مجله جنگل ایران
سال سیزدهم شماره 1 (بهار 1400)

The aim of this study was to investigate the effect of seed maturation on germination, growth and seedling quality index of common ash (Fraxinus excelsior L.) in Kelardasht forest nursery. In 2017, the seeds of immature in late August and the seeds of mature in late November were collected and following stratification in moist sand were sown in nursery bed in mid-Feberaury each with three 100-replications . From the mature seeds, some of them germinated in 2nd year (April 2018) and the seed germination, biomass and quality indices of their seedlings were statistically (paired t-test) compared with the results of immature seeds germinated in spring 2017. The highest percentage of cumulative germination allocated to the immature seeds, followed by mature seeds germinated in 2nd year. Due to the lack of germination of most of the mature seeds in spring 2017, showed the seed dormancy, their germination traits were not considered in the statistical test. Germination percentage, mean germination time and germination speed and also, dry biomass, root biomass, root length and seedling quality index in immature seeds were greater than those in mature seeds germinated in second year. Generally, it is best to collect the seedlings of immature seed in order to achieve the optimum germination and growth, because the mature seeds are often dormant and unable to germinate during the first growing season. If mature seeds are supplied, it is advisable that these seeds to be stratified until spring of the second year.

Rowan is a tree with a very limited distribution in the upper treeline in the Hyrcanian forest. In this study, seven habitats of this tree from east to west of the Hyrcanian forest were identified and seed germination behaviors and diversity in leaf morphological traits were evaluated. Multivariate analysis showed that the studied populations were not differentiated from each other in terms of morphological traits. The results of germination percentage showed that in cold treatment and hot and cold treatment, germination reached about 100% after about 70 weeks. The germination rate in the cold treatment reaches its peak at week 55 and about 90% of the seeds germinate at week 55. In the hot and cold combination treatment, although before week 50 the germination rate reaches its maximum with a cumulative germination percentage of about 40%, but from this week to week 55 the germination rate again slows down and from week 55 to week 60 second drops. It experiences its peak with about 80% germination. The results of the present study showed that the Rowan tree species does not have a high morphological diversity in its habitats in the northern Iran. Due to lack of knowledge on the long-term seed germination of this tree, mountain nurseries have been unsuccessful in producing seedling.

One of the problems of Zagros forests is the phenomenon of oak dieback, that its control is one of the important factors to prevent the destruction of forests. One of the proposed solutions to control this phenomenon is implementation of sanitary cutting. Remote sensing data has made it possible to monitor the areas involved in this phenomenon. The purpose of this study was to investigate the spectral behavior of exposed dieback forests before and after sanitary cutting in Guilan_e_Gharb forests. To monitor the pattern of spectral behavior, Landsat 8 satellite images were used from one year before sanitary cutting (2013) to 2018. After atmospheric correction of satellite images, NDVI, WDVI, SAVI and NDWI vegetation indices were prepared using spectral ratios of the main bands. A total of 30 points were selected scattered throughout the region and the spectral value of near-infrared band and vegetation indices were extracted at the selected points. The results showed that the spectral behavior had an upward trend until the last year of monitoring. The results of comparison of means test on the data of 2013-2018 showed that the differences between the means of all bands were statistically significant. Although the spectral behavior of vegetation indices is also affected by climate change and rainfall, but due to the increasing trend of near-infrared and vegetation indices during the years after sanitation cutting, a large part of the changes can be contributed tothe result of sanitary cutting and improvement of the forest conditions.

Currently, biodiversity in the Zagros region faces two serious threats including land use changes and unstable harvesting. These factors both alone and in combination, can lead to severe and irreversible damage to the forests. Therefore, the restoration, reconstruction, protection and sustainable management of forest ecosystems in the Zagros vegetation area has always been the main(basic) concern of activists and officials in this basin. Therefore, the present study was conducted to explain the criteria and indicators of sustainable forest management in Zagros vegetation area from the point of view of experts, using content analysis technique. The research data were collected through semi-structured interviews. People involved in research includes specialists, manager scientific and executive experts and experts related to Zagros forests.For data analysis, MAXqda12 software was used. The research findings indicate that among the most important criteria identified for sustainable management of forests in the Zagros vegetation from the point of view of experts are the criteria of forest size and production capacity, conservation functions, ecosystem conditions, conservation criteria biodiversity, economic criteria. Social criteria, criteria of laws and structures and educational and extension criteria. It should be noted that for each of the relevant criteria, the indicators corresponding to that criterion were also identified (8 criteria and 18 indicators). Our findings indicate that, the most important indicators for sustainable management in the Zagros vegetation region are the indicators of law-making and total forest area belonging to the criteria of laws and organization and to the criteria of ecosystem conditions, respectively. The results of this study can be used in line with principled policies in the forest resources of the Zagros Basin and for planning, decision making and success in this field.

Species selection and suitable planting methods are essential for creating plantation and green space. This is important specially in arid and semi-arid regions. The object of the present study was to investigate the growth and primary establishment of four tree species using four different soil remediation treatments in Semnan City. These treatments were applied to two-years-old saplings in three replications and five observations in each replication and the quantitative and qualitative characteristics of saplings were measured and recorded during the experimental period. The results showed that straw mulch (together with stone cover) caused the highest collar growth in all investigated species, while the usage of hydrogels and zeolites did not have a significant positive effect on the sapling growth and decreased the growth in some cases. Compared to control soil (sandy-loam), the modified soil texture treatment (loam soil) did not change the collar diameter, height and total length of lateral branches of Melia and Cupressus saplings, but it reduced the diameter growth in Pistacia and Quercus saplings. The highest rate of survival in all investigated species was observed in control and straw treatments. The results of this study showed that Pistacia and Melia had the highest and lowest survival rate, respectively. However, Melia had the highest height and collar diameter growth amongst investigated species with maximum growth under straw treatment. Contrasting other species, Quercus has experienced a significant decrease in collar diameter and height (in all treatments specially hydrogels and zeolites) after June and has progressed to shrub form.

Forest road networks play an important role to achieve management goals in forest ecosystems and despite of implementation of the forest logging ban, their protection and maintenance cannot be stopped. Therefore, in order to allocate budget and prioritize the maintenance planning, designing a reliable model for predicting the condition of road pavement failure has great importance. The purpose of this study is to predict the performance of road pavement for planning its maintenance management using Markov chain theory. In the present study, 185 road sections in the forest roads of West Haraz were selected and the data of pavement, surface and roadside conditions were measured in different plots during 2015-2018. Then, the functional quality of the road was evaluated by the PCI index and the developed index for forest roads (FRPCI). The pavement quality was classified into five classes: excellent, good, average, bad and broken. After assessing the current situation, the road future situation was predicted over a period of ten years using the Markov chain. The results of this study based on the Markov chain model showed that the process of road decline from the upper class to the good is faster than the process of changing it from the middle class to the poor. Given that a large amount of capital is allocated in forest management plans to road construction and maintenance, need to speed up the protection and maintenance of the road, especially on better quality roads is vital. According to the study, the Markov chain model has sufficient capability in predicting the process of road deterioration and road network maintenance programs.

The aim of this study was to investigate the allelopathy effect of Prosopis juliflora species on emergence, vigority, gemole and plumule length of two important forest species in southern Iran, Hormozgan province. For this purpose, in the summer of 2020, 15 seeds of Acacia oerfota and Acacia tortilis were planted in the soil collected under, margin and four meters from the canopy edge of Prosopis juliflora and also in the soil mixed with leaf powder of Prosopis juliflora (0, 20, 40, 60 and 80 gr/kg leaf powder in soil) and irrigated with distilled water and their emergencewas recorded once every two days. Finally, gemole and plumule lengths of germinated seeds were measured and the variables were analyzed using GLM statistical analysis at 95% level. The results showed that the emergence percentage in A. tortilis species (20.74%) was significantly higher than A. oerfota species. The gemole length of A. oerfota species (5.14 cm) was longer than A. tortilis while in the soil mixed with prosopis leaf powder, the gemole length in A. oerfota was lower (0.53 cm) than it in A. tortilis. The length of gemole and Plumule in the open area with values of 5.88 and 4.34 cm was significantly higher than their values in the soil under the crown of Prosopis juliflora. Emergence percentages (17.5%), vigority (13.40) and the length of plumule (4.22 cm) were lower in the soil mixed with prosopis leaf powder than those in control treatment. The interactions of species×soil position on vigority (4.40), gemole and plumule length (3.11 and 2.48 cm) showed that the two variables of gemole and plumule length were affected by the soil collection site and had its lowest value under the canopy which it was observed in prosopis leaf concentration treatments. The results showed that A. oerfota species was strongly influenced by Prosopis juliflora allelopathy, therefore, it is recommended to prioritize afforestation with native species and, if possible, to avoid the plantation of Prosopis juliflora in the southern sensitive ecosystems.

The purpose of this study is to investigate the vegetative and soil characteristics of ‎natural and ‎plantation stands of Nitraria schoberi on the ‎western shore of Lake Urmia. In this study ‎in ‎natural stands of N. schoberi (Jabal Kandi region) 40 plants and in plantation stands of ‎N. ‎schoberi (Jabal Kandi and Seporghan regions) seven transects with unequal lengths (containing ‎‎15 ‎individuals) were randomly selected along the planting rows. The characteristics of total height, ‎collar ‎diameter, large and small diameter of the crown, and the health of seedlings were then measured. ‎In natural stands of N. schoberi, seven soil samples were randomly taken from ‎‎the vicinity of the seedlings. In plantations stands with sampling in each transect, adjacent to the ‎‎first, eighth (middle), and last seedlings of each sample line, soil samples were taken from 0-20 cm ‎‎depth, and after mixing these three soil samples, a sample was prepared, and soil physicochemical ‎‎properties were examined in the laboratory. Results showed that there was a significant difference ‎between the vegetative characteristics of total height (m) and the average crown diameter (cm) of N. ‎schoberi seedlings in Jabalkandi natural stand (7.1±3.0 m and 463.20±0.91 cm) with two other ‎plantation ‎stands, Jabalkandi (99.03±0.0 m and 287.5±87.37 cm) and Seporghan (50.01±0.0 m and ‎‎90.4±50.31 cm). Plantation ‎ and natural habitats of N. schoberi in Jabalkandi region had poor soil ‎fertility, high pH and lighter soil. The results of this study showed that in planting N. schoberi ‎species to control the wind erosion, it is very important to pay attention to the physical and chemical ‎properties of the stand soil, and this species reacts negatively to heavy texture and high amounts of ‎clay.