مجله تحقیقات جنگل های زاگرس
سال دوم شماره 1 (پیاپی 3، بهار و تابسنان 1394)

This study was conducted to investigate the effect of aspect on woody species structure and diversity in the Persian oak (Quercus brantii Lindl.) site, Dashtak area, Kohkiloye and Boyer Ahamd province in western Iran. Measurements were carried out in 3 elevation classes range from 2200 m to 2400 m a.s.l. Then, three sampling plots with area of 2500- m2 were selected in each elevation class. In total, five tree species, including Quercus brantii, Crataegusdavisii, Pistacia atlantica. Subsp. mutica, Lonicera nummulariifolia and Amygdalus communisand three shrub species such as Cerasus microcarpa, Amygdalus orientalis and Daphne mucronata were identified in the study area. In regeneration and tree layers the sum of basal area and average of regeneration's density was higher in southwestern aspect and belonged to Quercus brantii. The results of diversity indices in the tree layer indicated that the average of H’ (Shannon-Wiener index), Evar (Smith-Wilson index) and species richness were higher in southwestern aspect than in the northeastern aspects. In addition, the values of all diversity, evenness and richness indices were significantly higher in southwestern aspect the in shrub and regeneration layers. In general, the results indicated that the diversity indices increased under favorable conditions of ecological, environmental and structural factors. Furthermore, livestock access and exploitation of local people should be restricted off, providing favorable conditions in order to increase the diversity of species.

Rural households’ involvement in forest conservation and reforestation depends on their perception towards forest perceived benefit which is attributed to demographic characteristics of the households head. In order to test this hypothesis, a study was run on rural households surrounded by Chahartagh forest reserve (N=600) which its livelihood was based on forest resources. About 196 rural households were determined as the research sample using Cochran’s formula through Simple random sampling procedure. Also, a researcher-designed questionnaire was used to collect data which its content validity confirmed by expert opinions and its reliability confirmed by Cronbach alpha coefficient. Collected data were analyzed by two software of IBMSPSS21 and LISREL8.5. The results showed that rural households’ perceptions towards forest are directly related to benefits they perceived from the forest. Perceptions towards forest benefits was summarized into three categories of perceptions towards forest economic, environmental and social benefits which economic benefit was recognized as the most important benefit perceived by respondents. From rural households’ perspective, the income gained from timber and non-timber products were the most important economic benefits of forests. Structural equation modeling results also revealed that rural household’ perception towards forest benefits differ among rural households according to their demographic characteristics. It observed that the younger, higher literacy level, had the higher income level and also, they had the more positive perception toward forest benefit. Also, each household’s head that was member of rural local institutions, had a corporation with NGOs and had participation into active groups to conserve forests had more positively perceived forest benefits.

In this study, the impact of land use change of forest areas to forest parks on species diversity indices in Chaghasabz Park (Ilam city) has been investigated. For this purpose, three regions in 30-hectare areas were considered, including the area, without, medium and intensive recreation. The field data were obtained using 20 sample plots with each plot covering an area of 400 m2 in a systematic random design (150 m×100 m) in each region. In order to record the herbaceous species, cover percentage for each herbaceous species was recorded in four micro-plots (1.5 m× 1.5 m) that were defined with Domin criterion. In order to evaluate plant diversity, biodiversity indices e.g. Shannon and Simpson and Maguran richness indices were computed. Also, for studying the comparison between the averages of plant diversity indices, Dunken analysis was used. The results showed that in areas without, average and intensive recreation, there were 29, 45 and 21 species respectively. Therophytes were dominant vegetative forms in all three areas. Asperula odorata, Centaurea irritans Wagentz. Marrabium vulgare L., Phlomis olivieri Benth. and Picnomon acarna (L.) Cass were not observed in intensive recreation region. The least shannon and Simpson diversity and richness indices were observed in intensive recreation region, but on the contrary, evenness index was substantial in intensive recreation. We concluded that intense increase of recreation in forest region might cause a loss species diversity.

To evaluate the quantitative and qualitative characteristics of forest park of Shourab's trees, consisting of Pinus brutia, Pinus pinea, Cupressus arizonica, Cupressus sempervirens var. sempervirens, Cupressus sempervirens var. Horizontals, Ailantus altissima, Robinia pseudoacasia and Fraxinus rotundifolia, inventory as a systematic random sampling and in statistical grid 100×150 meter and in 30 circular sample plots (2R) was undertaken. In each sample plot, tree's quantitative and qualitative characteristics, such as diameter at breast height,basal area of tree, tree height, crown coverage percent, h/d factor, regeneration, vitality, crown form and branchiness on the trunk were examined and measured. According to the results, about 75 percent of the species was due to conifers, especially Pinus brutia (45 percent), and 25 percent of hardwood species formed forest park trees. Also the average number of species in whole park was 604.05 per ha. The results shown that the average diameter at breast height, tree height and basal area of tree softwood species-particularly Pinus brutia and Cupressus arizonica, amounted to 23.02 cm, 9.5 m, 0.048 m2 and 13.47 cm, 8.02 m and 0.042 m2 higher than other species. With the concern of vitality, in softwoods, Cupressus arizonica specie had the most vitality range (85/75) percent and in hardwoods, Robinia pseudoacasia and species had the lowest vitality range (37.27) percent. Finally, we could say Softwood species afforested in terms of qualitative and quantitative indicators of hardwood species, is preferred. Nevertheless, the species of: Pinus brutia and Cupressus arizonica which have exhibited comparatively better performance are suggested for future afforestation expansion in this park.

Persian oak (Quercus brantii Lindl.) has a wide distribution in central Zagros forests and it is the prevalent species in this region. Considering the high volume of demolition and the importance of safekeeping of this jungle, investigation and knowing the structure and the situation of this forest from the qunatitative and qualitative aspects is necessary. This study accomplished to investigate the condition of the Iranian oaks (Quercus brantii Lindl.) forests from the qunatitativeand qualitative aspects of Bazoft district of Kouhrang township of Chahar Mahal and Bakhtiaris province. In this respect, 60 numbers of plots with 400 meter distance in a randomize systematic method established in the area. Then in the studding plots the quantitativecharacteristics of trees like: dbh, trees high, crown diameter measured and some characteristics like canopy percent and firewoods were estimated and registered. Also qunatitative marks from 1 to 4 were given to the trees and they were recorded and data were analyzed. The results shown that the jungle wasa non- coeval and it was sparse forest. Also, 81% of the region had 0-25% coverage. The most density and firewood volume was observedin northeast direction. Also,75% of the trees were inthe proper degrees of Succulence. The results of this study showed the average and a suitable situation of study area stands in comparison to the other regions of central Zagros forests.

Natural regeneration is the most important principle to maintain and sustain of vegetation in each region, therefore, doing the research about the relationship between natural regeneration and environmental factors can be useful for conducting a better management in these regions.Therefore, this study aimed to investigate the effects of physiographic factors and soil parameters on natural regeneration of trees and shrubs species in the forest of Baye Mountain in Eyvan city, Ilam province. Using systematic random sampling, 27 plots were implemented in the area with a total area of 900 square meters. Then environmental factors (physiographic and soil) and the number of natural regeneration were studied and measured. Correlation analysis showed that Cerasus microcarpa regeneration had positive correlation with OM and Ca and negative with EC. Regeneration of Acer monspessulanum L. had negative correlation with clay, and Amygdalus lycioides regeneration had positive correlation with silt, while there was no significant correlation between other species and other soil factors. The results showed that elevation had significant effects on natural regeneration of Cratagus pontica and Amygdalus lycioides, while the slope of gradient hadnt any significant effect on regeneration. Only, aspect had significant effects on Cerasus microcarpa regeneration, and regeneration of this species in the eastern and northwestern direction was more than other aspects.

The main objective of this study was to estimate the effect of decline disturbance on diameter distribution of coppice oak trees in central Zagros region. For this purpose, two similar stands with equal areas (32ha) in central Zagros (Shorab in Lorestan province and Zarabin in Ilam province) were selected. Diameter at the breast height of declined trees was recorded before and after cutting using 100% inventory method. Following probability density functions (PDFs) Beta, Jonson, Weibull, Gamma, Normal and Log-normal were fitted to the data. The results of goodness of fit tests shown that Beta, Weibull and Jonson PDFs were fitted well to diameter of woody stems in Shorab but Jonson, Beta PDFs were much m ore suitable for Zarabin region. The difference of diameter at hight breast was studied in two stages of before and after declining by means of mortality PDF and using different PDFs. There was a big difference in diameter classes between before and after decline disturbance according to mortality distribution. There was no difference between before and after decline disturbance based upon statistical distribution fitting criteria. Outbreak of decline within this region had merely similar influences on all diameter classes, and as a result, it had not a significant effect on overall diameter fit.