مجله پژوهش و توسعه جنگل
سال هفتم شماره 3 (پاییز 1400)

In recent years, the general policy of the country has been based on the decision to stop the exploitation of wood from the north industrial forests. While the population is increasing, the demand for wood is increasing. Therefore, it’s necessary to find alternative sources to supply raw materials for the wood industry. In Iran, every year, a lot of wood waste is burned and wasted due to a lack of development and promotion of appropriate exploitation methods. In present study has been investigated the exploitation and optimal allocation of wood residues from pruning apple trees as raw material for the particleboard industry. Exploitation was carried out in apple orchards of Damavand city with a chipper and transported to factories by truck. Evaluations of the work process and the productivity and cost have been done with continuous timing method and optimal allocation have been made with the linear programming model by transportation method and simplex algorithm. The results showed that the longest recovery time of residues is related to the collection and transfer to the depot and chipping them, respectively and the production of residues is 1.97 tons per hectare and the production of chips is 0.160 tons per hour. Also, the optimal allocation of 400,000 tons of resources from the exploitation of pruning residues of apple trees with a minimum cost of transportation (950 billion rials), while solving the problem of waste disposal and reducing environmental pollution will bring an annual profit of about 450 billion rials for the country and will be compensated part of the shortage of raw materials for the particleboard industry.

The impact of logging and tree harvesting on the ecological function and the future of Hyrcanian forests structure is a continuing debate topic. The information is currently available does not support firm conclusions about the impact of forest harvest intensity on forest structure and biomass. The present study aims to evaluate the effect of single-tree selection harvest intensity on biomass of hornbeam-Persian ironwood stand. For this purpose, information on all trees and dead trees were collected in 70 half-hectare plots. The 35 sample plots were in single-tree selection stands with three harvest intensities and the same sample plots were in control stand. Trees litter fall were measures from September to February and the storage of soil organic carbon was determined through organic carbon and bulk density. Then, tree biomass, litter biomass, dead tree biomass and total biomass were finally calculated. The results showed with increasing the rate of harvest intensity up to 13.5% the total biomass had rising trends, although harvest intensity had no significant effect on aboveground and belowground biomass and soil organic carbon. The aboveground biomass was higher in single-tree selection stand than control stand. The average of total biomass was 147 and 144 ton/ha in harvest and control hornbeam-Persian ironwood stands respectively and harvesting increased two percent of mean total biomass. The medium harvest intensity (3.6-9.5% of stand volume) was finally determined as appropriate selective logging intensity. The correspondence of litter biomass and dead tree biomass as bio indicator indicated that tree marking in the single-tree selection system was advisable.

In order to introduce and application of DEI (Distance of Edge Influence) and MEI (Magnitude of Edge Influence) indices to determine the distance of edge effect and intensity of the edge effect on herbaceous species and soil chemical properties, Three forest fragments (under 10 hectares) from oak forests of Kermanshah province were selected with similar conditions in terms of slope, direction and altitude. In each fragment three transects were established from the edge to the forest interior. Measurements of vegetation and soil variables were collected at 0 (edge), 25, 50, 100, 150 m along each transect. The results showed that MEI index values ​​were positive for soil variables (except nitrogen, organic carbon and pH). The values ​​of this index were also positive for species richness, Shannon-Wiener diversity and Evenness. DEI index value ​​was 25 m for soil variables except pH and 50 m for diversity indices. The influence of edge on species richness, Shannon-Wiener diversity and Evenness was significant. Soil variables (except phosphorus) did not show significant differences at different distances from edge. Also, changes in species richness and soil chemical properties were observed in 0-50 m from edge. Totally, in sparse oak forests, fragmentation and edge effect had influence on species richness and soil chemical properties.

The aim of this study was to determine and compare the genetic diversity of wild populations of Thuja orientalis by biochemical markers polymorphism of leaves and two-year-old branches Peroxidase. The sampling was done in 30 individuals of Thuja orientalis in three populations. Samples were taken from medium crown height in the south direction. Data analysis was performed by GenAlEx software on the allele characteristics of the studied markers and comparing the ability of these two organs and grouping of the trees to examine the intra- and inter-population variation by cluster analysis of electrophoretic data (prepared gels) by NTSYS 2.02 software. Qualitative measures was studied by vertical electrophoresis and PAGE (polyacrylamide gel electrophoresis) method and the electrophoretic data were classified using cluster analysis. According to the results, the second population with the average number of alleles observed per gene locus (2), the average effective number of alleles (1.77), the expected heterozygosity (0.42), and the percentage of polymorphism (100) have the most allelic separation indices in comparison to the other two populations. Also, the higher genetic diversity in intra- population (nearly 60) than inter-populations (nearly 40) should be considered in the management of this reserved forest to increase diversity. Also, the scale in Thuja sp. with the average number of alleles observed per gene locus (1/48), the average effective number of alleles (1.49), the expected heterozygosity (0.27), mean Shannon's information index (0.39), number of bands (9) and percentage of polymorphism (66/67) has better allelic characteristics than the branch in genetic diversity studies.

Mosses are small, non-vascular and non-flowering plants. Forsstroemia remotifolia was previously belonging to Leskeaceae family and its old name is Pseudoleskeella laxiramea (Schiffn.) Broth. According to recent morphological researches, changed from Leskeaceae family to the Neckeraceae family. Therefore, in present study, to eliminate the ambiguities in classification of this species, phytochemical and palynological investigation in F. remotifolia, Homalia besseri, and P. catenulata seems necessary. The results of gas chromatography (GC/MS) are showed that, F. remotifolia has 21 different types of fatty acids, H. besseri contains 23 types and P. catenulata possesses 18 types. Analysis of fatty acids has been shown 61.53% similarity in fatty acid compounds between F. remotifolia, and P. catenulata. Results of palynology showed that spore shape in populations of F. remotifolia is spheroidal and spore shape in populations of H. besseri is oblate, but the spore shape in population of H. b. A belonging to H. besseri is prolate and also the spore shape in population of P. c. Do. belonging to P. catenulata is spheroidal. Overall results of chemotaxonomy and palynology indicate close relationship between F. remotifolia, and P. catenulata.

The main purpose of this study is determination of optimal wood distribution and transportation Network in Iran with emphasis on railways. For this purpose, a simple distribution and transportation model was created for seven groups of wood in GAMS 24.1.3 software. This transportation model is simple, the planning horizon is one year and the transportation method is both road and road-rail. The results showed that after optimization, in the road-rail method, 6.86% of total wood will be transported by rail network and 93.14% will be transported by road network. This method reduces the total cost of transportation by 24.02% compared to the actual conditions in the road transport method. In the road method, after optimization, the total cost is reduced by 22.31%. This cost reduction in both methods is related to the optimal distribution of wood from the distribution bases to the receiving bases and the appropriate selection of the cargo fleet based on the tonnage of the load and the radius of shipment. In the optimal transportation distance in the road-rail method 45.36% and in the road method 43.42% and the number of loads respectively 34.77 and 29.04% compared to the conditions Non-optimal will be reduced. Given the high rate of wood consumption in Iran and the importance of improving productivity indicators in the field of freight costs as one of the strategic goals of the transportation sector in the coming years, the need to recognize and create a chain of distribution and optimal transportation of wood is remarkable.

The aim of this study was to investigate the accuracy and precision of single microplot method in estimating the regeneration of wild cherry and introducing an alternative method. For this purpose, after a primary survey, three parcels in district-7 from Shafarood basin, which had mother trees and wild cherry regeneration, were selected. A total of fifty circular plots were taken randomly, in a 150×200 m grid, each 1000 m2 area. Four microplots were measured at a radius of 2 m and all the cherry seedlings were counted. A transect, 0.2 m wide and 10 m long was layed in each plot and all of the cherry seedlings under 1.3 m height were counted. In an area of 10,000 m2, including 10 randomly selected plots, all wild cherry seedlings were counted and calculated density was considered as control. Based on the results, the sampling error in the clustered-microplot method was minimal (18.69%) and in the transect method was maximum (45.62%). In terms of the accuracy, the clustered-microplot method had the highest accuracy (15.72%) and transect method had the least accuracy (111.74%) in density estimates. One-sample t-test showed that there is a significant difference between transect and single-microplot methods with the control in 5% confidence level, while the clustered-microplot was not statistically different. It can be said that the clustered-microplot method is more superior than single-miroplot method and is preferable for accurate and precise estimation of regeneration for rare specieses like wild cherry.

Since the beginning of creation, man's relationship with the forest has led to the formation of traditional knowledge, which has been mainly aimed at meeting human needs. Ethnobotany is the study of a region's plants through the traditional knowledge of a local culture and people. One of its important branches is related to the medicinal values of plants. Due to the existence of different local communities in the Zagros region and the diversity of traditional knowledge in this area, as well as the lack of information in this field, the study tried to study traditional knowledge related to medicinal properties of plants in the common-law forest area of Chenarkol in Khorramabad city, Lorestan province. Based on the results, 44 woody and herbaceous medicinal and edible (mainly fruit of trees and shrubs) species were identified in the area and their traditional knowledge especially their application and the way of preparation was recorded. Among the plant organs used, fruits and leaves had the largest share with 27% and 23.5%, respectively. Twenty species had only edible use, while only medicinal plants had nine species. Twenty-four species (54.5%) of the plants were used raw, most of which were either edible forest fruits (such as Pistachia atlantica and P. khinjuk) or as a vegetable (such as Nasturtium officinale and Adiantum capillus-veneris). The findings confirm that local communities in the area are well acquainted with the region's native medicinal plants and their medicinal and nutritional values, but combining the rich traditional knowledge of the villagers and nomads with the basics of conservation and sustaining the ecosystem is an issue that needs serious attention.

Changes in flooding regime have resulted in widespread declines in ecosystem functioning Flooding affects soils by altering soil structure, depleting O2, accumulating CO2, inducing anaerobic condition in soil, development of root rot, loss of mycorrhizae, and reductions in root metabolism, leads anaerobic decomposition of organic matter, and changing macro and micro elements of soil and leaf. In this experiment, the variations of macro and micro nutrient concentration in soil and leaf of Alnus subcordata (L.) seedlings under soil flooding stress were investigated during a 120-day outdoor experiment. Seedlings were subjected to three fixed treatments: 1) unflooded; 2) flooded to 3 cm depth and 3) flooded to 15 cm depth and their macro and micro nutrient concentration in leaf and soil were measured at the end of the experiment. Results indicated flooding had no effect on the concentration of Mg, Ca, Zn and organic C soil, while the concentration of P, N and K decreased and the concentration of Fe and Mn increased in the soil by flooding, although did not result in toxicity of elements of soil. In leaves of flooded seedlings, the concentrations of N, P, K, Zn, Ca, Mg and organic C decreased, but the concentrations of Mn and Fe increased to a detrimental level. In addition, there was a significant positive correlation between most of elements in soil and leaf. Generally, the results indicated that flooding changed the concentration of much elements in leaf and soil seedlings of A. subcordata that it is a current phenomenon in anaerobic condition of soil caused by flooding.

Altitudinal gradient is effective on biodiversity indices. Tiremrud Basin (Watershed 32) were investigated to find the relationship of plant biodiversity indices. Data were collected by transect method with at least one sample plot per align lines with 50 m interval and 44 plots in total. In each sample plot the total number of tree species was recorded. Micro plots (5*2 m2) in four corners and center of each plot were determined and recorded based on the Brown-Blanket cover percentage and frequency of vegetative elements for sampling of herbs. Bilateral index species analysis was used to introduce the communities of the region. The results showed that the four ecological groups of the region had an average altitude of 2070, 1236, 924 and 375 meters above sea level and an average slope of 43, 50, 40 and 59 percent (no significant difference). Comparison of ecological groups showed that these groups have significant differences in terms of plant biodiversity indicators. Examination of Shannon-Wiener and Simpson-Pilo species diversity index values ​​showed that the first, fourth and two second and third ecological groups have maximum, minimum and average values ​​of species diversity indices, respectively. Meanwhile, in terms of Pilo uniformity index, the first and third groups, along with the second and fourth groups, have the maximum, minimum and average uniformity index values, respectively. In terms of species richness index, the first, third, second and fourth groups are ranked respectively.   Altitudinal gradient is effective on biodiversity indices. Tiremrud Basin (Watershed 32) were investigated to find the relationship of plant biodiversity indices. Data were collected by transect method with at least one sample plot per align lines with 50 m interval and 44 plots in total. In each sample plot the total number of tree species was recorded. Micro plots (5*2 m2) in four corners and center of each plot were determined and recorded based on the Brown-Blanket cover percentage and frequency of vegetative elements for sampling of herbs. Bilateral index species analysis was used to introduce the communities of the region. The results showed that the four ecological groups of the region had an average altitude of 2070, 1236, 924 and 375 meters above sea level and an average slope of 43, 50, 40 and 59 percent (no significant difference). Comparison of ecological groups showed that these groups have significant differences in terms of plant biodiversity indicators. Examination of Shannon-Wiener and Simpson-Pilo species diversity index values ​​showed that the first, fourth and two second and third ecological groups have maximum, minimum and average values ​​of species diversity indices, respectively. Meanwhile, in terms of Pilo uniformity index, the first and third groups, along with the second and fourth groups, have the maximum, minimum and average uniformity index values, respectively. In terms of species richness index, the first, third, second and fourth groups are ranked respectively.

To investigate the effect of recreation on plant species diversity and edaphic characteristics, this study was done in Gamboueh Forest Park of Ahvaz with an area of 60 hectares in 1398. For this study, sampling method was used using a linear transect with a length of 300 meters and sampling parts were randomly used at 50-meter intervals. In order to study the tree and shrub cover in two recreational and non-recreational areas, 24 sample plots of 20×20 m (400 m2) were placed and in the center of each plot, in order to study the grass cover, the sample plots of 8×8 m (64 m2) were implemented. In this study, 28 plant species were identified. Conventional comparative analysis (CCA) showed that the control area and the recreation area each formed a separate ecological group in the area. In terms of plant species composition, the highest values of Simpson species diversity indices (0.33±0.023), Shannon-Wiener (0.44 ±0.012) and Shannon-Wiener uniformity index (0.6±0.003) And plant species richness (2.9±0.61) was estimated in the control area. Examination of edaphic conditions showed that recreation could not have an effect on soil texture, but characteristics such as porosity, nitrogen, potassium, phosphorus and organic matter decreased under the influence of recreation and characteristics of bulk density, saturated moisture, electrical conductivity and lime increased significantly. The results of this study indicate that recreation without observing technical and scientific criteria can reduce the density and diversity of grassland vegetation in the region, which can have destructive effects on habitat.