جستجوی مقالات مرتبط با کلیدواژه « D » در نشریات گروه « جنگلداری »

 Forests are one of the most significant sources of species diversity in the biosphere, playing a crucial role in protecting endangered species. With a total of 115 indigenous plant species, Hyrcanian forests are considered one of the most valuable ecosystems in Iran and the world. Deadwood is one of the significant structural characteristics of these natural forests. Deadwood, as habitat trees, plays an essential role in maintaining biodiversity. Saproxylic species are invertebrates that depend on rotting wood, deadwood (standing or fallen), fungi, and other living organisms during part of their life cycle. Therefore, this study investigates and analyzes the need to replace the proposed word “خشک دارزی” instead of “saproxylic.”

 The method in this study involved a review of previous studies and the authors’ research related to the comprehensive plan of saproxylic species diversity in northern Iran. Based on this, the study investigates and evaluates the most important reasons for using the Persian word “خشک دارزی” instead of “saproxylic” in seven different cases. These include a specialized review of the word “saproxylic,” examining the distinction between obligatory and optional users of deadwood, estimating species related to deadwood, analyzing the variables affecting the abundance of saproxylic individuals, the relationship between the loss of biodiversity of Saproxylic species and the absence of deadwood, forest plantations and saproxylic individuals, and comparing the word “خشک دارزی” with other similar words.

 The specialized examination of the word “saproxylic” showed that this term forms the basis of biodiversity assessment in deadwood and describes insects living in decaying wood. Saproxylic organisms (hereafter: “خشک دارزی”) directly and indirectly use deadwood as a source of energy or habitat. Twenty to twenty-five percent of the insects living in the forest are species related to deadwood. The results of examining the variables affecting the abundance of Saproxylic individuals showed that deadwood volume, the degree of deadwood decay, and the volume of living trees had significant effects on the frequency of Saproxylic individuals. Various studies also showed the relationship between the loss of biodiversity of Saproxylic individuals and the absence of deadwood, with traps (window and pit) always installed where deadwood is present. On the other hand, although plantations for wood production are one of the most important sources of wood on a wide scale, there is no sign of deadwood and, consequently, no presence of saproxylic individuals in these areas compared to natural forests. While the meaning of deadwood is a dried tree, in nature, deadwood is not always a completely dead tree. In many cases, only part of the trunk or crown of the tree is dead, while other parts are healthy. This term is known to all experts in forest ecology as referring to any part of a completely dead tree, aligning with the term deadwood.

 Therefore, the word “خشک دارزی”instead of “Saproxylic” can effectively describe this category of species in the Persian language. Finally, the necessity of replacing non-Persian words with suitable Persian words and equating these words in scientific research writings, while preserving their expressive meaning in Persian, can be a positive step towards specialized vocabulary.

In today’s urbanized world, the preservation of the environment and urban green spaces has become a major concern for citizens and governments worldwide. This study aims to emphasize the importance of non-governmental organizations (NGOs) and charitable foundations in the reforestation and afforestation of vegetation cover. Using a comparative approach, the study examines global and Iranian experiences and evidence, and reviews executive and functional records in the field of natural environments, vegetation, and green spaces through library surveys, internet research, and inquiries made to domestic and foreign institutions and organizations.

This study introduces some of the most significant charitable foundations and NGOs in the field of nature and environmental protection worldwide. These organizations, mainly based in the United States and England, have completed their education and entered the stage of implementing initiatives for the restoration of local forests, world forests, forestry, environmental protection, increasing biodiversity, climate change, and other related topics. Additionally, the study examines the forest reforestation and afforestation goals and implementation methods of the most important charitable foundations in countries similar to Iran, including Armenia, Turkey, and Lebanon, as well as different countries such as China, South Korea, Norway, Germany, Brazil, and Canada. The study also describes the activities of internal organizations such as Nature, Pama, Roostagol Varjin, and Algan, and analyzes their significant actions and measures taken. Finally, the role of certain charities that have taken action in restoring and developing vegetation in the country is discussed.

The results of this study showed that among the countries similar to Iran, the “Tema” Institute in Turkey, with a 30-year history at the national and international levels, has carried out significant activities in the fields of forest restoration, education, climate studies, and biodiversity. Among different countries, the “Terra” Institute of Brazil has also undertaken important measures in the fields of reforestation, wildlife return, and vegetation restoration, aiming to restore the region’s forests, environment, and promote sustainable rural development over a period of 20 years. Among domestic institutions, Roostagol Varjin has made a significant contribution to the reforestation and afforestation of vegetation and urban green spaces. All these institutions and foundations share common goals in their field of activity, and through the support and participation of these groups together, the great goal of vegetation reforestation and afforestation can be realized. Therefore, it is not possible to determine which activity is superior; all of them are necessary in society. In fact, for the development of this task globally and even within a country, we need a powerful society, and a powerful society requires the participation of more people, and the grounds for this participation must be provided.

To improve the status and activities of NGOs, several measures can be taken, including providing information and training, strengthening environmental advertisements on radio and television, expressing environmental problems, and providing banking and legal facilities for these organizations. Additionally, introducing native species for planting in each region, empowering local communities, establishing research units and experts in the field of reforestation and afforestation, and promoting communication between NGOs, donors, and the government are the most important management measures for restoring and developing vegetation at the national level.

Estimating forest tree structural attributes such as height and diameter at breast height (DBH) is crucial for understanding the structure and management of forest resources. One important method for estimating these parameters is the individual tree detection (ITD) method using appropriate remote sensing data, such as airborne LiDAR data. However, it should be noted that different ITD methods have various limitations and capabilities and react differently to changes in forest tree species and the vertical structure of the canopy.

This study presents a hybrid individual tree detection method that combines raster-based and point-based methods in a multi-scale framework to identify single trees from LiDAR data. In this method, tree crown scale levels are obtained from morphological filters in the canopy height model (CHM). Segmentation is then performed using a multi-scale method, and the results are merged. To better separate adjacent and understory trees, the point cloud inside the segments is analyzed using the probability density function, and tree crown segments are modified. After detecting single trees, DBH and height parameters were estimated using ground control data and extracted features from LiDAR data with machine learning algorithms, including random forest (RF), support vector machine (SVM), and cubist (CB), in the form of 10-fold nested cross-validation (10-fold NCV). The Boruta feature selection algorithm was used to identify the most important metrics based on the LiDAR point cloud, which played an effective role in improving the performance of machine learning algorithms. Due to limited access to LiDAR and ground data from Iran’s forests, this study uses the NEWFOR single tree detection benchmark dataset, collected from forests of the Alpine region with a combination of different tree species and vertical canopy structures.

Although understory trees cannot be extracted with the same accuracy as overstory trees, the results of this study showed that, on average, the developed multi-scale individual tree detection (MSITD) method detected 89% of the tree crowns in the highest height layer and the highest number of small overstory trees with a detection rate of 48% in the lowest height layer (2-5 meters). The analysis of the machine learning algorithms’ results in estimating forest structural attributes showed that, despite slight differences in performance, the SVM algorithm performed better than the RF and CB algorithms in estimating both height and DBH attributes. For the height attribute, the mean values of RMSE, rRMSE, and R2 in the SVM algorithm were 1.75 m, 9%, and 0.85, respectively. For the DBH attribute, the values obtained for RMSE, rRMSE, and R2 were 4.74 cm, 19%, and 0.78, respectively.

The evaluation of the results showed that the methods presented in this study for identifying single trees and estimating forest tree structural attributes have high potential for practical applications.

In recent decades, the Khamir and Qeshm mangrove forests in southern Iran have suffered significant destruction due to various human activities, including the construction of docks, commercial and tourism ports, deforestation, and unplanned tourism development. These forests, which provide valuable ecosystem services, have faced indiscriminate and unplanned development, as well as insufficient attention from local communities. Therefore, understanding the spatial distribution of plant species in this area is crucial for effective planning and enhancing the protection of these valuable biological resources. This study aims to identify suitable areas and model the presence of the mangrove tree species Avicennia marina (Forssk.) Vierh. in the Khamir and Qeshm mangrove forests to facilitate the restoration and proper distribution of this species.

The habitat suitability map for A. marina was prepared using MaxEnt modeling. A total of 234 points were randomly recorded using the Global Positioning System (GPS). To investigate the spatial distribution of A. marina, various environmental factors affecting its geographical distribution were analyzed using ArcGIS 10.8 software to generate maps and environmental variables. The environmental variables were selected based on theoretical foundations, previous studies, and expert opinions. The model included 18 climatic variables and 5 physical variables affecting the distribution of A. marina. The physical variables included maximum wave height, beach slope, tidal fluctuations, water salinity, and beach material (sandy-gravel, muddy, back beach (sand material)). All layers were prepared in ASCII format with a cell size of 1 km, and MaxEnt 3.4.4 software was used for modeling.

The area under the curve (AUC) obtained from the MaxEnt algorithm indicated excellent predictive power for the presence of A. marina in the study area, demonstrating the model’s ability to distinguish between suitable and unsuitable areas. The overlap of training and test data also confirmed the model’s accuracy. The contribution analysis of each environmental variable in the model showed that maximum wave height, annual average temperature, tidal fluctuations, and water salinity were the most influential variables. Specifically, maximum wave height and annual average temperature had the largest influence on the distribution of A. marina, while the minimum temperature of the coldest month had the least effect. The response curves indicated that maximum wave height (1 to 2 m) and average annual temperature (26.8°C) were the most important independent variables, with an inverse relationship to the probability of A. marina presence. As wave height and average annual temperature increased, the probability of species presence decreased. The suitability map for A. marina in the Khamir and Qeshm mangrove forests showed that the highest suitability was in areas with minimal wave height and less exposure to tidal fluctuations. Favorable areas for the presence and development of A. marina included the northern areas of Khorkhoran Islands, Mardove Island, and the northeast of the Khamir-Lashtghan habitat. In general, the species was more dispersed in areas with low wave height and minimal water level fluctuations.

The study provides key information on the impact of environmental variables on the distribution of A. marina, offering an important strategy for protecting the biodiversity and valuable resources of the species in the Khamir and Qeshm mangrove forests. The suitability map serves as essential information for planting and reviving these natural habitats.

 Evaluating the management process of Extra-Hyrcanian Forests in Iran is crucial for identifying the strengths and weaknesses of these forests’ management. To achieve this goal, the first part of this article, published in volume 31 of the Iranian Journal of Forest and Poplar Research, outlined the management process of Extra-Hyrcanian Forests in five distinct periods. The first period spans from the initial organization to the establishment of the Forestry Company in 1949, a time characterized by minimal attention. The second period, from the establishment of the Forestry Company to the beginning of the 1960s, marked the inception of attention and the creation of the first organizations. The third period, from 1960 until 1972, saw the commencement of scientific management through the preparation of forestry plans. The fourth period, from 1961 until 1978, witnessed forestry restoration and the development of green space. The fifth period, from 1973 to 1978, focused on the protection and reclamation of forestry plans. The current article examines the management process of these forests from 1979 to 1996.

 The information was compiled from various sources, including reports, implemented forestry plans, identification and semi-detailed studies, field observations, and over 30 years of experience in the Extra-Hyrcanian Forests. After the Islamic revolution until 1996, all types of management methods were tested in the Extra-Hyrcanian Forests without pathology. However, in 1996, a deadline plan was demanded from the organization managing these resources to address the challenge of forest mismanagement in the region. The custodian organization also introduced the general approach of managing Extra-Hyrcanian Forests by presenting a plan. Therefore, although various activities were applied in the management of Extra-Hyrcanian Forests from 1979 to 1996, the details are stated in the following text.

Since 1979, the implementation of protection and reclamation of forestry plans was pursued only in two provinces, Fars and Khuzestan. After a three-year hiatus, from 1983, the Forestry Technical Office resumed the preparation of forestry plans by adding a social and economic component to the studies and reviews of previous plans outside the north (Extra-Hyrcanian). This resulted in the implementation of 15 plans in the Zagros area, six plans in the Irano-Touranian area, one plan in the Gulf and Omani area, and two plans in the Arsbaran area from 1983 to 1995. Regrettably, none of the plans were fully implemented and did not achieve significant success in practice. Regarding the production of saplings and plantation in the aforementioned vegetation areas and during the mentioned time period, statistics have been presented that do not align with the existing reality. Also, in the Gulf and Omani region, 797.75 hectares of man-made forest parks were constructed, and 2069 hectares of unique forest stands were identified and managed as forest reserves. From 1985, the preparation of exploitation model plans for the exploitation of non-wood forest products began. Despite the shortcomings in the model plans, the minimum standards set in the plans were not clearly observed, and the rehabilitation obligations outlined in the written plans were not implemented.

 In summarizing the performance of this period, it can be stated that the relevant offices and authorities continued to follow up on past trials and errors without any coordination and cooperation with each other, operating completely independently.

Reproduction (regeneration) is a fundamental process that drives the dynamics of a forest, occurring continuously in a healthy and natural forest with a specific spatial and temporal pattern. Natural regeneration poses significant challenges in Zagros forests, Iran. This research was undertaken to examine and analyze the current state of reproduction of tree and shrub species in the monitoring sample plots of Zagros forests. This study, while scrutinizing the species composition, origin, distribution curves, and health of seedlings and saplings, explores the interrelationship between reproduction and nurse species. It will serve as the foundation for long-term studies that determine the temporal changes in reproduction and its characteristics in the Zagros forests.

This research was conducted in the permanent monitoring plots of Zagros, spanning from West Azerbaijan to Fars province. A total of 120 sample plots of 100 square meters were studied within these plots. Each province had 30 studied sites in the typical forests, with 10 of them located in the protected forests. The variables studied included reproduction density by species, origin and type of reproduction, nurse species, height of seedling, terminal bud, and health status of reproduction. A height of 0.5 meters was set as the criterion to distinguish reproduction. The t-test was used to compare parametric data in two groups, while the Kruskal Wallis and Mann-Whitney U tests were employed for non-parametric data.

In the studied area, the reproduction of 20 forest tree and shrub species was recorded, and the density of seedlings and saplings was calculated to be 366 plants per hectare. However, the reproduction was not uniformly distributed, with 37% of the sample plots lacking reproduction. The abundance distribution diagram in the height classes revealed a decrease in the number of oak (Quercus spp.) and hawthorn (Crataegus spp.) reproduction with a height of less than 5 cm. Of the total number of recorded reproduction, 72.5% originated from seeds and 25% were shoots. Overall, 66% of reproduction was dependent on nurses, with oak, hawthorn, stone, and rock playing the greatest roles as nurses. Stones and rocks played a more significant role in the revival of seedlings. Cerasus microcarpa (C.A.Mey.) Boiss., Q. infectoria Oliv., and Q. libani Oliv. had the highest dependence on the nurse, while Pyrus spp., Daphne mucronata Royle, and Crataegus spp. had the least dependence on nurse species. Reproduction sheltered by nurses was significantly healthier than those without nurses. Also, reproduction sheltered by stones and rocks had a higher health rate than reproduction sheltered by trees, although this difference was not significant. Lonicera nummulariifolia Jaub. & Spach, Fraxinus angustifolia Vahl, and Acer monspessulanum L. had the worst condition in terms of reproduction. Despite the presence of mature trees, they had no reproduction (L. nummulariifolia and F. angustifolia) or had very low reproduction (A. monspessulanum). The results showed that the number of reproduction in protected sites was higher than non-protected sites. Although this difference was not significant, the reproduction in the protected sites was significantly healthier.

The results indicated that the reproduction in the Zagros forests is not in a normal situation. However, given suitable spatial and temporal conditions, reproduction occurs and establishes. Although in conditions of disturbance and overgrazing, reproduction attempts to survive by taking shelter near stones, pits, or under thorny shrubs, the conservation of the forest stand by maintaining the tree canopy (oak, hawthorn, and other species) and the forest’s natural structure provides the best conditions for the establishment and survival of reproduction, thereby ensuring the sustainability of the ecosystem.

Given the significance of investigating and monitoring riparian ecosystems, this study was conducted to identify and map the land cover, including tree and shrub species classes, around the Zarinehroud River in West Azerbaijan province, Iran. Recognizing that the separation of lands with high spectral similarity using single-time images is not precise, this study utilized a time series of satellite images, capitalizing on the phenological differences of plant species.

The research separated the land cover classes into two stages. In the first stage, the time series data from Sentinel 1 and 2 were used to map different classes of tree cover (natural, wood farming, orchard), shrub cover (natural, orchard), grass or pasture, agriculture, residential lands, soil, and water bodies. Given that seasonal changes in the images can provide valuable information about land cover classes, a one-year (2021) time series of Sentinel 2 optical images and Sentinel 1 radar polarizations for 2021, in the form of median in each season, were processed on the Google Earth Engine platform. The data were classified using four composites of input features and four classifiers. In the second stage, to separate the vegetation classes into Tamarix, willows, orchard, and poplar plantation, the trend of one-year changes of normalized difference vegetation index (NDVI), normalized green red difference index (NGRD), normalized difference red edge index (NDREI), and green normalized difference vegetation index (GNDVI) combined with HV polarization of Sentinel 1 radar in the form of median in seasons, was used as an input feature. The land cover map produced contained Tamarix, willows, orchard, poplar plantation, grass or pasture, agriculture, residential lands, soil, and water bodies.

In the first stage of classification, the input feature of NDVI (Monthly)_ Radar (Seasonal)_ Sentinel 2 (Seasonal) and the random forest classifier were the best feature and the most accurate classification algorithm, separating the classes from each other with an overall accuracy and Kappa coefficient of 88% and 0.85, respectively. In the second stage of classification, the NDVI index between the months of April and November enabled the separation of all four tree and shrub covers. GNDVI between December and April was the best indicator for separating willows. Also, between May to November, it effectively separated Tamarix. NGRDI was suitable between May and November for separating Tamarix and also separated the poplar plantations between April and November. The GNDVI index between April and September effectively separated the two categories of orchards and poplar plantations from Tamarix and willows. The map was generated using the mentioned input feature and random forest algorithm. The overall accuracy and Kappa coefficient obtained from the validation relying on ground samples and Google Earth images were 80% and 0.77, respectively. The main diagonal of the error matrix shows the highest separation between water, soil, and urban land classes. Among the vegetation classes, willows and agricultural lands exhibited the best distinction.

The variation in a plant’s phenology, encompassing leafing, blossoming, fruiting, fall, and sleep cycle, leads to changes in the values of vegetation indicators during the seasons, which can be utilized in mapping vegetation to enhance separability. Consequently, if tree and shrub stands are pure and exhibit a different phenological behavior from their neighbors, they can be distinguished with higher accuracy using time series of satellite images.

Different plants from different climates are collected according to the objectives of botanical gardens. Climate is one of the important ecological factors that has the greatest impact on the longevity of plants. Changing the location of the plant from a dry to a humid climate may cause stress and change in vegetative behavior. Therefore, the selection of plants for each region should be based on climate knowledge. The objectives of this research included investigating the effect of climate and nutritional treatments on the growth of wild almond (Prunus scoparia Schneider).

This research was conducted by two related experimental methods. One of which included investigating the effect of climate on the growth of wild almond in Nowshahr Botanical Garden in Nowshahr county in north of Iran and the other one was the nutritional treatments on the seedlings of the wild almond in the Garden. The investigated factors in the climate effect test included the species of wild almond, environmental indicators and soil. The nutritional treatments were carried out as a completely randomized factorial design in three replications in the nursery section that the test factors were three levels of calcium nitrate as foliar spraying with a concentration of zero (control), 5 and 7.5 mM and two levels of potassium sulfate as foliar spraying with a concentration of zero (control) and 6 mM. The time of conducting this research was from 2017 to 2022. The seeds of the wild almond species were collected from the heights of Ghatour valley from Rahal village to Ghatour district located in Khoy county, Iran with an altitude range of 1492 to 1873 meters above sea level. Some parameters related to soil, plant and climate were evaluated at the same time as the experiment started in Nowshahr and Khoy counties. After the seeds germinated and the seedlings emerged from the soil, nutrition treatments were carried out by spraying potassium sulfate and calcium nitrite.

The results of the experiments showed that Nowshahr's climate had a significant effect on the growth indicators of almond species from temperature, humidity, evaporation, sunny hours and ice days. The highest photosynthesis rate of 2.45 mg/fresh weight and the highest plant transpiration rate of 1.35 mmol/square meter per second were observed in Khoy climate. The lowest root length in Nowshahr Botanical Garden was 63.32 cm with the highest share of leafless branches at 60.98%. Correlation relationships of root length in the soil and the intensity of leaf fall (leafless branches) show a significant positive correlation at the 1% level with the amount of plant transpiration. The results of the test data showed that the use of potassium sulfate compared to the control seedlings, led to an increase in the amount of plant growth and, as a result, expanded the canopy width. In this research, the relationship between calcium absorption and transport in the plant showed that the reduction of calcium in the leaf tissues in the control seedlings decreased the resistance of the plant to maintain the leaves. Calcium foliar application increased the amount of calcium in leaf tissue in almonds. One of the effects of this phenomenon is the increase in the durability of almond seedlings to about 30%.

Foliar treatments of potassium and calcium nutrients, although to some extent increased the durability of almond seedlings during the experiment, but the growth disorders caused by the effect of climatic factors prevailed over the nutritional treatment. Therefore, the seedlings could not successfully adapt to the new environment even with the help of nutritional behavior.

The Hyrcanian forests in northern Iran exhibit diverse rainfall and air temperature patterns. Altitude above sea level is a crucial topographical factor that influences plant growth and development, prompting trees to adopt different morphological, anatomical, and physiological strategies for survival and growth at varying elevations. This study aims to understand the impact of altitude on radial growth and tree-ring width by examining the rate of radial growth of Oriental beech (Fagus orientalis Lipsky) across different age classes in three altitude zones: low, middle, and high altitudes of the Hyrcanian forests in Kordkuy and Asalem habitats.

t three selected sites, located at approximately 700, 1400, and 2000 meters above sea level, tree-ring cores were extracted from 62 beech trees using an increment borer. Following core extraction, the holes on the trees were completely sealed with grafting wax. The surface of each core was prepared using a sequence of 100-, 400-, and 1000-grit sandpaper. Tree-ring widths (TRWs) were measured using LINTAB 5 and TSAP software. Measurements were taken from one side of the core and then from the other side. The obtained TRW series were analyzed using statistical parameters such as sign test, correlation coefficient, and Student's t-test. After cross-dating, average TRW chronologies were prepared for each tree. This method was then used to match the trees within each site. TRW chronologies for each site were verified using statistical methods. A one-way analysis of variance (ANOVA) test was performed to compare TRW chronologies. Meteorological data such as rainfall and temperature were obtained from the nearest weather stations. Meteorological data for Kordkuy and Asalem were obtained from the Gorgan and Astara meteorological stations, respectively.

The findings demonstrated that the elevation gradient had a significant impact on the radial growth of beech trees. TRW in the examined habitats is influenced by elevation above sea level in trees aged 50 to 150 years. The average radial growth of these trees in the middle elevations of Asalem and the lower elevations of Kordkuy is substantially higher than in other altitude areas. The mean growth of trees aged 100-150 years in the middle elevations of Asalem was the highest, amounting to 3.98 mm. Statistical analysis revealed a significant difference between the TRW of trees aged 100-150 years in the highland of Kordkuy with a mean annual growth of 1.94 mm and the lowerland of Kordkuy with a mean annual growth of 2.97 mm. During this age period, no significant difference was observed between trees from the upperland of Kordkuy and the moderate altitudes of Kordkuy, but there was a statistical difference between trees from moderate altitudes and the lowerland. A comparison of trees aged 200-250 years revealed a statistically significant difference between Kordkuy and Asalem moderate altitudes. The mean radial growth of trees aged 300-350 years in the upperland and moderate altitudes of Asalem is 1.25 and 1.32 mm, respectively. Statistical analysis demonstrated that there is no statistically significant difference between the mean radial growth of trees aged 300-350 years in the upper and middle altitudes of Asalem and the lowerlands of Kordkuy.

This study demonstrated that radial growth and tree-ring width of beech trees exhibited notable variations along an east-west transect across the Hyrcanian forests. The observed variations in beech radial growth and tree-ring sensitivity along the elevational gradient highlight the ability of beech trees to develop adaptive functional traits in response to environmental changes.

Accurate digital elevation models (DEMs) are crucial for effective forest planning and management. Various methods exist for generating DEM data, with handheld mobile laser scanners being the most efficient and precise approach. The raw point clouds obtained from these scanners require several preprocessing steps, one of which involves separating ground and non-ground points. Errors in this part of the process can lead to the generation of an inaccurate digital model with high uncertainty and errors. Various algorithms, such as voxel-based segmentation, simulation filters, and deep learning-based approaches, have been developed for this purpose. This study evaluates the performance of the OBS algorithm in automatically separating ground points from non-ground points in handheld laser scanner data. The study area comprised five different sections within the Karaj Botanical Garden, covering a total area of 7.2 hectares. These areas contained forest stands characterized by heterogeneous structures and multi-story tree layers. Data were acquired using a handheld GeoSLAM laser scanner. To generate a reliable reference for evaluating the algorithm's results, ground points were manually separated. The performance of the algorithm was evaluated by comparing it with the manually separated ground truth using statistical metrics, including Matthew's correlation coefficient, Kappa coefficient, and Intersection over Union (IoU). The statistical metrics across the five study areas demonstrated the effectiveness of the OBS algorithm in separating ground points from non-ground points, with Matthew's correlation coefficient, Kappa coefficient, and IoU values of 0.895, 0.891, and 0.902, respectively. Additionally, the optimal voxel size for the algorithm was determined to be within the range of 15 to 22 centimeters.We conclude that the OBS algorithm, when configured with optimal input parameters, provides high performance in automatically separating ground points from non-ground points, especially in heterogeneous forested environments. The importance of configuring the optimal input parameters is also highlighted.

Forest roads are essential infrastructures for accessing and managing forest units. Sustainable road management requires accurate spatial information from the road network. Various methods, differing in accuracy, precision, efficiency, and cost, are available for providing the location of roads. Given the remote location of forest roads, the lack of reference stations, potential inaccessibility to online networks, and conditions affecting positioning error, it is necessary to investigate the efficiency of existing positioning methods.

In this research, we studied the accuracy of PPK, RTK, online platforms such as Shamim, GPS, and mobile apps in positioning 34 points on 5 km of forest roads in watershed No. 30 in the Hyrcanian forest. The coordinates were first extended to the study area using the rapid static method. After post-processing and determining reference points, the exact coordinates of all ground control points on the road were obtained through the direct method. Then, the coordinates of all points were measured three times using various methods.

The health survey's statistical results showed that the highest mean differences were 2.53 m and 2.38 m for GPS and mobile apps, respectively. The least mean difference was 0.048 m, 0.049 m, and 0.092 m for PPK, RTK, and Shamim, respectively. The RMSE amount showed that the results from GPS and mobile apps had the least accuracy, and the methods PPK, RTK, and Shamim had the highest. Based on the one-sample T-test and Wilcoxon’s analysis, the amount of differences was not the same within each method through the 34 investigated points. Accuracy analysis indicated that GPS, with a distance mean of 1.14 m, had the least precision, and Shamim and RTK, with 0.0621 m and 0.063 m, were the most precise methods. The analysis of variance showed that the mobile app, Shamim, and PPK had the highest convergence.

The results of this research indicate that the PPK method was the most accurate, and the Shamim method was the most precise. Therefore, these methods can be used for purposes such as optimizing the forest road plan and longitudinal profile that require accurate location information.

Nitrate (NO-3) is an important compound in plant nutrition. However, the leaching of large amounts of it can reduce soil fertility and endanger environmental health and quality of life.

This study was conducted to investigate the effect of rice husk biochar and different types of pure and mixed fertilizers on nitrate leaching from the soil of one-year-old potted saplings of Acer cappadocicum Gled (with an average collar diameter of 17.3 mm and a height of 19.72 cm). This research was conducted in Lajim nursery, north of Iran, using 19 treatments with three replications in a completely randomized design. The treatments included rice husk at 0.5% and 1% by volume, biochar of rice husk at 0.5%, 1%, and 2% by volume, cow manure at 0.75% and 1.25% by volume, and chemical fertilizer at two levels: 1) triple superphosphate 25, ammonium sulfate 18.75, and potassium sulfate 18.75 mg per kilogram of soil and 2) triple superphosphate 50, ammonium sulfate 37.5, and potassium sulfate 37.5 mg per kilogram of soil. The soil treatment of the planting bed (control) and the combination of treatments were also included. To collect drainage water for measuring the amount of nitrate leaching, potted seedlings were irrigated 20% more than the normal irrigation amount, and samples were taken in five stages (from April to September, once before adding ammonium nitrate fertilizer and four times after its addition). In the laboratory, nitrate concentration was measured by the spectrophotometric method. Statistical analysis was performed using R software, and a comparison of means was performed using Duncan's test.

According to the results, in the first stage of sampling, the highest concentration of nitrate in drainage water was observed in the chemical fertilizer level 2. In the second and fourth stages, it was observed in the combination of chemical fertilizer level 1 and 0.75% cow manure by volume, and in the third stage, it was observed in the treatment with 0.75% cow manure by volume. The highest pH value of the drainage water in the first stage of sampling was observed in the combination of chemical fertilizer level 1 and 0.5% biochar. In the second and third sampling stages, the control showed the highest pH value. In the fifth stage, the result was the same as the first stage. Also, the combination of chemical fertilizer level 1 and 0.75 percent cow manure caused an increase of 204, and 0.5% biochar caused a total decrease of 39.4 mg/liter of nitrate leaching.

The results of this research showed that the application of biochar causes a decrease in electrical conductivity and nitrate concentration and an increase in the pH of drainage water. Therefore, considering the beneficial effect of biochar in reducing nitrate leaching and soil salinity, which will definitely bring positive environmental effects, it is recommended to use rice husk biochar to produce seedlings in forest nurseries.

The implementation of the forest restoration plan in the northern region of Iran has led to an increase in efforts to enhance wood production through the cultivation of poplar seedling. Particularly, poplar trees hold a significant position among wood producers due to their distinctive features. The key consideration revolves around identifying suitable and cost-effective lands for planting fast-growing species. Purpose of this study focuses on assessing the land suitability for poplar (Populus nigra L.), a prevalent forest species in the country, through a quantitative land evaluation method based on the FAO approach.
The research gathered and classified the edaphic and climatic requirements of poplar tree by utilizing various library resources, data from the soil laboratory of the Research Institute of Forests and Ranglands, and field survey (Soil Profiles). The climatic and soil characteristics were quantitatively classified into five categories: highly suitable (S1), moderately suitable (S2), low/critically suitable (S3), The Quantitative Classification of soil and climate properties was done in five classes: suitable (S1), moderate suitability (S2), low or critical suitability (S3), currently not suitable (N1) and permanent not suitable (N2). For validation, a quantitative assessment of land suitability for poplar cultivation was performed across six soil types, including Nowshahr forest brown, Nowshahr gray brown pedzolic rich in organic matter, Chamestan alluvial regosol, Chamestan Rendezina, Chalous  Pseudogley , and Karaj alluvial cambisol, using a parametric method (second root).
Results indicate that spruce thrives in wet and semi-humid regions in a dry-type manner, with ideal conditions found in areas receiving 1500-1800 mm of rainfall. In drier, semi-arid zones, irrigation is essential for meeting water requirements. Optimal growth temperatures for spruce range from 11-16 degrees Celsius in moderate climates. Poplar flourishes in soils with a light to medium texture, granular or cubic structure, good to fast drainage, and low underground water levels with adequate calcium and magnesium cations.
The study showed that the most suitable soils for poplars have a light to medium texture with a granular or crumb structure, with adequate drainage, the absence of high groundwater and the sufficient amount of calcium and magnesium cations in the soil. Soils with incomplete drainage and heavy texture do not provide suitable conditions for poplar plantations. In terms of quantitative evaluation, Mollic Udifluvents soils with medium texture had the highest score for poplar plantations.

Biochar, a porous carbon-rich substance, is considered a soil amendment with the ability to preserve food and water and increase drought tolerance in plants. The present study aimed to investigate the effects of biochar (derived from hornbeam wood and produced at a pyrolysis temperature of 450 °C) on the survival, growth, and physiological traits of Arizona cypress (Cupressus arizonica Green) seedlings under rainfed and irrigation conditions in a mountainous degraded forest (Do-Ab in Savadkouh region, north of Iran).

The experiment was conducted as a completely randomized design for five months during the dry months of spring and summer. The treatment combinations included: 1) control soil-irrigation, 2) control soil-rainfed, 3) soil treated with biochar-irrigation, and 4) soil treated with biochar-rainfed. Two-way analysis of variance (AOVA) was used to determine the significant effect of the treatments, and a paired t-test was used to compare the means.

The results showed that, regardless of the effect of soil treatment, irrigated seedlings had greater survival (90%) compared to rainfed seedlings (56%). However, under rainfed conditions, the survival rate in the biochar treatment was 75%, almost twice that of the control soil. In both rainfed and irrigation conditions, the seedlings grown with biochar had larger sizes than those in the control soil. Regardless of the effect of soil treatment, the rates of photosynthesis and transpiration decreased under rainfed conditions. Similar to the irrigation treatment, the biochar treatment caused an increase in gas exchanges (20-60%) compared to those in the control soil. Mesophyll conductance, relative water content, and photosynthetic pigments were higher in the irrigation treatment than in the rainfed condition.

To restore the degraded forests of the semi-arid mountainous regions of northern Iran with Arizona cypress seedlings, it is recommended that in the early years, the seedlings be managed by irrigation without applying biochar. However, under rainfed conditions, it is recommended to use biochar to enhance seedling survival and growth.

Monitoring the nutrients of tree leaves is crucial for understanding their physiological responses to environmental stresses. This study monitored the status of leaf nutrients in Persian oak trees (Quercus brantii Lindl.) affected by crown dieback during the years 2019-2021.

Two sites, one northern and one southern, were selected in the Mele-Siah area. Five healthy trees and five declining trees were identified at each site. From each tree, 20 mature and healthy leaves were collected and taken to the laboratory to measure the concentration of nitrogen, phosphorus, potassium, calcium, and magnesium elements. Leaf sampling was conducted annually in August over three years. Soil sampling was also conducted during the growing season over three years, with a hole dug on the southern side of each tree crown to measure soil moisture in two horizons.

The results showed that the amount of leaf nitrogen was highest (1.48%) in 2019 and lowest (1%) in 2020, and it was higher in healthy trees (1.30%) than in declining trees (1.22%). The amount of phosphorus was higher in the northern site in all years. The amount of potassium was highest (2.22%) in 2019 and lowest (0.58%) in 2020. The amounts of leaf calcium and magnesium were highest (1.8% and 2.36% respectively) in 2019 and lowest (0.57% and 0.69% respectively) in 2021. Furthermore, the amount of calcium was higher in the northern site (1.29%) than in the southern site (0.99%). The highest amount of calcium was found in declining trees (1.465%) in the northern site and in healthy trees (1.241%) in the southern site. The results also showed that soil moisture was higher in the northern site in all sampling years and was associated with annual changes, which affected the changes in leaf nutrients over different years.

Considering the differences in soil moisture, soil acidity, and salinity of the studied sites, as well as temporal changes in the concentration of leaf elements caused by climate changes, it can be concluded that the crown dieback of Persian oak trees is related to the physiological mechanisms involved in water and nutrient absorption.

The mechanical characteristics of roots can serve as a significant factor for selecting trees in the plantation of arid regions for soil bioengineering. This research aims to evaluate the mechanical characteristics of Tehran pine roots at various vegetative ages (one-year-old, three-year-old, and five-year-old seedlings) and under different water stress levels (light, medium, and severe) in Robat Karim. The mechanical properties of the roots were studied after estimating the water requirement of the studied seedlings at different ages for one year and based on the water stress levels. Then, five seedlings from each treatment (equal to 9 treatments) were selected and coded completely randomly to evaluate the water stress on the mechanical characteristics of the roots of Tehran pine. Initially, some root parameters such as root diameter, length of the whole root, length of thin roots, and length of the longest root were measured. Then the tensile force, tensile strength, and Young's modulus of the roots were measured and recorded using a standard Centam device. The results showed that with the increase in root diameter, the tensile force of the root changes based on the positive power relationship, and the tensile strength and Young's modulus of the root changes based on the negative power relationship. Furthermore, laboratory examinations showed that at any age, the length of the whole root and the root length densities are higher with the increase in water stress. The use of covariance analysis showed that the results of the average comparison between one-year-old age and mild drought stress, three-year-old age and moderate stress, and five-year-old age and severe stress are significant with a probability of 95%. The results of this research show that the mechanical characteristics of the root can be used as an important factor for the selection of pine seedlings in the afforestation of arid areas for soil bioengineering purposes. Therefore, it is recommended that these properties be considered in soil reinforcement modeling.

The aim of this study is to investigate the performance of various algorithms in enhancing the accuracy of land cover maps using Sentinel images.

The study area is a sheet (1:25000) encompassing an area of 15782.6 hectares. The land cover map was created using a range of algorithms - Mahalanobis distance, maximum likelihood, minimum distance, neural network, parallelepiped, support vector machine, spectral angle mapper, spectral information divergence, and binary encoding - applied to the optimal band composition derived from 12 bands (2, 3, 4, 5, 6, 7, 8, 8a, 11, 12, NDVI, SAVI). The training area was obtained from field information and satellite images. 70% of the samples were used for classification and 30% for evaluating the accuracy of the classified maps.

The results indicate that the support vector machine, neural network, and maximum likelihood classifications have the highest accuracy. The support vector machine classifier is slightly more accurate than the other two classifiers. To improve the classification, support vector machine kernels (linear, polynomial, radial basis function, and sigmoid), spectral angle mapper settings (6 modes), and parallelepiped (2 modes) were utilized. The results show that the support vector machine classifier, using the 6th degree polynomial function method, has the highest accuracy. Following this, the map was post-processed with the highest accuracy, resulting in an overall accuracy of 96.63 and a kappa coefficient of 0.9393.

An examination of 21 classification modes on Sentinel images in this study provides a comprehensive review of classification algorithms compared to previous studies.

Deadwood, at various stages of decay, serves as a diverse habitat for a wide range of species. This study investigates the diversity of macrofauna orders on fallen hornbeam deadwood with different decay classes (four classes) in district one of the Shast Kalate forest in Gorgan, Iran.

Samples were collected from 108 deadwood logs across three altitudinal ranges (200-450, 450-700, and 700-950 m a.s.l.) with three replicates for each decay class and diameter class (less than 40, 40-80, and more than 80 cm). Macrofauna were manually extracted from the deadwood and weighed to the nearest 0.001 g after identification using systematic keys. The diversity of macrofauna orders was assessed using diversity (Shannon-Wiener), evenness (Simpson), and richness (Margalef) indices.

The results revealed significant differences in mean richness, biomass diversity, and abundance of macrofauna among the different decay classes of fallen hornbeam deadwood, with higher decay intensity associated with increased macrofauna richness and diversity. The highest number of macrofauna was found in decay class four and in the 70-100 and 40-70 cm diameter classes. Macrofauna order frequency was highest in the 200-450 m altitudinal range and lowest in the 700-950 m range, with no significant difference between the first two altitudinal classes. A significant negative relationship was observed between deadwood length and macrofauna order frequency.

As altitude increased, biomass evenness increased while biomass richness decreased, suggesting that these factors counteracted each other, resulting in no significant difference in macrofauna order biomass diversity across the different altitudinal ranges.

The paper is a thin, wide sheet formed from the entanglement, flocculation, and bonding of fibers, filaments, and cellulose components. It is produced in various dimensions for numerous applications. Building on a previous study on the fluorescent staining methods of cellulose fibers, the present research investigates the microscopic structure of the sheet and its components in three dimensions (length, width, and depth) using a confocal laser scanning microscope. This study also examines the distribution of cellulose fibers and components within the paper structure's three dimensions using fluorescent properties and confocal microscopy. The cellulosic components of the paper structure exhibited a green fluorescent reflection (420-500 nm) in the visible light region when excited at a wavelength of 405 nm. Beyond the two-dimensional analysis of paper planes, the confocal laser scanning microscope provided a wide array of intriguing images, revealing how fibers or cellulose fiber fractions are distributed within the paper's thickness without the need for layer-by-layer slicing. Depth imaging of paper was successful for samples with basis weights of both 20 and 60 g/m². The resulting images showed increased flocculation and accumulation of fiber elements and segments with depth. Overall, images obtained from the confocal laser scanning microscope demonstrated that the apparatus is suitable for investigating the distribution of labeled fibers and fiber fractions in all three dimensions of the paper structure.

Different methods have been developed for the heat treatment of wood. Oil heat treatment (OHT), as a unique method, can provide a dry and oxygen-free heating medium. This study used a pilot-scale oil heat treatment to treat poplar wood at different temperatures to enhance its weathering resistance. Poplar timber was subjected to oil heat treatment using a specific heating program at three target temperatures (180, 190, and 200 °C), each held for two hours. The specimens were prepared and subjected to 1000 hours of accelerated weathering with a Gardner wheel. Water absorption and volumetric swelling were also determined during seven days of soaking in water. Contact angle measurements of water droplets, colorimetry, and ATR-FTIR analysis were also conducted before and after weathering. The dimensional stability of treated wood increased with higher processing temperature. Although the water absorption values of treated wood were lower than those of the control specimens, the difference was not significant. The samples exhibited an obvious color difference before weathering due to oil heat treatment, but their color changed to silver-gray tans after weathering. The maximum ∆E value after weathering was observed in the samples treated at 200 °C. Weathering increased the wettability of wood surfaces, but the treated samples still had a higher water droplet contact angle than those of the control sample. ATR-FTIR results determined that oil heat treatment is not an effective method for preventing the degradation of lignin in wood surface exposed to weathering factors.