مجله تحقیقات جنگل های زاگرس
پیاپی 1 (بهار و تابستان1393)

Undoubtedly، identifying and introducing drought resistant species for reforestation of the Zagros forests should be considered by forest specialists.، the current research identified mechanisms of drought tolerance in Hawthorn (CrataegusaroniaL.) and Mahaleb (Prunusmahaleb L.) seedlings in a greenhouse experiment using a completely randomized design. The experiment contained 3 stress treatments with 5 replications each. The treatments were soil moisture as control (based on field capacity)، moderate stress (based on 50% field capacity) and severe stress (water withholding). Our findings showed that relative water content and stem water potential decreased in both species with increasing of drought severity. Although the total chlorophyll content was no affected by drought stress، carotenoid content was declined in response to the stress. Proline and total soluble carbohydrate concentration، as osmotic adjustments، increased in both species. According to electrolyte leakage and malondialdehyde results، we concluded that Hawthorn can tolerate moderate and gradual drought stress by the means of some adaptations but accidental water withholding stress leads to oxidative stress in this species. On the other hand، although moderate and gradual drought stress leads to oxidative stress on the Mahaleb، but accidental water withholding stress did not have the same course of negative effect as it had on Hawthorn.

Brant oak (Quercusbrantii) is one of the most abundant tree species in Zagros forests but there have been scantefforts to its propagation via shoot cuttings approach. Any achievement in its asexual reproduction shall accelerate the breeding improvements. For this purpose، under growing twigs of Brant oak with and without apical bud were cultured in different culture mediums of half MS and WPM adopting in vitro conditions. In order to study of the explants'' sterilization، four kinds of sterilizing reagent consist of ethanol، mercury chloride، sodium and calcium hypochlorite with and without Tween as a surfactant in different concentrations were tested and the rate of contamination، phenolic leakage and browning of explants were recorded. The effect of different treatments of ascorbic acid، acetic acid، PVP، activated charcoal and darkness on phenolic leakage and browning of explants were evaluated. The ratio of proliferation and callus formation with different NAA and BAP concentrations were investigated. Finally the rooting vigor of explants by four auxin combinations (control، 0. 4 mg L-1 NAA، 0. 4 mg L-1 IBA and a mixture of NAA and IBA with amount of 0. 1 and 0. 3 mg L-1) and three cytokinin concentration (0، 0. 4 and 1 mg L-1) were assessed. The results revealed that the best suitable condition to establish and proliferate of under growing twigs of Brant oak was sterilizing the explants using mercuric chloride 0. 1% (w/v) and transferring to WPM medium containing 0. 5 mg L-1 PVP or activated charcoal. Increasing BAP and NAA concentrations up to 1 and 0. 1 mg L-1 respectively had no significant effect on proliferation rate of explants. None of the rooting treatments were conducted to root formation in explants.

Crown dieback is of the phenomena that mainly has affected Persian oak trees. In order to assess the crown dieback of trees in forest stands of oak trees and its relationship with the individual trees، tree origin and size of tree canopy، Shalam forested area in the northern half of the Ilam province was selected. After dividing the study area into topographic homogeneous units، the biggest unit was selected for assessing the research objectives. Within the selected unit، 6 parallel transects were laid and about relatively 60 healthy and dieback trees were recorded. Then crown dieback، position of tree in stand، origination of trees، minimum and maximum crown diameter and crown height were measured. Data analysis was performed by analysis of variance and linear regression. Results showed that individual trees had healthier crown than the rest of the trees. Standard trees showed less crown dieback than the coppice trees. Effect of crown size on crown dieback depended on the location of trees as single or group and tree form. Totally it can be concluded that oak trees would give different responses to drought in terms of their individual or social characteristics and also it was seen a range of crown dieback with different intensity/pattern within stand in individual to group trees.

In forest ecosystems espcially riparian ones، individual trees have important effects on soil macrofauna. This research was conducted to study the effect of Populuseuphratica on soil macrofauna in Karoon River Side Forest near Shooshtar. Soil macrofauna were sampled in November 2012. Soil macrofauna under tree crown (in three crown diameter category) on parallel transects with 100 m distance from the river and eachother was sampled. Soil macrofauna in 50 cm× 50 cm plots upto 10 cm depth were hand sorted and identified to family level. Totally 342 plots were sampled. The results of correlation showed that there were negetive relationship between distance to tree crown center and soil macrofauna and this relationship was higher in the case of trees with lager crown. The results of ANOVA also showed that the crown diameter size did not have significant effect on soil macrofauna except on soil macrofauna evenness with low significant level. The correlation of distance to river with soil macrofauna showed higher abondance، richness and diversity in farther distances to the river while evenness were higher near the river. Totally it should be saied that indvidual P. euphratica wereeffective on soil macrofauna and it also should be considered the distance from riverside had massive influence on crown diamere.

Protection and developing of biodiversity are the most important subjects in forest management. The aim of this study was classification of ecological groups in Vezg forest of Yasouj and evaluation of biodiversity indicators in ecological groups. For this purpose، 52 sample plots 450 m2 were measured with systematically random method for collecting of vegetation. The TWINSPAN method and Canonical Correspondence Analysis (CCA) were used for the definition of ecological species groups and determining the relationship between ecological species groups and biodiversity indices. Also، plant biodiversity were studied based on species abundance data with general biodiversity indices. Also Tukey test and Pearson correlation analysis were used for finding significant differences between the ecological groups، alsodiscriminate analysis was used for determining of significant biodiversity indices and separate of ecological groups. Results showed that، there were four ecological species groups in the study area. The First group including: Anchusa italic-Quercusbrantii، the second group: Heterantheliumpiliferum-Avenaclauda، the third group: Teucriumpolium and the fourth group: Salvia reautreana. The ecological groups were significantly different in terms of all diversity، richness and evenness indices، so that were greater in the third and fourth ecological groups that were in high elevation and north slopes. The second and third ecological groups showedthe highest and lowest beta diversity respectively. Therophytes had the highest life forms spectrum in all of ecological groups and in geographical distribution، the forth group had the highest Irano-Turanian and Cosmopolite species. Results showed that، Shanonweaner diversity and Menhenik richness indicators، were the most important effective factors in separations of ecological groups.

Despite the implementation of watershed management projects over a wide area has long history in Iran، but the quantitative assessment of these projects have been neglected. In this study، the effects of watershed management project of Kalan-e-Eyvan in Ilam province from ecological point of view (the relation of vegetation composition with physicochemical soil properties) were investigated. In doing so، four status of watersheds were assessed، namely، status A (implemented area after 5 years in 2010)، status B (the witness area without implementation of plan in 2005)، status C (the witness area without implementation of plan in 2010) and status D (the area A before implementation of the project in 2005). The results showed that plant species in four statuses were classified into two groups based upon Canonical Correspondence Analysis (CCA) and the species in A، B and C statuses were mostly perennial classified as climax stage species. The results showed a floristic similarity between planed and control areas after 5 yearsturned out. There werea clear differences regarding to vegetation composition، nutrient and saturation percentage (SP) between the area after and before plan implementation. The results of one-way ANOVA indicated significant differences regarding to diversity and richness between four statuses. The results of Duncan-Test showed that the implementation of watershed management project has caused increasing in diversity and richness in planned areas in comparison with non-planned watershed management ones.

Paulownia species، which are fast-growing endemic species in China and Japan، have been used for establishing green space and park and inter-cropping with many kinds of crops in many countries. The aim of this study was to investigate the effect of irrigation on one-year Paulownia tomentosa seedlings in the climatic and edaphic condition of West Azarbayjan، Iran. Random factorial experimental design was applied with 3 irrigation levels (5، 10 and 15 liter) and 2 irrigation period treatments (3 and 6 days) with 10 replicates. Seedling’s height increment was measured at the end of each month during the growth season. The maximum height growth of Paulownia tomentosa in different treatments was observed in the first month and the seedling height was not considerably raised during the upcoming months. The seedlings of the treatment which were irrigated with 5 liters and with 6 days interval were dried and the seedlings of the treatment with 5 liters irrigation and with 3 days interval had the minimum mean of total height (8. 7cm) in comparing with other treatments (10. 9-11. 8cm). Furthermore، with increasing the irrigation amount and decreasing the irrigation interval، the seedling’s height growth was not altered significantly. Therefore we concluded that the best irrigation regime for suitable height growth of one-year Paulownia tomentosawas with 10 liters irrigation and with 6 days interval، for decreasing the cost and water consumption.