مجله جنگل ایران
سال سیزدهم شماره 4 (زمستان 1400)

The most common models for estimating rainfall interception are physical-based models, of which Gash models are the most widely used. Therefore, this study aimed to compare the efficiency of revised Gash models in estimating the rainfall interception of Fagus orientalis Lipsky in Siahkal forests, Gilan province. During the one-year measurement period in the study plot (March 2015 to March 2016), gross rainfall, throughfall, and stemflow values were collected and the amount of rainfall interception was computed. For modeling rainfall interception, Gash-1 and Gash-2 models were selected, and the performance of these two models was evaluated during time scales: annual, leafed, and leafless periods. The results showed that in general, canopy and trunk echohydrological parameters were obviously different amongst time scales. In all time scales studied, the Gash-2 model performs better than the Gash-1 model, and the most appropriate performance of Gash-2 model is in estimating annual interception (estimation error: +8.8%; efficiency coefficient: 0.92). In summary, it can be said that forest ecohydrological processes in deciduous broadleaf stands should be studied separately during different time scales, because the ecohydrological response of canopy cover in different time scales is varied. Also, different models in different time scales do not have the same performance. Hence, further studies are needed to determine the efficient models in each time scale of each forest stands, and by obtaining the appropriate model, we can help to accurately estimate the interception in Hyrcanian forests.

Tourism development by planning the principles of access roads can help the management and development of villages in natural and protected areas. This study aimed at planning and developing the access roads to achieve the tourism and rural areas as the recreational attractions in Arasbaran protected area. For this purpose, the road network options were designed for three different scenarios to access the recreational and rural areas in GIS environment and evaluated in terms of technical, environmental and socio-economic aspects. In the next stage, the existing road network was modified according to the optimal-designed road options. Finally, the modified versions of the existing road network were proposed for tourism development and management in the region. Thus, the variants of the existing road network, the optimal-designed road network and the modified-road network were evaluated and compared. Moreover, among the designed options, the 10th option in three different scenarios to access the recreational areas and the minimum, medium, and maximum villages with densities of 4.17, 4.93, and 5.86 mha-1, respectively, was chosen as the optimal option to modify the existing road network. Finally, the modified road networks with densities of 3.98, 4.66, and 5.55 mha-1 and accessibilities of 72.7, 76.19, and 78.33 percent were proposed for these three scenarios. According to assessment and comparison of the variants, the optimal-designed road networks and the modified road networks were identified as the better alternatives compared to the existing road network. Tourism management and development in Arasbaran by principled planning and development of access roads can lead to prosperity of economic activities and improve the rural development in this area.

Agroforestry has been implementing for a long time in Zagros forests. Understory cultivation of Cultivating perennial plants (such as Ferula assa-foetida) rather than annual plants (such as Triticum spp) may help to reduce the soil loss. This research aims to evaluate the financial profitability and soil loss resulting from two alternative agroforestry practices of forest-asafoetida and forest-wheat in Tang-sorkh region of Kohgiluyeh and Boyer-Ahmad Province. Financial analysis was performed using a cash flow diagram, land expectation value (LEV), equivalent annual value (EAV) and annualized return on investment (ROI) criteria. The annual soil loss was calculated using a universal soil loss equation based on rainfall erosivity, erodibility, the length, and the slope of the land, as well as the type of vegetation management. The soil conservation data were collected and measured in landform units. The soil samples were collected at (0-30cm) and (30-50cm) of landform units within the agroforestry practices areas. Economic information was compiled using the farmers' census method and the semi-structured questionnaire. The results showed that the annualized ROI in the forest- Asafoetida practice (32.6 %) is by far much higher than forest-wheat practice (-7 %). In addition, the results indicated that the average of soil erosion in forest-wheat practice (18.5 t ha-1 yr-1) is 6.6 times higher than the forest-assafoetida practice (2.8 t ha-1 yr-1). Future research will explain why farmers continue to apply loss-making forest-wheat practice.

This research aimed at studying the seedling emergence and survival rate of Pistacia atlantica, Acer monspessulanum and Amygdalus orientalis by direct seeding in Dalab forests of Ilam with two aspects and five seeding positions (nurse type). For this purpose, six sites were selected in the north- and south-facing slopes with the same altitude. In each site, one transect was established perpendicular to the slope, and the seeding positions including “tree”, “shrub”, ‘bush”, “rock” and bare spaces, by observing three replicates were determined. At each seeding position, 12 holes were dug and the seeds of the mentioned species were planted. The number of seedlings during the spring and summer of 2018 and 2019 years was counted. According to the results, the number of seedling of P. atlantica decreased in the second year compared to the first year and in summer compared to spring. The highest percentage of holes with seedlings of P. atlantica was found in northern aspect and under tree crown and next to the rock. The highest percentage of holes with A. monspessulanum seedlings was under tree crowns and shrubs. A. orientalis did not react to any of the examined factors. The most and least share of the seedling emergence were belonged to P. atlantica and A. monspessulanum, repectively. It was concluded that the rate of seedling emergence changes under the effects of aspects and seeding positions, so to increase the emergence rate of seedlings, it is better to sow in the field in more suitable seeding position in any aspect.

The aim of this study was to identify and analyze the management issues related to the mangrove forests of Qeshm Island and to investigate the relationships and collaborations between government agencies using the network analysis method. In order to collect information and data related to the research topic, they referred to the relevant agencies and local communities in this regard and were asked to list the government agencies involved in the management of mangrove forests. Then, a network analysis questionnaire was prepared based on a review of three types of communication networks (referral, cooperation, trust) between government agencies involved in mangrove management and was completed by their representatives. After completing the data and entering them into Excel software, the data were entered into UCINET6.718 software for analysis and after generating a one-dimensional matrix, macro and micro indicators of the network such as density and centrality were measured. The results of graph analysis using NetDraw software showed that all micro and macro indicators in the cooperation network are better than the reference network and in the trust network are better than the cooperation network. Also, the cooperation and participation of provincial government agencies along with the sub-managements of the Qeshm Free Zone Organization are other strengths of these networks, which can be used to expand the participatory projects in the management of these forests with the participation of local communities.

The aim of this study was to investigate the possibility of increasing the germination traits (germination and rate percentage) and vegetation characteristics of 3-month-old seedlings of Betula pendula (plumule and radicle length, collar diameter, fresh and dry weight of root, leaf area) by applying nano-priming and magnetic field. Seeds were collected from the Siah- Marzkouh area, 18 km from Gorgan-Golestan, Iran and after disinfection they were primed (soaked)  in a 1% solution of nano-chitin, nano-chitosan and nano-cellulose, and then sown. Magnetic treatment was applied to the seeds at three levels of 20, 30 and 40 mT at 1, 10 and 20 minutes and were sown immediately. A number of seeds were primed with all 3 nanomaterials after being exposed to the magnetic field (with the previous dose and time) and then planted. The results showed that among all the applied treatments, 1 min magnetism in 30 mT and then 2 hour seed priming with 1% solution of nanocellulose, were the best, In a way that increased the germination percentage (1.58 times), germination rate (1.9 times), number of leaves (1.2 times), leaf area (1.84 times) and root length (1.4 times) compared to the control (no treatment). The 20-minute magnetic treatment of seeds at 30 mT intensity and then the two-hour seed priming with 1% nanocellulose gave similar results. Two seed treatments (10 and 20 minute) in 30 mT (without nanopriming) are also recommended after these two treatments.

The dependence of rural livelihoods to natural resources leads to a wide range of violations in this field. Studying the legal cases of natural resources is one of the important issues of the Forests, Rangelands and Watershed Organization of the country that their analysis can lead to the identification and reduction of the factors resulting in the destruction of natural resources in the country. In this study, using the descriptive-analytical method, quantitative content analysis approach, frequency and rate of violations recorded in 333 cases in a period of 15 years between 2006 up to 2020 in four villages of Sardasht customary area of ​​Lordegan township in Chaharmahal and Bakhtiari province has been studied. The results showed that the main violations are related to cutting, uprooting and burning of seedlings and trees and carrying firewood and charcoal, which accounts for 68% of violations. During the study period, 12558 trees and seedlings were cut down or destroyed by intentional fire and 34831 kg of wood and charcoal were illegally transported. Also, 103,300 kg of charcoal has been discovered in illegal coal kiln. Therefore, the most important factors in the degradation of forests in the region can be considered cutting down trees for firewood and charcoal. According to the results, there is a significant difference between the frequency of violations in the period and the villages. Developing rural infrastructure and planning for appropriate employment to reduce the poverty, continuous control and monitor of security officers, and tailor the violations to crime can reduce the severity of existing damage.

This study aimed to analyze tree diversity and tree crown and stem condition as two indicators of forest health in the Masouleh forest watershed, Guilan province. Field data collection was performed using cluster sampling based on Forest Health Monitoring (FHM) method. A total of 5 clusters including 20 subplots in the mixed beech (Fagus orientalis Lipsky.) forest stand were established. Within each cluster, quantitative and qualitative characteristics of existing trees such as diameter at breast height (dbh), total height, canopy diameter, density, and percentage of crown dieback and stem quality were studied and measured. To assess the tree species diversity, species biodiversity indices, richness and evenness were calculated in each cluster. Based on the results of the analysis of variance in 95% confidence level, there are no significant differences in the species diversity indices between the five different clusters (P>0.05). The highest and lowest value of the species diversity indices were measured in clusters 2 and 3, respectively. The largest change in the species diversity occurred at cluster 4. The results showed that all clusters in the study area had good status in terms of the species diversity indices. The amount of canopy drought in some species was proportional to the trend of canopy diameter changes and Buxus hyrcana Pojark. and Diospyros lotus L. species had the highest percentage of canopy drought (approximately 17%). Regarding the quality of stems, more than 80% of the trees in the forest stand have good quality. It is concluded that the health status of the studied ecosystem in terms of the level of tree diversity and tree crown and stem conditions is desirable.