مجله جنگل ایران
سال هفتم شماره 3 (پاییز 1394)

The genus of hawthorn(Crataegus L.) is considered as the most important ornamental and medicinal shrubs and is resistant to environmental conditions. Its seed germination is poor, due to stony endocarp and embryo dormancy. In order to evaluate the germination of Crataegus pseudoheterophylla seed under mechanical scarification and hydrogen peroxide treatments, the seeds were sown in plastic pots as randomized completely block design (RCBD) with three replicates. Treatments including mechanical scarification and soaking in 1% hydrogen peroxide for 0, 40, 60, 90, 120, 150, 180, 210 and 240 minutes in combination with alternate layering (one month at 4°C and 2 weeks at 23°C, one month at 4°C and 2 weeks at 23°C, 4 weeks at 4°C) were applied. Carotenoid contents, anthocyanin, soluble carbohydrates, and minerals in fruit and seed were determined. The highest germination percentage was obtained in mechanical scarification (19.7%) for 240 min. and in hydrogen peroxide (26.7%) for 120 min. In fruit and seed, the amount of Carotenoid, anthocyanin, soluble carbohydrates were 0.598 and 0.27 mg/FW, 6.3 and 0.33 mg/g DW, 89.3 and 15.4 g/100 g DW, respectively. Also, the concentrations of Ca, P, K, Mg, and N were 3076.4 and 892 mg/Kg, 2023.9 and 701.8 mg/Kg, 6391.3 and 1456 mg/Kg, 904.6 and 346.4 mg/Kg, 1.2 and 0%, respectively. It is concluded that seeds of hawthorn including deep endocarp and physiological dormancy and fruit and seed of hawthorn are a rich source of phenolic contents, soluble carbohydrates, carotenoids and minerals.

Northern Zagros forests are one of the most important ecosystems in Iran from ecological and socio-economic points of view. This study was done to determine the most important gradients affecting on plant species distribution by using ordination methods. Environmental variables including inclination, slope aspect, elevation, litter depth, bare soil percentage, soil organic carbon, available P, K, N, soil texture, pH and EC were measured in 60 plots along with vegetation data and canopy cover. Redundancy detrended analysis (RDA) was performed to identify the main environmental gradients. 90 plant species belonging to 75 genus and 32 families were determined. Species belonging to Asteraceae, Apiaceae, Poaceae, and Fabacea families had the most contribution in floristic composition. RDA results showed that with considering spatial autocorrelation of sample plots as covariate, slope aspect, litter depth, canopy cover, C/N, elevation and outcrop explained 30% of the total variations in floristic composition. The results of this study can be used to do more efficient management of these fragile ecosystems.

Drought is an important problem in habitat restoration and afforestation of woodlands in arid and hot regions. To overcome this problem and achieve a proper and an easy method to store moisture in the soil, one of hydrophilic polymer called "TerraCottem" was compared with other methods of water conservation. In this research, potential of polymer in water holding and absorption and their effects on survival and growth characteristics of Moringa peregrina were studied. In order to investigate the effect of moisture conservation methods on M. peregrina planting, a trial conducted as split-plot design with three replicates in which main plots consisted of: seed and pot seedling and sub/plots consisted of five conservation methods (straw and dried residual at the bottom of planting dig, tourkinest, plastic film, polymer materials mixed with soil and ditch) at Bashagard region in 2008 for four years. The results showed that absorption and water-holding capacity decreased with time by the polymers, so that after 2200 days reduced to zero. The results indicated that there were significant differences between the moisture conservation methods with respect to Moringa mortality. The highest survival belonged to dried residual and plastic film treatments 24% and 14%, respectively. The lowest survival belonged to polymer material and ditch treatments. There were significant differences between the storage systems in respect to M. peregrina growth characteristics: total height, stem diameter and canopy cover (p<0.01) and dry residual, tourkinest and plastic film treatments had the greatest performance whereas polymer and ditch showed lowest performance. Therefore, with reducing the polymer's ability for absorbing and holding water in long term, application of polymer in rain-fed plantations in hot and dry regions with medium to heavy textured soils and alkaline is not recommended.

Mycorrhizal fungi are essential components of sustainable soil–plant systems and have a main role in sustainable forestry. The present study was carried out to investigate the evaluating status of mycorrhizal symbiosis, activities of acid and alkaline phosphatase and some nutrients (phosphorus, nitrogen and potassium) in rhizosphere of Lonicera nummulariifolia located in Chahartagh Ardal habitat in Chaharmahal va Bakhtiari Province. For this purpose, roots of five trees of L. nummulariifoli and soils around them were sampled in spring and autumn. The results showed that Lonicera is an incredible symbiosis since the percentage of colonization was 90.2 and 80.6 in spring and autumn, respectively. The activity of acid and alkaline phosphatase also was 240.59 and 392.85 in spring and 146.48 and 295 (ρNP) in autumn, respectively. All measured elements had higher values in spring than autumn. Correlation was significant between soil phosphatases with total nitrogen and organic matter in spring and alkaline phosphatase with total nitrogen in autumn. High level of AMF colonization and acid phosphatase activity in spring may be due to good conditions of soil and growing of root hairs are in the early growing season. With regard to the microbial origin of alkaline phosphatase, increasing this enzyme in spring illustrated increasing the quality and quantity of microorganisms and mineralization of organic matter and rising nutrients. In general, impressive percentage of mycorrhizal colonization in L. nummulariifolia indicates dependency of this species to mycorrhizal symbiosis. Therefore, the role of these fungi in planting with this species, especially in destruction habitats, is vital.

In order to test a hypothesis that participatory behavior of villagers towards forest conservation explained by their awareness and attitudes about forest importance, this study was conducted on rural households surrounding Chahartagh Forest Reserve (N=600). According to such criteria as objective, variable control degree and data gathering method, this study was empirical, survey and descriptive research, respectively. The statistical sample size was calculated 196 households through Cochran’s formula. Simple random sampling was done to select the study cases and a researcher-designed questionnaire used to collect data which its content validity confirmed by experts opinions and its reliability confirmed by Cronbach alpha coefficient. The data were analyzed by IBM SPSS ver.21 and LISREL ver. 8.5 softwares. The results showed that households’ livelihood almost depended on forest resources and the majority of them were low-literacy, low income and high sponsorship. Structural modelling results of households’ participatory behavior in forest conservation also revealed that the model explained their behavior properly and was valid. Also, the main hypothesis of the study was confirmed that the households’ participation to forest conservation was a function of their awareness and attitude toward forest importance as these two components could totally explained 60 percent of participation variances. Finally, one unit increase in awareness and attitudes variables increased the amount of households’ participation to conserve forest to 0.32 and 0.41 units, respectively.

Gilan is one of the rich genetic resources ofsweet chestnut (Castanea sativa Mill.). The study on genetic variation of this gene pool is the first step in breeding programs like introducing new promising cultivars. In this study, the genetic diversity and structure of three C. sativa populations including 41 genotypes in Guilan province was studied using SSR markers. Among fourteen analyzed microsatellites, 10 showed polymorphism. In total, 31 polymorphic alleles were detected. The average of observed alleles was equal to 3.10 in each locus. Expected and observed heterozygosity were 0.542 and 0.556, respectively. The Fst and gene flow value were 0.174 and 1.18, respectively, which indicating the high genetic differentiation between populations. The highest genetic distance was found between Shaft and Shafarud populations and lowest genetic distance was found between Fuman and Shafarud populations. The results of this study showed that SSR markers are of high performance in determining the amount of genetic diversity and distinction in populations of European chestnut. Geographic separation and natural barriers and transportation of seeds by human are the important factors in this regard.

Due to increasing demand for recreational activities in forested area, forest parks are being developed rapidly. A well-organized road network is very important infrastructure to access this kind of area. For such area and land use the road network should meet not only the technical criteria but also landscape and vision criteria. This study was conducted to assess the existing road network of Yasouj Forest Park (YFP), from technical and landscape points of view. Various landscapes were selected within YFP area to be assessed using a 200×250 meter sampling network. Technical criteria were then weighted using the pair-wise comparison method. Finally, Multi Criteria Evaluation (MCE) technique was used to assess the existing road network based on both technical and landscape criteria in GIS environment. According to the results, only 25% of the road network is located in the best rated classification. Also, our results showed that some parts of the existing roads were constructed in susceptible areas for erosion causing more cost for road maintenance in future. Results of this research can be a suitable guide to improve the current situation of the road network of YFP.

Heavy soil compaction may impose a serious threat to soil ecosystem functioning.The penetration resistance reduces the elongation and penetration of roots and thus lowers the uptake of water and nutrients. This study used a soil strength (penetration resistance) experiment in a greenhouse to test the hypotheses that increasing soil strength would adversely alter seedling architecture by changing above- and below-ground biomass allocation patterns. The effects of soil compaction were explored in a loam to clay-loam textured soil with optimal conditions of water on a continuous scale (0.1–1.0 MPa penetration resistance) on biomass allocation responses and architecture of the deciduous Quercus castaneifolia (C.A.M.). Results showed that below-ground metrics of fresh and dry biomass (main and lateral root biomass) were negatively affected by soil compaction. Increasing soil strength did not change above- and below-ground biomass allocation patterns (i.e., root mass ratio, root: shoot ratio, specific root length), resulting in unchanged seedling architecture. It is concluded that in loam to clay-loam textured soil with optimal conditions of water and soil strengths of up to 1.0 MPa, increasing soil compaction did not cause significant growth allocation patterns to above- and below-ground portions leading to architectural changes in the seedlings, concluding that plant architecture was found to be less sensitive to increased soil compaction than size/growth and hence not a very reliable predictor of size/growth responses.

Fast germination in Haloxylon persicum is considered as an adaptation strategy to salty and drought areas, so that, if enough moisture is prepared for the seeds in a short period, the seeds can germinate and establish very fast. Germination of plants as an important growing stage, often influenced by environmental stresses, particularly salinity. This study was conducted to evaluate the salt tolerance in Haloxylon persicum, at the germination stage. Salinity levels, including 0, 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 mM (Nacl) were applied as randomized complete design with three replicates in the laboratory. Germination percentage and rate were measured in the Petri dishes, and radicle and stem let lengths were recorded at seedling stage. Although germination rate decreased with increasing salinity, but the results showed that Haloxylon persicum has about 43% seed germination in 350 mM Nacl and was able to withstand the salt content naturally. Results indicated that increasing salinity caused a significant (p<0.01) reduction in percentage germination and rate, radicle lengths, stemlet lengths and vigor index.

Forest management has a decisive role in decreasing or increasing snow damages on trees due to effects on stands structure. In this research snow damages on trees were investigated and compared in managed and natural stands with selection silvicultural system in Nav-Asalem Forests, Guilan province. Circular 0.1 ha sample plots were established using random-systematic method for studying the effects of snow on different species with various ages. The distance between sample plots were set to 100 m. The results showed that the frequency of snow-damaged trees in managed stand (10.2%) was significantly higher (P < 0.01) than natural stand (7.2%). The occurred changes in the age structure and tree species composition in the managed stand during selection cuts was the main cause of most snow damage in this stand compared to natural stand. The most frequency of damages was observed on young trees with high slenderness coefficient. For fortifying the studied forests against risk of snow damage the following recommendations can be mentioned: increasing the selection cutting period from 10 to 20 years, reducing the removed volume in each logging period, reducing the areas of regeneration gaps, increasing the number of large trees, avoiding the cutting trees in forest edges, implementing the thinning operation in the stands in which previous cuttings caused homogenous, even aged, young stands with high slenderness coefficient, and avoiding tree cutting in the areas that are sensitive to snow damage such as ridges, steep slopes with low depth of soil.