been left without skidding and traffic for one، five and ten years. The results indicate that skidding with regard to traffic intensity، when compared with the control، significantly decreased organic matter by 32. 5، 53. 5 and 58. 5% at low، medium and heavy traffic، respectively.. Furthermore، the rate of recovery with regard to traffic intensity varied depending on degree of soil disturbance، where low traffic showed more recovery than medium and heavy traffic. The results revealed that soil organic matter removal by skidding was beyond the disturbance threshold and even after a ten-year period، no complete recovery was observed.

Stresses caused by recent droughts and fine dust lead to physiological weakness of oak trees as the insect outbreaks and pathogens lead to oak tree decline in the Zagros forests. To evaluate the effect of physiographic factors (terrain relief)، forest cover density and soil on the amount and distribution of dead standing oak trees، a logistic regression model was used. An area of 540 ha of oak forests in the Bivareh region from Malekshahi country in Ilam province was selected. Global positioning system was used for recording all dead standing oak trees. Then، using the recorded points of dead standing trees and digital elevation model، different required maps of the study area like distribution map of dead standing oak trees، elevation classes map، aspect and slope percentage maps، forest density map and soil map were developed. In order to understand the relationship of each factor with dead standing oak trees a logistic regression model was used، with the maps of aforementioned factors as independent variables and the map of location of dead standing oak trees as the dependent variable. The results showed that with increasing altitude in the western and southern aspects، increasing forest cover density and in areas with shallow soils and steep terrain the amount and distribution of dead standing oak trees were increased. Finally، based on the current position map of dead standing oak trees، the effects of independent variable probability maps of dead standing oak trees for the future was produced.

Outbreak of charcoal disease caused by Biscogniauxia mediterranea (De Not.) Kuntze، have occurred periodically in oak forests of Iran in recent years. This study was performed to investigate the relationship between some environmental variables and charcoal epidemic disease during the years 2013 - 2014 at chestnut leaved oak trees in the national park of Qoroq in Golestan province. For this purpose، the health status of 385 trees were examined in seven transects with 102 nodes. The results showed that 25. 8، 14. 4 and 59. 8 percent of the selected trees were not infected، completely dried or with different infection levels، respectively. The infection rate and severity of the damage increased more in the old trees than the young; however، the mortality rate was higher than in the young trees. Overall، the mortality rate and infection of the oak trees in the study area were 49. 5 and 1. 5 percent per year، respectively. The results showed that elevation and slope were the main factors affecting the severity distribution and infection rate of charcoal disease. Outbreak of charcoal disease had profound adverse effects on the structure of oak forests، and this was influenced by environmental variables. Finally، preparing the epidemic models of disease requires an understanding of how environmental variables influence the interaction between host and pathogen. The findings of this study may provide an appropriate model for the management and control of the charcoal disease and provide protection and restore the forest ecosystem.

This study was conducted to identify the arbuscular mycorrhizal fungi in the roots and rhizosphere of Amygdalus scoparia in the forests of Kolm reservoir in Ilam province. Therefore، in the rhizosphere of almond trees، soil and root samples were collected from a depth of 0-30 cm. Soil samples for isolation and identification of fungi were transported to the laboratory and spores of arbuscular fungi were isolated using the wet sieving and decanting method on Sucrose followed by centrifuging. Isolated spores were mounted on slides and Spore morphological characteristics were considered for identification. In total، 13 species belonging to 7 genera of arbuscular mycorrhizal fungi including Funneliformis، Acaulospora، Gigaspora، Septoglomus، Diversispora، Claroideoglomus، Rhizophagus، were identified in the rhizosphere of almond trees. Rhizophagus was the dominant genus at 30. 8 percent. Further، the Funneliformis caledonius، F. mosseae، Rhizophagus intraradices، R. fasciculatus، R. clarum، Claroideoglomus drummondii، Gigaspora gigantea were the most and C. etunicatum was the least found species in the area. Most abundance of spores belonged to the Funneliformis mosseae species.

Assessing the structure and functionality of rangelands is required to detect early changes in the ecosystem and assist managers to evaluate the effects of their management practices. This study was aimed to evaluate the functionality of steppe and semi-steppe rangelands in Isfahan province using field and remote sensing approaches. For this purpose، the functionality and land degradation status in 50 sub-basins were identified using the field- based landscape function analysis (LFA) method in 15 sites in steppe rangelands of Shahreza in south of Isfahan with very poor conditions، and also 21 sites with very poor، poor and moderate conditions in the semi-steppe rangelands of Aghcheh in west of Isfahan. The remotely- sensed leakiness index (LI) was calculated on the basis of the 50 sub-basins and a DEM map of the study area and also NDVI and SAVI vegetation indices were extracted from Landsat TM images in June 2009. The results showed that the outputs of the LFA method had positive and negative relationships with vegetation indices and LI with a 95% confidence level (P-value<0. 05)، respectively. Hence، in broad arid and semi-arid rangelands of Iran، these functionality indices can be used to prioritize rangeland functionality levels and protect these natural lands from degradation in the future using appropriate monitoring programs at the sub-basin scale.

Pollinators and seed predators may strongly influence some of the plant reproductive fitness measures. For supporting conservation and development of the plant species with local dispersal، identification of favorable and unfavorable factors on the species reproduction is needed، especially in the case of palatable and nitrogen-fixing legumes with high nutritional value. This study aimed atdetermining the role of pollinators and seed predators and their interaction in seed production of Hedysarum criniferum Boiss. To achieve the goal، the following treatments were applied in the natural habitat of the plant: pollinators excluded/seed predators present; seed predators excluded/pollinators present; seed predators excluded/pollinators excluded; and a control (neither excluded). Tulle-mesh cages were used to prevent insect pollinators and seed predators to affect the plants. The response variables were the number of seeds produced per plant، the number of loments produced per plant and the proportion of attacked fruits by seed predators per plant. The results showed that the pollination impact was supportive and caused a 47. 6 fold increment in loments and a 62. 6 fold increase in produced seeds compared to their absence. It was found that the pollinators were more effective than the seed predators on the reproduction of this plant. In addition، the seed predators infected 27% of the seeds compared to the control. Despite the fact that seed predators caused the loss of about one-fourth of the seeds، the healthy seeds produced by the plant was sufficient such that seed predators were not a significant threat to the plant’s survival. Consequently، seed predators possibly could not be considered as the main factor for patchiness in the distribution of H. criniferum. Moreover، a non-significant herbivory × pollination interaction on seed production of H. criniferum (p≥0. 05) was found.

The aim of this study was to introduce species and sub-species of Coleoptera، Cetoniidae family، as one of the important and useful components of the ecosystem. Activities of insects of this family could be regarded as health indicators in an ecosystem. The present study was performed on the duration of emergence of adult beetles from April to mid and late August in different areas in Gazvin Province، and was repeated from July 2008until September 2013. Sampling was done by direct collecting by hand and trapping methods. Preparation of insects for their preservation in collections and final determination of the specimens was conducted at the Arthropods Museum of the Research Institute of Forests and Rangelands. Overall، a total of 12 species and sub-species of 7 genera were collected. Potosia cuprea mehrabii (Montreuil & Legrand، 2008)، is reported as the only endemic Cetoniidae taxa in Qazvin area.