Iranian Journal of Forest and Poplar Research
Year:2019 | Volume:27 | Issue:1 (75)|Papers Count:10

This study aimed at evaluating the box tree (Buxus hyrcana Pojark) habitat after the occurrence of box blight disease in Buxo-Fagtum orientalis (B) and reference pure Fagetum (S) stands in the district 3, Lesakoty catchment No. 36, southeast of Tonekabon in the Mazandaran Province. In each stand, 60 micro-plots with 25 m2 were established, in which the frequency of herbaceous species was recorded. For sampling lichens, 60 × 40 cm quadrats were used. Raw data obtained from the field were compared and analyzed using an independent t-test and CCA analysis. Results revealed that the Simpson species diversity (B = 0. 813 ± 0. 07, S = 0. 649 ± 0. 07) and Shannon-Wiener (B = 0. 830 ± 0. 05, S =0. 577 ± 0. 05) of herbaceous species were significantly higher in Buxo-Fagetum orientalis stand (p < 0. 05). In addition, the independent t-test for lichen species showed that Simpson species diversity (B = 0. 477 ± 0 0. 03, S = 0. 629 ± 0. 03) and Shannon-Weiner (B = 0. 738 ± 0. 06, S= 1. 067± 0/06) in boxwood-beech stand was significantly lower than those in pure beech site (p < 0. 05). CCA results showed that the environmental conditions, as well as the variability of the presence and diversity of different species of lichens as forest ecosystem bio-indicators were changed, mainly due to the boxwood blight disease in boxwood-beech stand. Further, stand opening caused by disturbances and increase of light reaching the forest floor was identified as a key factor in changing the composition of herbaceous and lichen communities in Buxo-Fagetum orientalis stands.

The viability, height, and vitality of Persian oak (Quercus brantii) seedlings from five different seeding techniques were studied in a completely randomized design. The treatments included 1) seeding in holes with 50 cm depth and 40 cm diameter in the shelter of 50% UV resistant laces (shade treatment), 2) seeding in holes with 50 cm depth and 40 cm diameter and pouring down hummus and litters on sown seeds (litter treatment), 3) seeding in holes with 50 cm depth and 40 cm diameter and use of super-absorbent (super absorbent treatment), 4) seeding in holes with depth of 100 cm and a diameter of 60 cm (deep hole treatment), and finally 5) seeding at a depth of 5 cm from the soil surface (control treatment). Also, the relative light intensity in all holes was measured using a fisheye camera, and a regression model was obtained from the seeding survival rate. The results of the comparison of the mean (p <0. 01) indicated that the deep hole, super absorbent, shelter, and litter treatments showed a 134. 5, 138. 2, 178. 6, and 243. 3% increase in seedling viability, respectively. Furthermore, shelter and deep holes treatments revealed a 19. 5% and 31% increase in seedling height, while litter and deep holes treatments had 18% and 31% increase of seeding vitality, respectively. The fitted regression model indicated a significant correlation (R2 = 0. 73, p <0. 01) between viability and relative light percentage (except for the deep hole treatment). Results revealed that litter treatment can be recommended as the most suitable method for the oak seedling. However, further research is required in case of the shade and deep holes treatment, which showed the best survival performance prior to soil erosion and seedings mortality.

Motivated by the general necessity of reforestation in the Zagros forest using native species under limited water resources, this study was conducted on the production of mycorrhizal inoculated-seedlings of Caucasian hackberry (Celtis Caucasica L). Seed samples and rhizosphere were selected from a site in the Chahartagh Ardal of the Chaharmahal and Bakhtiari Province. Two species of mycorrhizal fungi, namely Funneliformis geosporum and Claroideoglomus etunicatum, showed high frequencies in the rhizosphere of C. Caucasica sites. Following isolation by wet sieve method, identification was done according to morphological properties such as spore size and color, spore-attached ridge, and spore cell wall layers, which led to their first-ever description from rhizospheres of C. caucasica in Iran. Next step was to use trap culture method for culturing spores of mycorrhizal fungus in the greenhouse. After propagation of the species, they were inoculated with C. Caucasica seeds. Growth characteristics and root colonization of the seedlings were then assessed during a period of 6 months. The results demonstrated a significant and positive effect of the mycorrhizal fungi on all traits. For most of the measured traits, the highest value was observed in the combined fungus treatment. Therefore, mychorrhizal seedlings were concluded to be advantageous compared with control seedlings. In addition, the use of mychorrhizal seedlings is concluded as a suitable and cost-effective solution to increase the success rates of afforestation as well as the restoration of degraded areas.

The beech (Fagus orientalis Lipsky) stands in the Hyrcanian region of Iran occur on a wide range of soils in a relief row with valley and ridge structures called Catena. This affects soil features and plant species distribution due to its topographic shape and different slope positions. The aim of this study was to compare changes in soil characteristics across V-shaped Catena in the two harvested and non-harvested beech stands in the Asalem region, Guilan Province. We selected three Catena landforms in each non-harvested and harvested stand. In each stand, a 400-m2 plot along each Catena and slope position was designed, in which soil samples were taken from the center and four corners as well as from 10-0 cm, 20-10 cm and 30-20 cm depths. The samples were mixed to obtain a single soil sample for each depth and slope position. Soil samples were transferred to the laboratory to study physical and chemical properties. Based on our results, the variability of soil features was significantly influenced by different depths and forest management plans, whereas they were poorly affected by the different positions of the Catena. The highest amounts of pH and Ec were measured in the harvested stand, while the highest phosphorus and potassium contents were measured in the non-harvested stand and toe slope position, respectively. Absorbable potassium was the only parameter that had a significant difference in management, slope position, and depth of soil interactions. Generally, foot and toe slope positions contained more nutritious soils, which can be attributed to the leaching and erosion of soil from higher to lower slopes.

By considering environmental education as the basic source of knowledge to increase awareness of climate change and environmental issues in students, this was studied here by surveying students residing in Kalibar in the Arasbaran region (as forest dwellers) and Tabriz (as the non-forest dwellers). The main aim of this research was to quantify the students' information on environment and climate change and the effect of workshops in increasing their information. The statistical population consists of 69000 individuals, and data were collected from 221 intermediate-level students by questionnaires distributed in six schools. One school was randomly selected from each of the urban and rural areas of Kalibar, as well as from urban areas of Tabriz, resulting in 6 schools in total. The content validity of the questionnaire was confirmed through a panel of academic and executive specialists. The reliability was also measured using the Cronbach's alpha coefficient in environmental (0. 74) and climate (0. 84) fields. Based on the results, > 90% of students in both forest and non-forest areas emphasized the importance of the Arasbaran forests. Internet was mentioned as the most important source of environmental and climate information among the non-forest (42. 1%) and forest (34. 5%) students. The workshop held for both groups of individuals led to a relative increase of 10% in awareness of climate change. In addition, 34 and 15% of the students in non-forest and forest regions stated that they had previously no information on the climate change consequences, which was increased to 5 and 8% in the post-workshop period, respectively. After the workshop, 63. 5 and 60. 7% of the students in non-forest and forest regions believed that they could and should participate in climate change campaigns. Overall, the results of the research showed that the workshops had a significant effect on increasing the awareness as well as environmental information.

Dwarf mistletoe (Arceuthobium oxycedri (DC. ) M. Bieb. ) has as a worldwide range of distribution amongst the dwarf mistletoe species. To investigate the effects caused by dwarf mistletoe infection on Greek juniper )Juniperus excelsa M. Bieb. ) trees, this study was conducted in an area of 400 hectares in the Parvar protected area, Semnan Province. Sampling was carried out using 60 quadratic plots with the area of 20×20 m2 in a randomly-systematic manner. The discriminant analysis showed that the characteristics of herb canopy cover, individual gender, slope (%), and even aspect direction are not substantially deterministic for infection intensity of dwarf mistletoe. In contrast, the highest correlation was observed in traits like root exposure, collar diameter, crown area, altitude, and tree height. The lowest frequency of infected individuals and the lowest severity of infection were observed in upper elevation class (2500-2700 m a. s. l. ), low rate of soil erosion, and trees without root exposure. Moreover, the proportion of infected individuals to total trees are little on the 30-60% slopes and in north and west slope aspects. The results suggest that trees with broader canopy, higher collar diameter, and taller height are more prone to this parasite. In addition, the maximum severity of the infection is observed on larger trees, especially if the trees are located at lower elevations, faced with the degraded ecosystem and soil erosion that leads to root exposure and tree weakness. Therefore, in the case of the continuation of the spread of dwarf mistletoe in juniper forests and the lack of a non-destructive strategy to control the population of this parasitic herb, these communities would be expected to be partly degraded in the near future especially, for the higher sensitivity areas (such as lower habitats of juniper communities.

This study explored the effect of tree shadings on a number of destruction indices for forest road pavement. Therefore, selective sampling was conducted within three various elevation classes in the Chafroud watershed in the west of the Guilan Province. Pavement distress indices of improper cross section, inadequate roadside drainage, corrugations, potholes and ruts dimensions, and loose aggregate were measured. By surveying the road, the plots with a canopy cover > 50 % and a paired plot beside each plot on the road were selected for measurements. Based on mentioned indexes, 12 distress variables were measured and compared among plots under the shadow of the trees and opened plots in three classes of traffic level. Results of analyses in low elevations showed that distresses of an improper cross section, number and area of potholes of plots with canopy cover > 50% were significantly more than plots with canopy cover < 50 % (p < 0. 05). In middle elevations, no differences were observed between the plots, while in high elevation (i. e. with low traffic) the distresses of improper cross-section, area of ruts, and loosing aggregate plots with canopy cover > 50% were significantly higher than plots with canopy cover < 50 % (p < 0. 05). No difference was observed in other variables. The results of this study showed significant differences in about half of the studied indices between shaded and non-shaded regions, yet the change in traffic variable did not determine any decreasing or increasing trend of shadow effect on road pavement quality.

Mangrove forests are one of the most beneficial ecosystems that have lost more than 50% of their primary extents. Because of uncontrolled degradation, many countries go beyond standard measures of mangrove forests protection and produce standard seedlings to afforest for higher success rates. Therefore, the aim of this study was to investigate the effects of species, irrigation, and light regimes as well as their interaction on vegetative growth of grey mangrove (Avicennia marina (Forssk. ) Vierh. ) and red mangrove (Rhizophora mucronata (Lam. )) seedlings in the nursery setting. Seeds of mangrove trees were collected and planted in plastic pots during July and August 2008. Then collar diameter, height, and stem height to stem diameter (h/d) were measured as influenced by species, irrigation regime (every day, every other day, and three days in between) and light condition (shade and light) using a three-way analysis of variance. Results showed that the diameter growth in the red mangrove is more than 0. 38 mm than that of the grey mangrove (p < 0. 05). Interactive effects of species × light condition showed that diameter growth of grey mangrove and red mangrove seedlings are significantly different in the shade condition. Diameter growth of grey mangrove seedlings was higher in light condition than that of in shade (p < 0. 05). In shade, the stem height to stem diameter of seedlings was significantly higher than that of those measured it in light. Furthermore, the stem height to stem diameter as influenced by species × light condition was significantly different between two species and was also higher in shade condition compared with grey mangrove seedling (p < 0. 01). The results suggested that light provides more favorable conditions for the grey mangrove seedlings growth, whereas it is not beneficial for the red mangrove seedlings.

Knowledge on the area and amount of forest coverage at landscape scale can be one of the most important indicators in forest sustainable development. In this study, we used Landsat-8 full coverage imagery across the Guilan Province and the supervised classification method for forest canopy cover mapping in the summer of 2014. Field data were collected by a two-stage sampling method and 316 number of 0. 5-ha plots. Subsequently, information on the types of land use and the canopy density (the ratio of the level of forest floor lightness per unit area) were recorded. With an overall accuracy of 91. 8% and kappa coefficient of 0. 80, results showed that 498804 ha of the total land area of Guilan Province is covered by forests, from which dense, semi-dense, and scattered forests account for about 42. 1, 41. 5, and 16. 4% of the forested areas, respectively. This study demonstrated the negative effect of spectral similarity between farmlands with scatter and semi-dense forests in the accuracy of forest classification. This study demonstrated the proper performance of Landsat 8 data in providing thematic maps such as density and forest cover. Therefore, these data and information can be recommended for use in forest management decision-making, conservation, and restoration.

The way temperature affects the soil respiration remains still unknown, which causes uncertainties in predictions of future trajectories of the global carbon cycle. Temperature sensitivity of soil respiration (Q10) is a key indicator for estimating soil respiration feedback to global warming. The purpose of this study was to investigate the temperature sensitivity of total soil respiration based on temporal changes in soil temperature and moisture contents in a beech-hornbeam stand. Therefore, we first determined 12 sample plots (six sample plots in the gaps and six under canopy cover) with 3×3-meter dimension. Sampling was conducted in three randomized points of each sample plot. At each sample point, soil respiration was monthly measured using a closed dynamic chamber throughout the year. The results showed a significant correlation between Q10 and some environmental variables, including soil temperature and moisture contents and also air temperature (p < 0. 05 and p < 0. 01). In addition, the temperature sensitivity of soil respiration was higher under canopy cover plots than that of in gaps. Although the lowest soil respiration rate was observed in winter (0. 94  mol m-2 s-1), the highest temperature sensitivity of soil respiration in this season (4. 23) was observed under canopy cover plots. Thus, a slight increase in soil temperature, especially in winter, would result in a significant change in the rate of respiration of the entire soil and the adoption of a carbon cycle equilibrium in the forest stands of this area.