مجله جنگل ایران
سال نهم شماره 4 (زمستان 1396)

This study aimed to investigate effect of forest roads on amount of soil elements: nitrogen, phosphorus, potassium and pH in the Caspian Forest of Iran. For this purpose, main and secondary forest roads were chosen in second district in Kheyroud forest. 16 transects (8 transects in the main roads and 8 transects in the secondary roads) was established with 100 meters length from roadside into the forest interior. Four plots established at 0, 5, 60 and 100 m distances. The amount of nitrogen, according to the Tukey test, in the main roads and cut slope, was significant in the 60 and 100 m distances and their values were more than 0 distance. However in the edge of secondary roads, there was a significant difference, in both cut and fill slope and its value is less than other distances. Phosphorus only in roadside and on the down slope of the main road was significantly more than 100 m and there was no significant difference for potassium at different distances of the main and the secondary roads, cut and down slopes. pH, in 0 m distance had a significant difference and its value was more than other distances in the main and the secondary roads. The results showed that changes due to soil disturbance caused by road construction affect chemical elements of soil and pH, so that is necessary to reduce degree of destruction and disturbance in road construction as much as possible, with respect to technical principle and following the nature.

Atmospheric heavy metals pollutions affect needles anatomical properties of coniferous trees. The present study investigated the accumulation of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), and chromium (Cr) on needles of Pinus eldarica and leaves anatomical responses to urban pollutions in downtown of Tehran Mega city (Keshavarz Boulevard, henceforth KB) as the highest polluted area and in the Chitgar Forest Park (hereafter CFP), west of Tehran, as the lowest. To achieve this, needles were collected in 2015, summer season and structural characteristics needles, i.e., leaf surface, stomatal density, width and length of stomata, as well as epidermis and cuticle thickness, were measured. The results exhibited that the concentrations of Cd, Pb, Cr, and Cu in KB were 0.51, 8.41, 0.51 and 4.2 µg/g, respectively, which were more than those in the CFP (0.05, 2.18, 0.1 and 3.8 µg/g, respectively). No significant difference, however, was detected between KB and CFP in terms of Zn and Ni concentrations. Leaf area in KB (0.132 cm2) was less than that in CFP (0.137 cm2). Stomatal density and length in KB were 92 per mm2 and 20.9 µm, respectively, against those of CFP (112 per mm2 and 24.13 µm). Upper and lower epidermises in KB (5.3, 5.4 µm, respectively) was significantly thinner than those in CFP (6.2, 6.1 µm). The observed changes in anatomical properties are physiological and structural strategies of P. eldarica leaves against stress tolerance induced by urban pollutions. P. eldarica is anatomically sensitive to the pollutants concentrations measured in this study and needle leaves structural characteristics change to adapt to the pollution stress.

Nowadays, increasing consumption of oil and other fossil fuels in Iran, as well as growing development in the extraction, exploitation, and refining of these fossil resources, has increased the sensitivity of the environment and human societies. In this research, the germination performance of black locust, Judas tree, ash, Chinaberry and tree of heaven seeds was studied in a completely randomized block design with three replicates (each replicate with three pots). Seed germination counting began with the average time of elevated emergence on the soil in the pots. This counting was continued until the end of germination and the initial growing characteristics were measured. The result indicated that most of the measured germination indicators of studied saplings were decreased with increasing contamination levels. Soil treatment with 400 g/kg of oil sludge as the highest contamination level not only did not decrease the speed and average germination time in asparagus seed, but also the average percentage of germination (21%) and seed vigor index (33.91% percent) were decreased less than other species. Growth response results of the studied species showed that the growth performance of ash species was not decreased compared to other species in the conditions of oil sludge contamination, while in some of the studied species, decreased growth up to 76% was observed and recorded under the intense contamination.

Traditional forest management in Zagros forests is rooted in traditional ecological knowledge for livelihood needs. In this study, three prevalent models of silvopastoral management including young coppices (YC), old-age coppices (OC) and transitional structure (TS) as well as a preserved stand (PS) were compared. Trees were measured in the variable-area sample plots and stand structure of each management model was evaluated using structural diversity indices including Margalef, Berger-Parker, Shannon diversity, Simpson, and Shannon evenness. Results showed that average diameter and height of trees in OC and PS were significantly greater than both younger stands. The YC was characterized by maximum stand density, lowest basal area, an acceptable rate of regeneration, and negative exponential diameter distribution with a considerably limited size span. Positively skewed bell-shaped diameter distribution was observed in OC and TS which conversely to the YC have significantly wider size span and lower regeneration rates. Based on the indices, the maximum and minimum size diversity were observed in PS and TS, respectively while OC had the most diverse structure among the harvested stands. Due to weaknesses like limited diameter range, abundance of young individuals and low stocking level, YC structural diversity was lower than OC. Despite the lack of adequate regeneration and young stems, structural diversity of OC model was interesting. Finally, stocking in the YC stands as well as improvement of regeneration in the OC stands were suggested in order to regulate the forest structure.

In recent years, a large area of ​​Ilam forests has been affected by oak decline. The purpose of this study was to investigate the oak decline for two inventory periods in Sarab-Kazan forests, west of Sarableh city, Ilam province. The first inventory was done in 2012. Systematic-random sampling with 200×150 meter grid was done in 0.1 ha rectangular sample plots measuring 40 × 25 m (1000 m2) and 80 sample plots were established in 120 hectares. In each sample plot, tree species, DBH, tree health were measured. For this purpose, declining trees were classified into 1: very high (more than 75%), 2: high (50%-75%), 3: medium (25%-50%), 4: low (less than 25%), and 5: healthy. In 2014, the second inventory was carried out in the same sample plots. Mann-Whitney test was used to compare the tree decline in two inventories. The results indicated that tree decline in the very high declining class raised from 3.5% (2012) to 11.2% (2014). There was a significant difference between the first and second inventories according to Mann-Whitney test (P≤0.05). Moreover, the highest decline was observed in class 10 and 15 cm. In contrast, the lowest decline was recorded in 40 and 50 cm. Our findings showed that DBH has a relationship with oak decline. Hence, in order to manage the forest stands with oak decline in Ilam province, it is recommended trees with 7-20 cm DBH were further considered.

Any restoration and improvement programs for Persian oak stands require assessment of the structure of genetic variation within and among the natural populations and realize the genetic distance patterns. Vulnerability against biotic and abiotic stresses is the consequence of the reduction in genetic diversity. Genetic variation is crucial for natural populations of organisms to evolve in response to changing environmental variables. Low level of diversity in the gene pool of plant spices may lead to increased risk of extinction in the face to abiotic and biotic environmental stresses. Genetic diversity of 180 Persian oak trees from central Zagros region including Kermanshah, Ilam and Lorestan provinces was investigated. Fifteen ISSR loci amplified and 157 alleles produced which 99.17 percent (156 alleles) were polymorph. Allele number per locus was in a range from 4 (UBC814) to 17 (ISSR16) with average 10.47; polymorphism information content was different from 0.052 (UBC895) to 0.425 (UBC807). Amplified fragments were in a range from 150bp to 1800bp. AMOVA shows 20 percent of variation among and 80 percent of variation within populations. The minimum genetic distance was manifested in Lorestan populations and the maximum distance was in Kermanshah. Results showed the higher levels of differentiation among Kermanshah and Lorestan genotypes. Heterogeny of evaluated loci in populations in Kermanshah was more than others in Lorestan and Ilam. Cluster analysis led to groping of genotypes in five distinct clusters. Amplification and suitable polymorphism of ISSR markers in Persian oak and also a high level of molecular variance between populations are promising for the capacity of this molecular marker system to detect the informative alleles for phenotypic traits.

Variations in leaf phenology, precipitation characteristics, and meteorological conditions may cause the seasonal change in the quantity and quality of precipitation components (including stemflow, SF; throughfall, TF; and interception loss, I) of deciduous stands. This study was conducted in an Oriental beech stand located at Shast-Kalate forest, with semi-humid climate. In order to measure I, a total of 31 trees were randomly selected. Field measurements of gross precipitation (PG), SF, and TF were made over a period of one year from November 2005 to November 2006. Total PG was 827.1 mm. Mean proportion of I (I:PG) were obtained during spring (52.4%), summer (66.1%), autumn (58.2%), winter (53.5%), and the leafed (56.5%) and leafless (56.7%) periods. ANOVA revealed an significant difference of SF:PG, TF:PG, and, I:PG (p

Taxus baccata L. is one of the native and valuable species of Hyrcanian forest which is used in large scale in landscaping. In order to investigate the type of tissue cuttings (softwood, semi-hardwood and hardwood) and indole butyric acid hormones (four levels 5000, 2500, 500.0 mg L-1) in combination with rooting-cofactors (hydrogen peroxide 3% and putrescine 1 MM), a factorial experiment was conducted in a completely randomized design with four replicates. After five months from the time of cuttings, rooting percentage, root number, length of the largest root, leaf number, total chlorophyll, total phenol and number of callus cuttings were investigated. According to the results, the effect of tissue type, hormonal treatments and their interaction on the studied traits was significant. Treatment with Indole Buteric Acid (IBA) at a concentration of 5000 mg L-1 hydrogen peroxide 3% was the best treatment in increasing the rooting rate, number of roots, root length and leaflet production in semi-hardwood cuttings. The total phenol content in the hardened cuttings was less than that of soft cuttings. In the control (distilled water) treatment, cuttings produced calluses, but rooting did not take place. Among the rooting promoter materials, hydrogen peroxide was better than putrescine. The highest percentage of rooting and number of roots were related to semi-hardwood cuttings. Therefore, according to the results, the use of indole butyric acid in high concentrations and the use of hydrogen peroxide to facilitate the rooting of semi-hardwood cuttings of yew are recommended because of superiority to the control.

Utilizing public participation in protecting and restoring the natural resources is considered as a milestone. So the emphasis on public participation in decision-making of natural resources conservation is the solution. The aim of this research was to determine the affecting factors on local communities’ participation in the rehabilitation of degraded forestlands project in Rigan County, Kerman Province. Using descriptive research and survey technique, 360 of the participants in the project were randomly selected. Data were collected through a questionnaire which its validity and reliability were confirmed by a pilot study. The correlation test showed that there is a significant and positive relationship between variables of education level, farm, and garden size and social norms, and a negative relationship between social capital, cultural capital and participation of local communities in the project. The regression analysis showed that 38 percent of participation variability was explained by the variables such as cultural capital, social capital, farm size, number of sheep and amount of monthly income. This study recommended more communication with the local community by experts and more attention to the participation of certain groups such as women in the project.

Forest resources mapping is a prerequisite for sustainable forest management. Site productivity is a key indicator of forest ecosystem services like wood production, carbon sequestration, etc. Due to the extent of Hyrcanian forests and mountainous areas in these forests that are sometimes difficult to access, it seems necessary to find suitable methods for mapping the quantitative parameters in these forests. In this study, site form index which is the most reliable criterion for evaluating site productivity of mixed and uneven stands was used. This study aims at mapping beech forest site productivity by using regression kriging in research forest of Tarbiat Modares University. For this purpose, 123 0.1 ha circular sample plots were laid out in beech dominated stands. The height and diameter of beech trees with DBH ≥ 7.5 cm within each plot was recorded. Some primary and secondary variables were also extracted from DEM in sample plots to be used in regression kriging. We investigated the differences between two predictive approaches: random forests and linear regression as the base model for regression kriging technique. Results of 10-fold cross-validation demonstrate that by using criteria such as mean error, mean absolute error, root mean square error, relative mean error, relative root mean square error, the random forests algorithm outperforms the linear regression and kriging techniques, with average decreases of ca. 70% in Root Mean Squared Error (RMSE). Hence, the regression kriging technique with random forest as the base model is recommended in order to better understand the more complex environment-beech forest site productivity relationships.