نشریه بوم شناسی جنگل های ایران
پیاپی 10 (پاییز و زمستان 1396)

Vegetation due to its root system by creating cohesion of soil particles, significantly affects hill slope mechanical properties related to shallow landslides and slope stability. In this regard, the root engineering characteristics of forest species are important. The aim of this study was to investigate the distribution pattern of persian oak and hawthorn in Zagross forests. For this purpose, five trees from both species were randomly selected to study their root distribution. Sampling was performed by using a soil core sampling ring from three horizontal distances and three depths. Root distribution was assessed using the concept of the root area ratio. The results showed that the root area ratio as well as the longitudinal densities of the roots decreases with increasing depth of the soil and increasing the distance from the tree. The maximum root length density was observed in the initial layers and close to the trees. The highest volume density of roots was observed at depths of 0-15 cm. Based on the results of the study, it was found that there was a significant difference between the volume density of root of two persian oak and hawthorn species. Longitudinal and volumetric densities of root in persian oak were higher than hawthorn. In general, the results of this study showed the importance of persian oak in comparison with hawthorn in the field of increasing strength of soil.

TThe forest plantation strategy is to do with the identification of the most appropriate zones and the areas that are most suitable for different species. However, the success of this strategy requires the precise determination of the species ecological demands and the evaluation of the land before the establishment of the plantation. The purpose of this study is to assess the ecological capability and estimate the aboveground biomass for the forest plantation in Darabkola forest, so, the species could be prioritized according to these objectives, and also for future forest plantation in the same. In this study, at first, the suitable zones for the forest plantation was identified using the SQL search function in Arc GIS 10.3 software interface. Then, the carbon sequestration in forest plantation (per hectare) was estimated using the measured parameters of trees and alometric equations. Results showed that, by simultaneously considering the mentioned objectives, Maple, Coliseum maple and Ash, were ranked as the most compatible species from the ecological compatibility point of view, and the highest level of the carbon stock was found for oak species. Therefore, these species are in priority for forest plantation in the region. Due to the fact that, the former forest plantation focused mainly on considering the ecological potential of a given species, the current study emphasized taking into account the multiple objectives for the future forest plantation. In other words, in addition to the ecological capability, other goals should be considered.

Forest roads can create small- scale climate change. These changes can vary with the road age and topographic conditions. This study aimed to identify ecological species group as well as study the relationship between vegetation and environmental factors based on the road age. The study was carried out in three-districts of Nav- Asalem in Watershed 7 of forests of North of Iran. Therefore, 140 sample plats (rectangular in shape and150 m2 in area) with different ages and different topographic conditions were taken. Information related to tree and shrub cover, regeneration and weed cover along with slope (%) and slope aspect of sample plots, road age and elevation, as well as the amount of light receiving to forest floor, temperature and humidity at the center of the sample plots were recorded. The ecological group distribution pattern was evaluated using non-limited ordination method and classification of ecological groups was performed using Two Way Indicator Species Analysis (TWINSPAN) and CCA gradient analysis. Data analysis was carried out using Excel and PC-ORD software. The results of the analysis of indicator species showed that of 72 plant species, only 52 species were determined as indicator species that were defined as indicator species of beech communities on roadside. In this research, newly constructed roads (with age below 10 years) occurred in second and fourth ecological species groups, roads with moderate ages (10-20 years in age) in the third ecological group and older roads (with age more than 20 years) in the first ecological species group. The results of MRPP analysis (multi-response permutation procedure) showed that the ecological groups are characterized by higher distance from each other. Among the ecological groups, the abundance and presence or absence of species with environmental variables were not the same in all sample plots. The final results showed that the road age not only affects the ecological species group but it also serves as a useful factor in determining the indicator species and improving the results of the ordination of the ecological species group on the roads with age more than several years.

Arasbaran region is located in the north west of Iran and north of the east Azarbayjan province and most of these forests are seen in four areas of Kalibarchay, Ilgenechay,Hajilerchay and Selenchay. Result showed that 107 species belonge to 74 genera and 36 families of vascular plants are found. which Dicotyledons with 32 families were the richest group. In terms of abundance, Monocotyledons with 4 families and Gymnospermes with 2 families were in the second and third place respectively and one family with one genus and one specie was also from vascular cryptogam. Families of fabaceae with 18 species, Asteraceae with 13 species. Rosaceae with 8 species, Lamiaceae with 6 species and Poaceae with 6 species were as the most important plant families in term of plant species that included a total of 47.63 % of the total species. Life forms of region plants contains of Hemicryptophytes with 42 species Phanerophytes with 26 species, Therophytes with 25 species, Cryptophytes with 11 species and Chamephytes with 3 species ,which among them Rosaceae had the greatest number of Phanerophytes, peas greatest number of Therophytes, chicory greatest number of Hemicryptophytes, mint largest number of Chamephytes and grasses has the highest number of Cryptophytes. According to classifications were made on the basis of Rannkier system and calculation were made Hemicryptophytes with having 39.25 percent share of the total number of species constitute the dominant life forms of the region which respectively after them Phanerophytes with 24.29% and and Therophytes with 23.36% and Cryptophytes with 10.28% and Chamephytes with 2.80% are in the next orders results of determination of corotype plants of region showed that plants with the Geographical distribution of the Irano-Turanian with 34.5%, Euro- Siberian with 30.5% are the most important group of the Region

Crataegus pontica, Cerasus microcarpa and Amigdalus orientalis are from important accompanying woody plant species in Zagros forests and their regeneration dynamic helps to improve the regeneration of tree species. This research was carried out with the aim of investigating and recognizing the regeneration establishment pattern of C. pontica, C. microcarpa and A. orientalis in three forest sites in Dalab , Ilam province with different site conditions and also studing the their seasonal changes during spring and summer 2016. In each site one basic transect was established perpendicular to the slope and regeneration establishment positions including "under tree canopy", "under shrubs", "under bushes", "next to rocks" and "without vegetation space" with three replications were selected. For each replicate a 15m2 circular permanent plot to investigate the seasonal changes was established and the number and height of seedlings for each species was measured. The results showed that the seasonal changes of C. microcarpa regeneration are associated with a significant decrease. The most density of C. microcarpa seedlings was in south aspect and altitude class of below 1500 m a.s.l., and for A. orientalis was in north aspect and altitude class of above 1500 m a s l. The most density of C. microcarpa seedlings was found under the crown of oak trees, and for C. pontica was under the crown of shrubs and for A. orientalisat was next to the rocks. The most density of seedlings for C. microcarpa, C.pontica and A. orientalis was found in north side of tree crowns and also at the first third of tree crown radius. The most percentage of tall seedlings for C. microcarpa was at a first third of tree crown radius and for C. pontica and A. orientalis was at the third of tree crown radius. It was concluded that the crown of trees and shrubs has the most important role in seedlings establishment and protecting them against cold and heat. However, the role of rocks in soil preserving and seedlings establishment is considerable.

Oak decline as one of the most important environmental problems of Zagros forests, requires proper management to decrease trees dieback and mitigate its effects. This study aimed to find the best sampling method for estimating density and crown canopy of declined oak trees in Zagros Forests. All declined trees in an area of 100 ha of Dinarkooh protected forest were surveyed and trees density, geographical coordinates and their canopy covers were measured and recorded. Then digital map of all trees were made and in order to assess alternative sampling methods with a constant sampling intesity 3% three alternative adaptive cluster, systematic random and random sampling were mapped using 30 sampling 10 Ar plots and the above mentioned data on trees were measured on the map.Results of accuracy criterion, showed superiority of adaptive cluster sampling method to the other methods, for estimating the density and canopy cover of declined trees (5 and 4.76% error of estimate for density and crown canopy respectively). Since adaptive cluster sampling method is designed for sampling of the populations with clump distribution it can be concluded that declined oak trees follow cluster distribution and this sampling method can be recommended as a proper method for estimating declined oak trees in Zagros forest.

Species diversity protection will ensure the protection of natural processes and ecological values. Appropriate information on the condition and location of endanger species will facilitate the management and conservation of forest areas. The present study was conducted in Arasbaran forests for the purpose of evaluating two sampling methods including circular sampling (1000 m2 area) and the nearest neighbor method. Richness, Evenness, Shannon-Wiener and Simpson diversity indices were calculated in BiodiversityR package in the R software environment and the comparison of the means was performed with independent t-test. Results showed that there was no significant difference between the sampling methods and the 100% inventory method in terms of richness, evenness and diversity indices (p≤ 0.05). All diversity indices showed high values of species diversity in the study area. Species importance value (SIV) for tree species showed the high values of this index, so that Acer campestre as the main species in the region. According to the results of this research, the nearest neighbor distance sampling method can be used as an efficient sampling method for estimation of biodiversity in the studied forest ecosystem.