فصلنامه پژوهشهای علوم و فناوری چوب و جنگل
سال سی‌ام شماره 1 (بهار 1402)

As one of the most important systems of human life, the forest has an undeniable place in ensuring the well-being and comfort of humans. Based on the forest strategy of Global Bank, it is mentioned that More than 1.6 billion People in the world depend on the forest in various ways to provide their livelihood. A common political debate about development and the environment is that the poor are both the cause and the victim of environmental destruction. The interpretation of this narrative for the forest shows it shows that the reduction of poverty can reduce the pressure on forest resources and the preservation and development of forest resources can help reduce poverty. Accordingly, in this research, the condition of the forests of Shafarood watershed in Gilan province for The implementation of two income-generating activities of apiculture and aquaculture, in order to create economic prosperity for rural communities and other beneficiaries dependent on the forests of this area, and at the same time preserving these forests based on the prioritization of criteria and sub criteria. Shafarood basin with an area of 36,657 hectares is located in the west of Gilan province, between the cities of Rezvanshahr and Pare-Sar and east of Talash highlands. In order to determine the appropriate economic use of rural communities in Shafarood forest and to identify the main criteria for each of the desired economic activities, observation, interview and questionnaire techniques were used from 55 experts which are selected randomly. In the current research, a questionnaire was used in three stages to complete the process, and the data obtained from the questionnaires related to criteria and sub-criteria were analyzed by the method of pairwise comparisons, which were use the GIS software in order to obtain the optimal spatial map of each economic activity. According to the results, in the apiculture, the criteria of plant diversity, temperature, and the number of trees per hectare, and in the aquaculture, the criteria of distance from the river, distance from the spring, and temperature were recognized as the most important factors for the development of these chains. Based on the opinion of experts for apiculture, the sub-criteria of humid climate with a final score of 0.03 had the highest score while the high investment capacity and the distance from dirt roads, both with a final score of 0.24 0 were also important. For the aquaculture, humid climate sub-criteria with a final score of 0.03 was the most important and the high investment capacity with a final score of 0.029 and a distance of less than 500 meters from the river with a final score of 0.026 were in the second and third place. The results also showed that 22.13% of the entire area (8063.31 hectares) and 14.41% of the entire area (5249.9 hectares) can be used for apiculture and aquaculture, respectively. The results can be used for economic development in Shafarood forests. According to the findings of this research in relation to the effective criteria and also the rural population present in this watershed, a relatively suitable area for each economic activity is determined. It is necessary for the forest managers to develop the rural communities based on finding the other sources of income from forest which should be paid attention to it.

The creation and construction of a forest road disturbs the natural balance of water flow in the forest area. This balance can be maintained to a large extent by installing culverts and building side channel in different traffic routes. culverts or drainage structures, as well as the road surface, often show behavior and signs before any kind of abnormality and destruction as a result of the effects of different vehicles on the road, which are related to the behavior of these signs. The ability to identify the severity of destruction and act on protection in time.

In this research, the static and dynamic anomalies of the culverts and forest road surface in different traffic levels in series one of Reyhanabad and series one of Pajim of Al-Ghadir Khalil Shahr forestry project were investigated. First, the specifications of all culverts (pipes, Made of concrete) including the thickness, diameter and length of the culvert, depth, slope and angle of its installation, the slope of the road and the flow rate of the culvert in the routes with different traffic numbers, measured with meters and inclinometers. The flow rate was calculated by measuring the cross section of the flow and the flow velocity according to the hydraulic radius, Manning's coefficient and flow slope. In the section of static anomalies, the level of health of the culvert in 4 floors was checked, as well as the unpaved road condition index (UPCI-unpaved road condition index) was measured. The dynamic abnormality includes the amount of vibration of the culvert when passing vehicles, which was calculated with the vibration meter application.

The results showed that with the increase in the installation depth of the culvert and the number of traffic, the numerical value of UPCI decreases. The lowest UPCI index values were recorded in longitudinal slopes of less than 5%. The health of the culvert increased with the increase of its installation angle. On the other hand, the lowest values of culvert health were recorded in longitudinal slopes of less than 5%. In general, the lowest level of vibration was recorded in the case of unarmored culverts that were installed at a depth of 50-100 cm, with a longitudinal slope of 5-8% and an angle of 100-120 degrees on low-traffic roads. In the routes with more than 4 vehicles per day, the vibration level of the culvert was estimated to be 2.24 Richter and in the routes with less traffic, the vibration level of the culvert was estimated to be 1.99 Richter. The reinforcement and the depth of the culvert also had a positive effect on the level of vibration of the culvert.

During road construction, observe points such as loading capacity, timely stabilization of the road, taking into account the shear position, timely compaction as well as implementing consolidation operations, taking into account hydrological properties (number of culvert crossings, water flow rate, transverse slope and moisture regime), creating ponds, applying operations. A course in road maintenance (current and periodic) on a continuous basis in forest roads, compliance with depth, reinforcement, longitudinal slope of the road, angle of installation relative to the axis of the road and taking into account the number of traffic in the design of the culvert It is necessary and can be effective in its health, vibration and efficiency.Key words: Unpaved road condition index, Gravel road, Forest road, Tubing.

One of the oldest methods of classification and identification of different plant species is the use of morphological traits. Among the morphological characteristics, leaves are very important due to photosynthesis and carbon capture. Morphometric analysis is usually done by two traditional and geometric methods. The studies of the morphological changes of plants in Iran are based on the traditional method and geometric morphometry has been used for animal species. The aim of this study is to investigate the changes in the geometrical morphology of Fagus orientalis leaf at different altitudes and to compare its results with the traditional morphological changes.

In this research, the natural population of Fagus orientalis was sampled in four altitudinal stations. In traditional morphological method, 40 trees were selected and in geometric morphology, 10 trees were selected at each height, and 1 leaf was selected from each direction of the tree crown. In the traditional study, morphological traits including lamina length, lamina width, lamina area, lamina perimeter, Shape factor and Length to width ratio measured with a Leaf Area Meter device. In the geometrical study, the sample of collected leaves was dried and then stored digitally with a scanner in the form of an image and the 8 morphological traits that are scanned as landmarks on the images are supposed to be used to investigate the morphological changes of eastern beech leaves at different altitudes. Data analysis was done with multiway analysis of variance and Duncan's test.

The results showed that altitude is one of the important factors in the formation of leaf morphology in eastern beech. Trees that grow at high altitudes generally have smaller leaves which showes the adaptability of the eastern beech to the environmental conditions at each height level. The characteristics of the beginning of the petiole, the end of the petiole, the last vein on the left side, the widest leaf width from the left side, the widest leaf width from the right side in geometric morphology and the characteristics of the perimeter and area in traditional morphology were introduced as the most effective traits in the separation of populations.

In this study, it was found that the populations of different altitudes were separated in both traditional and geometric morphological methods, and it was shown that the two traditional and geometric methods do not work in the same way between samples, the grouping of most populations in morphological Geometrical analysis shows the efficiency and accuracy of this method in the separation of populations. Using this modern method, geometric information about morphological differences can be displayed in images and using different images. As a result, the differences in the populations are highlighted and the interpretability of the results increase. Detetmining the most effective traits in the separation of populations also indicats that the capability of the geometric method is more different and more detailed in defining traits.

The investigation of chemical, physical and biological soil properties in developmental stages could be an appropriate approach in low-altitude forest management concerning these ecological services. Investigating the changes in soil properties during the developmental stages of the low-altitude forest is of great importance in improving the ecological services. This research aimed to investigate the effect of different developmental stages of the mixed hornbeam stands on some physical, chemical and biological properties of soil in two seasons, autumn and summer (with a time interval of one year) in series number two of forestry plan of Shastkalateh, Gorgan.

35 half-hectare rectangular sample plots with dimensions of 50 x 100 meters were considered to identify the different developmental stages after the field visit. In each of the samples, the type of tree species, shrubs and the diameter at breast height were measured. Finally, using Feldman et al. (2018) index, three developmental stages of initial, optimal, and decay were determined for all samples and three replicates were considered for each stage. In each of these nine main sample plots of half a hectare, five micro-samples of 20 x 20 meters were selected; one of them in the centre and four others in the corners, then soil samples were taken from a depth of 0-15 cm in each micro-sample at summer and autumn. A total of 270 soil samples were analyzed.

The results of this study showed that there is no significant difference in the physical properties of the soil including sand, clay, silt and bulk density in the different developmental stages in the two seasons autumn and summer. But in both seasons, the soil moisture in the optimal stage was significantly higher than in other stages. Examining the chemical and biological properties of the soil showed that electrical conductivity, organic carbon, and the ratio of carbon to nitrogen, ammonium, and nitrate of the soil had significant differences between different developmental stages in the autumn. In the summer, acidity, electrical conductivity, percentage of organic carbon, total nitrogen, and microbial biomass of carbon, ammonium, and nitrate had significant differences between different developmental stages. The results of principal component analysis using the studied variables showed that, in general, the first and second main components accounted for 39.16 and 15.11 percent of the total changes, respectively. The acidity, electrical conductivity, and percentage of organic carbon, ammonium and nitrate had a high correlation with the first axis. Soil moisture, ammonium and nitrate had a positive correlation with microbial carbon biomass. While the variables of acidity, electrical conductivity and percentage of organic carbon had a negative correlation with microbial carbon biomass. Ammonium and nitrate also had a negative correlation with acidity, and electrical conductivity and organic carbon percentage showed a positive correlation with soil moisture.

Based on the results of the present study, it can be stated that in the low-altitude forest of the mixed hornbeam stand, the development stages had a significant effect on the chemical and biological characteristics of the forest soil. Although in other studies the significant effect of developmental stages on the physical properties of the soil has been reported, in the present study, the developmental stages had no significant effect on the physical properties of the soil. The results of this research contain valuable information about the seasonal dynamics of the soil characteristics of the low-altitude Hyrcanian forests in different developmental stages, which shows the relationship between the forest stands and the changes in soil characteristics over time.

Accurate in situ measurement of DBH is easy and cost-effective but, height measurement is labor-intensive, time-consuming and expensive. Understanding its height–diameter relationship is essential for developing growth, biomass production and carbon storage prediction models to be applied in the current forest management projects. The existence of a strong relationship between the diameter and the height of trees is considered as a useful index in forest management and it can be described with mathematical models. Considering that non-linear models are flexible, interpretable and strong, therefore some of the most important models were used in this study.

In this research, 21 widely used candidate nonlinear and one simple linear models were fitted to tree height and diameter at breast height (DBH) data for Populus euphratica Oliv. within a 100 square meter plots at Shoosh area of Khuzestan province. Data from 1163 trees were used and split randomly into two sets: 80 % of the data were used to estimate model parameters (model fitting), and the remaining data (20 %) were reserved for model validation. All model performances were evaluated and compared by means of model performance criteria such as t-statistics of model parameters, root mean square error percentage (RMSE%), mean absolute error percentage (MAE%), mean bias error percentage (ME%), Akaike’s information criterion (AIC) and Bayesian information criterion (BIC).

The parameters of 8 models were not significant at a level of 5%. RMSE, MAE, Bias, AIC and BIC values for M12 model were obtained: 8.98%, 6.78%, -0.0010%, 1451.82 and 1469.73, respectively. The same values were obtained for M21 model: 9.15%, 6.94%, 0.0005%, 1476.95 and 1494.86 respectively. The predicted and actual height values in these two models were not significantly different at a level of 5%. The results of the paired sample t test showed that the nonlinear models M21 and M12 have predicted the height of Populus euophratica trees with appropriate accuracy. Two models (Prodan1 with the name of M12) and (Prodan2 with the name of M21) were selected as the best models based on the ranking of all model performance evaluation criteria in fit and validity data.

The majority of two-parameter models and some three-parameter models showed a significant fit with the data. However, in terms of all performance evaluation criteria, two three-parameter models were chosen as the best models. According to the results of this study and the wide range of non-linear two and three parameter models, mixed models that include one or two covariates in the modeling in addition to the main variables, more research is needed in larger geographical areas, wider sites and stands with different structures are done.

Afforestation with oak (Quercus brantii Lindl) trees has been done for restoration of degraded areas in Zagros forests, however, few studies have been done on the dynamics of leaf and soil nutrients compared to natural trees (standard and coppice). The aim of this research is to compare the nutritional elements of leaves in natural trees (standard and coppice) and planted forms of persian oak (with an average age of about 30 years).

According to the objectives of the research, in the city of Ilam, where afforestation with persian oak species was carried out in the vicinity of its natural form, sampling were done from leaves and the soil (at a depth of 0-20 cm) in the two seasons of spring (April) and summer (September) to compare the changes in carbon, nitrogen, phosphorus, potassium, calcium and magnesium and some physical and chemical characteristics of the soil. Two-way analysis of variance (GLM) used to compare the soil and leaf properties among different regions. Principal component analysis (PCA) and Pearson's correlation test were used in order to investigate the relationships between leaf and soil nutrients and their changes in different forms.

results of GLM showed that nitrogen and phosphorus of leaves were affected by different forms of oak species and season, and their amount is higher in spring than in summer. So that the amount of nitrogen in the leaves of standard (20.2% to 1.68%) and planted trees (1.78% to 1.25%) was higher in spring compared to summer. The amount of calcium in the leaves in summer was between 1.5 and 2 times higher than in spring (planted oak; 303.66 ppm to 170.33 ppm, coppice; 282.33 ppm to 149.33 ppm, standard tress, 285.66 to 233 mg/kg. Leaf potassium was influenced by different oak forms and seasons. So that it was more in spring than in summer and in standard (201.16 mg/kg) and planted trees (161.47 mg/kg) it was 1 to 1.5 times than that of coppice trees (128.30 mg/kg). Principal component analysis and Pearson correlation showed that in two seasons, different forms of oak can be separated from each other.

Therefore, it can be said that the planted Persian oak trees are similar to the standard form in terms of nitrogen, potassium, and phosphorus elements and were more than coppice trees. In addition, in planted, unlike natural forms, the amount of leaf elements were higher in summer than in spring.

Vegetation is one of the main components of the biosphere and a vital element in the climate system, and knowing its changes and activity trends can affect the optimal productivity of agricultural land, natural ecosystems, climate change, and biodiversity. Vegetation indices derived from satellite data have provided a powerful tool for monitoring and investigating vegetation dynamics in large temporal and spatial scales. The aim of this study is to investigate the long-term trend of vegetation in pixels to pixels in Mazandaran province using the NDVI time series of MODIS sensor.

The current research was conducted in the province of Mazandaran, which includes 53% of Hyrcanian forests and 12050 square kilometers of rangeland. In this study, the vegetation index products of the MODIS sensor with a spatial resolution of 250 meters and an interval of 16 days, named MOD13Q1 and MYD13Q1, have been used. The NDVI index images available in these two products were combined and a time series of 828 images with an 8-day interval and a spatial resolution of 250 meters was created from the NDVI index for the period from 2003 to 2021.In order to increase the quality of the time series, the pixels affected by clouds, snow and ice in each image of the time series based on MODIS quality assurance information and the seasonal component within the time series that may make long-term trend investigation difficult, using the Anomaly method were removed. Then the time series was analyzed using parametric ordinary least squares (OLS) regression and non-parametric Theil-Sen and Mann-Kendall in Google Earth Engine (GEE).

The results of this study showed that the output of OLS, Theil-Sen and Mann-Kendall methods were close to each other and Greening and Browning occurred in about 87% and 13% of the province, respectively. Also, the significance of Man-Kendall trends shows that 77.21% of trends in the province, include 70.65% of positive trends (Greening) and 6.56% of negative trends (Browning) at ρ < 0.01, 6.48% and 2.95% of trends at ρ < 0.05 and ρ < 0.10 are significant, respectively. The spatial distribution of the trends also showed that a large part of the Browning trends occurred in the plains of the north of the province and most of the Greening trends occurred in forest lands and rangeland.

In general, this study showed that greening occurred on a large scale, especially in natural vegetation including forests and rangeland. Changes in natural vegetation are affected by climate change, because human activities are limited in them. Therefore, the process of global warming can be the most important factor of Greening in Mazandaran province.

Mangroves are one of the most important and effective cover of mandabi ecosystems, which are evergreen and resistant to salinity and grow in the coastal areas of tropical and subtropical regions, so that they can adapt to the conditions like high salinity, wind, anaerobic soil environment and tides with high height. Despite the many environmental services, these forests are considered as threatened ecosystems in tropical and subtropical regions, which are very vulnerable to human activities and climate changes and are exposed to a threat. During the recent centuries, the destruction of mangrove habitats as a result of coastal development, pollution, aquaculture, logging and exploitation and fuel supply has been done more intensively and has led to a drastic reduction in the area of the mangrove ecosystem. One of the most important human threats in the mangrove forests of Hormozgan province is especially the cutting of mangroves by local people in order to raise livestock. The percentage of importance of cutting in Hormozgan is much higher than other threats, so the purpose of this research is to investigate the effect of different intensities of cutting on the reproductive and growth characteristics of forest stand.

The location of the project was (an area 180 meters long along the coast and the length of the mangrove forest, along the highest and lowest tide levels). This design was carried out in a completely randomized design with 4 treatments and 10 replications in plots 40 meters long and 25 meters wide along the slope of coastal lands. In each plot along its diameter, 10 mangrove trees whose crown diameter was more than 2 meters were selected and cutting treatments with percentages (zero, 10, 20 and 30%) were implemented on the sample trees (40 sample trees). It is worth mentioning that the diameter at a height of 30 cm and the height of the sample trees, the reproduction status around the sample trees, the diameter and height of the surrounding trees, the sample trees before cutting and 5 years after cutting were measured and it was compared using one-way analysis of variance.

The results showed that the height and diameter growth rate of the sample trees was the highest in the control treatment with values of 0.45 meters and 2.37 centimeters, and significantly more than the 20% treatment (0.23 meters and 0.94 cm) and 30% treatment (0.17 meters and 0.52 cm). Also, the reproduction rate around the sample trees was significantly reduced by cutting. The reproduction rate was the highest in the control treatment with 0.093 seedlings per square meter, while the lowest value (0.031 seedlings per square meter) was observed in the 30% cutting treatment. It is worth mentioning that 10, 20 and 30% cutting was observed in the control treatments, respectively, with the number of 0, 3, 5 and 8 diebacked seedlings≤ 5 cm, during 5 years. In examining the effect of cutting on the growth of trees around the sample tree, no significant effect was observed.

Overall, the results of this research showed that grey mangrove trees are very sensitive to human intervention and cutting and react strongly. This reaction was shown in the field of the habitat in the form of a decrease in vegetative characteristics and seedling production around the cut trees.