Assesing the capability of polymer stabilizer in forest road stabilization (Case study: Kheyrud forest)
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article
2014
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Some soils cause many problems to the road because of their undesirable mechanical properties. Several methods have been proposed for improving the mechanical properties of soil and in this study the ability of a polymeric was tested. As the soil of study area is fine-grained texture, with high clay content and plasticity, it's necessary to improve the mechanical properties and stabilize the soil before road construction. Therefore, various laboratory tests including grain size distribution, Atterberg limits, soil compaction and California Bearing Ratio (CBR) were performed on control and treated samples. The results showed that the material decreased the liquid limit and plasticity index and increased the optimum moisture, maximum dry density and bearing capacity. However, the improvements in soil properties, especially increasing the bearing capacity, were not as high as claimed by producer company.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
1
10
https://www.ijf-isaforestry.ir/article_6046_63b2874e9f66b5659b37f1c0c1486ffd.pdf
Comparison of non-linear height and diameter functions for oriental beech (Fagus orientalis Lipsky.) in a mixed and uneven-aged Caspian forest (Case Study: Tarbiat Modares University forest research station)
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article
2014
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Height - diameter equations are often used to estimate tree height, when tree diameter is the only measured variable. Considering that tree diameter measuring is often easier and inexpensive than tree height, height-diameter functions are generally used to estimate tree height. In this study, nineteen non-linear height-diameter equations were fitted using data of Fagus orientalis Lipsky in the Experimental and Educational Forest of Tarbiat Modares University. The data were split into two groups: 315 individual trees for model calibration and 290 for validation. Root Mean Square Error, adjusted R2, Akaike Information Criterion and Mean Difference criteria, as well as biological evaluation were applied to select the most appropriate model. Moreover, validation datasets were divided into 5-cm DBH classes and Mean Difference was computed for each model in each class. The results showed that the used models could explain a variation amount of 0.70 – 0.76. Weibull, Schnute, and Richards appeared to be suitable models with regard to mathematical and biological features. We recommend the Richards model as the best model to predict beech height trees for its better performance than the others in the Experimental and Educational Forest of Tarbiat Modares University.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
11
22
https://www.ijf-isaforestry.ir/article_6047_84175f4811a657859dc3384d30bae60d.pdf
Changes of macro and micro elements concentration in shoots and soil of Quercus castaneifolia seedling grown in flooding conditions
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article
2014
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The aim of this study was to investigate the variation in concentration of macro- and micro- nutrients in soil and shoots of Quercus castaneifolia seedlings growing in flooded and non-flooded conditions. For this purpose, one-year old seedlings of this species were subjected for 120 days to three different conditions: (i) well-drained control (ii) permanent flooding and (iii) periodic flooding in an experiment as a completely randomized design. The results showed that flooding reduced the ratio of Organic carbon, Total Nitrogen and available Potassium in the soil. Potassium concentration in permanent flooding was reduced to 49% in comparison to control treatment. Also, in the permanent flooding, availability of Fe and Mn increased to 42% and 51% with respect to controls, respectively. Under flooding conditions, nutrient accumulation decreased in leaves of stressed seedlings. In addition, the reduction in N, Ca and Mg in permanently flooded seedlings was greater than those in seedlings growing under periodic flooding. The Zn concentration in leaves diminished as a result of the permanent flooding. In both flooding regimes, Mn concentration in leaves with respect to controls increased 2.5 times, whereas Fe concentration increased 2.5 and 3.5 times, respectively. There was found a positive significant correlation between most of nutrient concentrations of soil and leaf. In conclusion, macro-nutrients in soil and shoot of seedlings under flooding stress were reduced whereas micro-nutrients increased. Taking into account that some macro-nutrient concentrations in soil and leaf of seedlings grown in periodic flooding were greater than those in permanent flooding, it is concluded that for growth of Q. castaneifolia seedlings, periodic flooding is more favorable environment than permanent flooding.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
23
34
https://www.ijf-isaforestry.ir/article_6048_f6cea0a0a4fe1f032eb276be0681c650.pdf
The relationship between fuel moisture content and leaf spectral reflectance of Quercus brantii in Chahartagh Reserve forest, Chaharmahal Va Bakhtiari province
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article
2014
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To assess the physiological states, the stress impact and ultimately the overall health condition of living plants, measuring moisture content is a well-known choice. Alteration in plant water is more likely occurs not only after prolonged drought and fire prone forests, but also in more sparse and weaken stands. Hyperspectral remote sensing techniques try to provide means to quantify the leaf moisture content with low cost, high-speed, online and up-to-date information. In this study the relationship between spectral reflectance of Quercus brantii leaves and fuel moisture content, equivalent water thickness and specific leaf weight was estimated. The sampling was done on 40 randomly selected oak trees in southern and western aspects in central Zagros range. To acquire spectral reflectance the leaves were scanned through wavelengths 350 to 2500 nm, using a ASD Fieldspec® field spectrometer. For each tree, leaves were picked up from four canopy directions. Then the leaf wet and dry weights as well as their masses were determined. Water Index (WI) spectral was most significantly correlated to fuel moisture content (P<0/001, r=0/22). In addition, WI and Normalized Difference Vegetation Index (NDVI) showed high correlation coefficient with both fuel moisture content and specific leaf weight. None of the spectral indices could establish significant relationship with equivalent water thickness. On the other hand, there was also no significant difference between fuel moisture content, water equivalent thicknesses, and specific leaf weight with spectral indices in four of the tree crown direction. Nevertheless, there was significant difference between leaf equivalent water thickness and indices NDVI, NDSI [1108, 1242] and NDSI [1108, 1457] in both western and southern aspects.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
35
48
https://www.ijf-isaforestry.ir/article_6049_e9066cf61a048794698c016c8c745c67.pdf
Investigating the amount of reinforcement of Alnus subcordata root in order to use in bioengineering
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article
2014
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The root of vegetation is known to increase the hill-slope stability by reinforcing soil shear strength. The amount of reinforcement depends on density and tensile strength of roots therefore this study assessed these biotechnical properties. The profile trenching methods was used to obtain root area ratio (RAR) and number and diameter of roots in each depth were measured. Standard Insrton was used to determine the tensile strength of roots. The results indicated that the root density and number of root were decreased with increasing depth. Tensile strength is decreased with diameter of roots following power function with an average of 16.29 MPa. Using the results of biotechnical characteristics and Wu model, the reinforcement effect was calculated and minimum and maximum of reinforcement were 0.55 KPa and 110.76 KPa, respectively. The results presented in this paper can be used for hill-slope stability with bioengineering method.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
49
58
https://www.ijf-isaforestry.ir/article_6050_2f1d78d75cb43c6e8a36a72980ca5a80.pdf
Separation of Brant`s oak (Quercus brantii) populations using macro-morphologic leaf indices
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article
2014
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Leaf samples were collected from 37 populations of Brant`s oak (Quercus brantii) high forests across Zagros in five provinces of Iran. The samples were subsequently labeled based on their maternal trees’ communities and populations, and the crown position, which leaves were located. For each leaf, lamina length to width and lamina to petiole length ratios as well as the number of veins and marginal teeth, a new invented leaf index called “serration index” and the angle between the outmost marginal tooth direction and leaf blade edge were measured. A fully nested ANOVA analysis showed that a steady pattern of decline exists in all leaf indices from community (high differences) to crown position (no difference). Sharp differences detected based on the leaf indices related to marginal teeth and veins. Using the leaf indices following clustering the populations, the results showed an up to 50% variation between southern and northern Brant`s oak populations. Considering two factors of heritability and phenotypic plasticity through proper research methodology, the results suggest a revising in botanical classification of the Brant`s oak taxa based on the samples collected in agreement with latitude as well as altitude alterations.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
59
74
https://www.ijf-isaforestry.ir/article_6051_78212ef5a5680e4832d7613b7676b2f2.pdf
Variations of understory vegetation composition and diversity in pure and mixed beech stands (Case Study: Kheyrud Forest- Noshahr)
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article
2014
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This study aims at comparing the understory vegetation composition and diversity in pure and mixed beech stands in the Hyrcanian forests. Nine pure beech and 15 mixed beech stands were selected. In each stand, 400 square meter (20×20 m) sample plots were established to determine the cover and abundance of all understory plants using Braun-Blanquet scale. As a biotic environmental parameter, beech tree-layer proportion of each sample plot was determined. At the center of each releve, two soil samples were taken from 0-10 and10-30 cm depths to analyze pH, organic matter, lime, available phosphorous, total nitrogen and exchangeable potassium. For measuring plant diversity within each sample,species richness, Evenness, Shannon and Simpson diversity indices were calculated. Non-metric multidimensional scaling (NMS) was applied to assess the rate and direction of changes on the understory vegetation in the different stands and t-test was used to test the differences in the species diversity indices between pure and mixed beech stands. The NMS result showed that the understory vegetation differed in pure and mixed beech stands and were categorized in distinct groups. The main variation gradient was firstly associated with beech proportion in the tree layer and then related to organic matter and total nitrogen in the first soil depth. All diversity indices and understory species frequency were higher in mixed beech stands than pure ones. Frequency of many species such as Carex divulsa,Calystegia sylvestris and Brachypodium sylvaticum decreased while increasing the proportion of beech in the tree layer. However, shade tolerant species such as Cardamine bulbifera and Mercurialis perennis were observed with higher frequency in pure beech stands than mixed ones.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
75
86
https://www.ijf-isaforestry.ir/article_6052_25dd7a106064d5456db20d3103e4f8b0.pdf
Evaluation of the Sparse Gash interception model in a Pinus eldarica plantation located in a semi-arid climate zone
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article
2014
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Research of the rainfall intercepted by trees is crucial in the management of water resources of afforestation in arid and semi-arid regions. The goal of this study was to evaluate the Sparse Gash model for estimation of rainfall interception (I) in a mature Pinus eldarica afforestation located in the Chitgar Forest Park in a semi-arid climate zone. Measurements of gross precipitation (PG) and throughfall (TF) were recorded on an event basis from 2009, September to 2010, April. I was calculated as the difference between PG and TF. Estimation of I was made by the Sparse Gash model, a powerful tool for estimating I, which uses canopy water storage capacity (S), free throghfall (p), and the ratio between evaporation rate from the wet canopy to the mean rainfall intensity (). For the measurement period, PG totaled 164.8 mm during 30 rainfall events and rainfall interception loss totaled 61.2 mm. The model predicted I to be 62.19 mm for all the storms analyzed. This only differed from the measured I (61.2 mm) by 0.99 mm. A linear significant relationship (r2 = 0.8772) was found between estimated I by the model and the measured I. Root mean square error (RMSE) of the estimation was 0.49 mm in a storm scale corresponds to 23.7% error. We concluded that the Sparse Gash model successfully predicted I for P. eldarica afforested regions of the semi-arid climate zone of Iran where a field measurement of rainfall interception is time-consuming and laborious.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
87
98
https://www.ijf-isaforestry.ir/article_6053_9277f9747ccb6f9b325605b33d71f017.pdf
Assessment of soil recovery and establishment of natural regeneration 20 years after stopping from ground-based skidding
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article
2014
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Ground-based skidding operations are known as an important source of damages to the residual stands and surface soil of forests. This research aims at studying the soil compaction and establishment of natural regeneration in an abandoned skid trail 20-year after cessation of timber harvest operations. For this purpose, an abandoned skid trail about 1 Km in length was chosen by field inspection at Neka-Zalemrud forest catchments. Before sampling, the skid trail was divided into three traffic intensities (low, medium and high) based on distance to log-landing. Two slope categories were then delineated for each traffic intensity. Treatments include three traffic intensities and two slope classes with three replicates for each category. Three sample plots (4×10 m) out of five ones were randomly selected for taking soil samples. The effect of soil compaction on all established regenerations was studied in same plots. Results showed that with increasing the traffic intensity and slope gradients, soil bulk density did not decrease compared to controlled areas. Soil bulk density values remained by about 6.12, 41.38 and 40.38 and 37.75, 17.34, and 45.91% for slope class 0-20% and over 20% within three traffic intensity including low, medium and high, respectively. Furthermore, results confirmed that the most tolerant and intolerant species to the compaction were beech and maple and alder in high traffic intensity, 20- year since stopping timber operations, respectively. To minimize the negative impacts of skidding operations on forest soils, permanent skid trail is required and ground-based skidding operations should be limited to areas where slope gradients do not exceed 20%.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
99
112
https://www.ijf-isaforestry.ir/article_6054_8fbac2a507eee73c60777141cac4234f.pdf
Firewood consumption by rural households in upland of the Caspian forests in the northern Iran and related factors (Case study: Upland villages in southern parts of Kheyrud Forest)
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article
2014
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The use of fuelwood has long been the main source of energy for forest dwellers. Although in recent years, it has been diminished due to the ease of access to fossil fuels. Although like many other developing countries, the use of wood is common in community adjacent or in the forest area of Iran, studies to provide a complete insight of the most important aspects of firewood consumption in these communities haven’t been conducted. Therefore, this study has been done using the methods of exploration and field research with unstructured, semi-structured and structured interviews and non-participatory observation. Most important dimensions of fuelwood usage in the forest community, such as the amount of dependence of communities with firewood, supplying of firewood, firewood consumption rates and factors affecting the use of firewood were investigated. The area of case study is forest dependent villages in Southern part of Kheyrod forest in Noshahr, Mazandaran province, Iran, including Barkan, Kolyak and Kohne-deh. The amount of firewood consumption in the village Barkan, Kolyak and Kohne-deh were 1.87, 1.96 and 2.17 cubic meters per household per month, respectively. Also total annual consumption of households in the village Barkan, Kolyak and Kohne-deh were 448.8, 369.6 and 179.8 cubic meters, respectively. According to forests area in customary units of the villages, 1.74 cubic meters of firewood were yearly harvested in average. Also there are corellations between amount of feuelwood consumption in households and family assets, as a proxy for income, distance to forested area, forest density, and the availability of alternative energy sources such as kerosene and liquefied natural gas. Further investigation is required to elaborate various aspects of subsistence wood consuming in the Caspian forests.
Iranian Journal of Forest
Iranian Society of Forestry
2008-6113
6
v.
1
no.
2014
113
125
https://www.ijf-isaforestry.ir/article_6055_13c587cb93f114b97a0d1cb914384033.pdf