Effects of wheeled cable skidder on rut formation in skid trail-a case study in Hyrcanian forest

The impact of skidding operations on forest soils can be divided into three major categories： soil profile disturbance, soil compaction, and soil puddling and rutting. The present study was designed as a factorial experiment in the Kheyrud Forest with a Timberjack cable skidder to evaluate the influences of number of machine passes and soil moisture of skid trails on rutting over a fine-grained soil, and to quantify these effects. The effects of soil moisture of 20% 30%, 30% 40% and 40% 50% and different levels of compaction were studied. Compaction treatments were applied using different numbers of skidding passes （1, 5, 10, 15, 20, 25, 30 times）. Result shows that an increase in the number of machine passes could increase rut depth, but the majority of rutting was occurred after the initial few machine passes. Also rut depth at soil moisture of 40% 50% was higher than rut depths at soil moisture of 30% 40% and 20% 30%. The average rut depth in soil with 20% 30%, 30% 40% and 40% 50% moisture was 17, 22 and 35 cm, respectively. Rut depths were increased significantly with soil moisture and number of machine passes. It is suggested that skidding operations should be planned when soil conditions are dry in order to minimize rutting., but if skidding must be done under wet conditions, the operations should be stopped when machine traffic could create deep ruts.

Effects of geometric design of forest road and roadside vegetation on traffic noise reduction

Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car （Land Rover） relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type （coniferous and hardwood） in 40 rectangular plots of three widths （25, 100 and 300 m） and 50 m length that were randomly demar- cated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of q-1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30-45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % （67 dB） and 3-8 % （71.2 dB） in comparison with slopes greater than 8 % （77.8 dB）, （p 〈 0.05）. Pinus brutia L. reduced the noise level more （about 6 dB） in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.

Modeling of forest soil and litter health using disturbance and landscape heterogeneity indicators in northern Iran

This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.

Traditional mule logging method in Hyrcanian Forest: a study of the impact on forest stand and soil

We inventoried plant regeneration and soil compaction along mule trails to evaluate damage to forest stands and regeneration follow- ing mule hauling before and after operations in Kheyrud Forest in the Hyrcanian Forest in northern Iran. About 22% of regenerating plants on mule trails were damaged following mule logging, and damage to trees was observed. In harvested units after timber extraction, 4.3% of the total area （12 ha） was covered with mule trails. Mule passes and slope gradi- ent, and twofold interactions between mule passes x slope gradient had no significant effect on soil bulk density （p 〈 0,05）. Mule iogging had a statistically significant effect on soil bulk density along the mule trails before and after mule passes. Soil bulk density increased Significantly as mule passes increased in number. The degree and level of compaction did not differ with trail slope. With respect to damage to residual stands and seedlings, soil compaction and disturbance to soil, traditional mule log- ging is the preferred skidding method in the steep terrain conditions in the Hyrcanian Forest in northern Iran.

Accumulation of heavy metal in Platanus orientalis, Robinia pseudoacacia and Fraxinus rotundifolia

Plants are capable of reducing environmental pollutions through uptaking contaminants in their tissues. In the study site, twenty one-year-old leaves and shoots as well as twenty soil samples were sampled and analyzed by Inductively Coupled Plasma （ICP）. We investigated the uptaking ability of lead （Pb） and cadmium （Cd） by the leaves and shoots of Platanus orientalis, Robinia pseudoacacia and Fraxinus rotundifolia in Karaj city, the western Tehran, Iran. We also evaluated the total metal accumulation capacity by using metal accumulation index （MAI）. Results indicated that there was no significant difference in uptaking contents of Cd and Pb in the leaves among the trees. However accumulation of Cd in shoots of F. rotundifolia and R. pseudoacacia was significantly higher than that of P. orientalis. The accumulation of Pb in shoots of R. pseudoacacia was significantly higher than the other species. The amount of Pb in the soil of the study area was significantly higher than Cd. Concentrations of Cd and Pb in leaves of the three species are in the ranges of 2.4 2.7 mg Kg-1 and 7.1 14.4 mg Kg-1 , respectively. R. pseudoacacia had the highest MAI value for leaves （2.21） and F. rotundifolia had the highest MAI value for shoots （2.4）.

Cadmium and lead effects on chlorophyll fluorescence,chlorophyll pigments and proline of Robinia pseudoacacia

Heavy metal contamination is one of the most important abiotic stresses affecting physiological activities of plants.We investigated the effects of cadmium（Cd） and lead（Pb） on chlorophyll fluorescence（Fv/Fm,Fo,and Fm）,photosynthetic pigments（chlorophyll a and b）,and proline in one-year-old seedlings of Robinia pseudoacacia.The seedlings were treated twice over a period of 10 days with Cd and Pb at concentrations of 0,250,500,1000 and2000 mg L-1.Saline solution containing Cd and Pb was sprayed on the leaves.Chlorophyll and proline contents were measured after 10 days.Chlorophyll fluorescence of R.pseudoacacia was affected slightly by high concentrations（1000,2000 mg L-1） of Cd and Pb.Chlorophyll a and a/b increased at 1000 and 2000 mg L-1of Cd and proline content of leaves was similar in all treatments of Cd and Pb.Our results indicated that photosynthetic sensitivity of R.pseudoacacia to Cd and Pb contamination was weak.Photosystem II chlorophyll pigments were not damaged by Pb and Cd stress.We conclude that chlorophyll fluorescence along with chlorophyll and proline contents are useful indicators of Cd and Pb stresses in R.pseudoacacia which widely planted in urban polluted regions in Iran.

Effects of soil compaction on growth variables in Cappadocian maple(Acer cappadocicum) seedlings

This study investigates the effects of increasing soil penetration resistance(SPR) on seedling morphology and seedling architecture. When seedlings of deciduous Cappadocian maple(Acer cappadocicum Gled.) were grown in a greenhouse in a loamy soil under a wide range of soil compactions, all morphological variables studied changed significantly with increasing SPR. The relationships between increasing SPR and all morphological responses except lateral root length followed a negative quadratic curve. All biomass variables except lateral root biomass showed a bell-shaped response with respect to SPR, with a maximum biomass variable between 0.6 and1.2 MPa, decreasing at higher soil compaction values. All allocation ratios were significantly affected by soil penetration resistance. Biomass allocation to roots was also affected by soil compaction. There was not a significant relationship between the specific stem length and increasing soil penetration resistance. The specific root length showed two trends to increasing SPR; it first decreased in response to the moderate compaction treatment(up to about 1.2 MPa), then increased significantly. We concluded that increasing soil compaction caused morphological changes to root and shoot sections of A.cappadocicum seedlings.

Operational impacts to residual stands following ground-based skidding in Hyrcanian Forest, northern Iran

Hyrcanian （Caspian） Forest in northern Iran has a richness of biological diversity, with endemic and endangered species. The usage of ground-based skidding is well accepted practice for the extraction of timber from the forest, but this operation has tended to cause the greatest environmental problems. The aims of the study were to evaluate and comparison of operational impacts, residual stand damage, regeneration, and to quantify these effects such as： the extent of the damage, wounding patterns, size and distribution after logging operations that utilized two different methods： short log and long log. A Timbetjack cable skidder was used and the study location was in the Kheyrud Forest. Post harvesting assessment of damage to the residual stand was compared along skid trail by 100% inventory method and also for the assessment of regeneration damage along winching strips. The results show that along winching strips the percentage of damage to the regeneration was 44% and 36%, while the tree damages along skid trails reached 2.3% and 4.1% in the short log and long log methods, respectively. The greatest average amount of damage to a bole occurred along the first 1 m up from the ground （97%） and also within 4 m of the skidder centerline （80%）. These results show that the short log method causes less damage to the residual stand than the longog method. Tree location to skidder trail appears to have a significant effect on the number and height of scars on a tree. Well designed and constructed trails should be wide enough to allow wood extraction from the forest. Damage to the residual stand might be reduced by proper planning and training of logging crews.

Wood anatomical changes due to uptake of cadmium and lead from contaminated soils in Acer velutinum seedlings

We investigated wood anatomical changes due to uptake and accumulation of cadmium and lead from contaminated soils in Acer velutinum Boiss seedlings. Two-year old seedlings were exposed for 180 days to soil concentrations with varying cadmium and lead concentra- tions. We measured three wood anatomical traits, average vessel area （gm2）, vessel number per square millimetre, and vessel lumen area per- centage （%）. For assessing the cadmium and lead accumulation, we measured the concentrations in the soil, leaf, stem, and root. Average vessel area and vessel lumen area percentage were similar （p〉0.05） in control and treated seedlings. Vessel number per square millimetre showed a decreasing trend from pith to bark in control and treated seed- lings, and the trend was more pronounced in treated seedlings. We con- clude that vessel number per square millimetre in A. velutinum is influ- enced by soil contamination. A. velutinum Boiss is not a suitable species for remediation of soils contaminated by cadmium and lead but it can be used as an indicator of the soil lead contamination, because lead concentrations in seedlings increased with increasing amount of lead in the soil.

Response of Platanus orientalis leaves to urban pollution by heavy metals

Atmospheric pollution is an important concern in urban environments.The impact of urban pollution on the physiological,biochemical and anatomical properties of leaves of oriental plane(Platanus orientalis L.)was studied.The leaves were collected from an urban site(Tehran,Iran)and a non-urban forest park(Chitgar Forest Park).Anatomical(stomata,parenchyma,and cuticle)and physiological(chlorophyll content,enzyme activities)properties were analyzed.The concentrations of Cd(cadmium),Pb(lead),Ni(nickel),and Cr(chromium)in leaves were significantly higher and Zn(zinc)lower at the urban site relative to the forest park.Chlorophyll a,total chlorophyll,and carotenoid content in leaves of the urban site were significantly less than those of the forest park,but there was no significant difference in chlorophyll b.In addition,the activities of superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase in urban leaves were significantly higher than in the leaves of the forest park.In the urban area,leaves experienced a significant decrease in leaf surface area,stomata density,stomata pore area,epidermis,and spongy mesophyll thickness,but a significant increase in cuticle and palisade thicknesses relative to forest park leaves.The increase in enzyme activities may indicate that the trees are attempting to cope with increased reactive oxygen species(ROS)because of pollution-induced stress.Our study suggests that oriental plane trees alter their physiological and anatomical properties when living in a polluted urban environment.

Image texture indices and trend analysis for forest disturbance assessment under wood harvest regimes

Effective disturbance indices for Hyrcanian forests in Kheyroud,Nowshahr,Iran were determined.The study area was divided into landscape mosaics based on ecosystem parameters including profile type,slope and elevation.Co-occurrence texture indices were derived as forest disturbance factors on the first five bands of Landsat TM,ETM+and OLI images for the prevailing wood harvest disturbance regimes.These indices were screened using ten types of trend analyses and used for modeling disturbance of the harvesting regime through artificial neural networks.The results show that the selected indices can be useful in distinguishing areas with different disturbance intensities and as such,used in the context of health assessment through the health distance method.The accuracy of the health maps derived from the indices[increasing disturbance]led to give rise higher disturbance classification accuracy.

Evaluation of the Strategic Factors of the Management of Protected Areas Using SWOT Analysis—Case Study: Bashgol Protected Area-Qazvin Province

The majority of Iranian protected areas are being affected by human activities. Such areas demand continuous monitoring into account due to quality loss problem. This study identifies the weaknesses and strengths as well as opportunities and threats of Bashgol protected area and analyzes them using SWOT matrix in order to provide an efficient managerial strategy. Following the identification of factors, experts’ opinion was collected using questionnaire. Then, the factors were scored based on IFE (Internal Factors Evaluation) and EFE (External Factors Evaluation) tables and were weighted using AHP and EXPERT CHOICE. Totally, 16 strengths and opportunities were determined as the advantages of this area and 22 weaknesses and threats were identified as the limitations and straits. The final scores of IFE and EFE were 2.468 and 2.261, respectively and both are below 2.5 indicating that the area is in defensive state. According to quantitative strategic planning matrix (QSPM), “attracting required credits for the completely implementation of the comprehensive management plan of the area” was determined as the most important strategy (score = 6.365).

Evaluating the Impact of Workshop Management on the Progress of Road Construction Projects(Case Study:Road Construction Projects of Tehran Province)

Construction projects,including road construction,are very important.Therefore,a lot of money is spent on these projects every year.So,the lack of proper planning will increase the cost and cause irreparable damage to the country.The role of workshop management is one of the most important factors in increasing the cost of these types of projects.Generally,workshop management plays a very important role in improving the quality and quantity of projects and has an important place in the project implementation process.Therefore,this study evaluated the impact of workshop management on the progress of road construction projects on a case-by-case basis in road construction projects in Tehran province.According to the purpose of the research,this study was a descriptive-survey type.In addition,the tool used in this research was a questionnaire.The statistical population of this research included all experts and specialists in road construction projects,among whom 65 people were selected by snowball method.Then the collected data were analyzed using SPSS software.The results of this study showed that the management of the workshop and its role in the control and implementation of projects is a complex process,which can be implemented at high levels and effectively by combining scientific and experimental training.And a very important point in the discussion of workshop management is applying scientific management to the use of valuable experiences from others.Because management knowledge not only does not negate the use of these experiences,but also emphasizes the necessity of using them.In other words,improving the knowledge of workshop management is one of the requirements for the implementation of value engineering in construction projects,especially road construction,and it is very important.

Soil fixation and erosion control by Haloxylon persicum roots in arid lands, Iran

Vegetation roots contribute to soil fixation and reinforcement, thus improving soil resistance against erosion. Generally, the amount of soil fixation presented by roots mainly depends on root density and tensile strength. In the present study, we conducted the research in order to further understand the biotechnical properties of Haloxylon persicum and also to quantify its role in increasing soil cohesion in arid lands of Iran. Ten H. persicum shrubs were randomly selected for root distribution and strength investigations, in which five samples were set on flat terrain and other five samples on a moderate slope terrain. The profile trench method was used to assess the root area ratio(RAR) as the index of root density and distribution. Two profiles were dug around each sample, up and downslope for sloped treatment and north and south sides for flat treatment. The results showed that RAR increased with increasing soil depth and significantly decreased in 40–50 cm layers of downhill(0.320%) and 50–60 cm for uphill(0.210%). The minimum values for the northward and southward profiles were 0.003% and 0.003%, respectively, while the maximum values were 0.260% and 0.040%, respectively. The relationship between the diameter of root samples and root tensile strength followed a negative power function, but tensile force increased with increasing root diameter following a positive power function. The pattern of increased cohesion changes in soil profile was relatively similar to RAR curves. The maximum increased cohesion due to the presence of roots in uphill and downhill sides were 0.470 and 1.400 kPa, respectively. In the flat treatment, the maximum increased cohesions were 0.570 and 0.610 kPa in northward and southward profiles, respectively. The analysis of variance showed that wind and slope induced stresses did not have any significant effect on the amount of increased cohesion of H. persicum. The findings served to develop knowledge about biotechnical properties of H. persicum root system that can assist in assessing the efficiency of afforestation and restoration measures for erosion control in arid lands.

Environmental impact prediction using remote sensing images

Environmental impact prediction is an important step in many environmental studies. A wide variety of methods have been developed in this concern. During this study, remote sensing images were used for environmental impact prediction in Ro-batkarim area, Iran, during the years of 2005～2007. It was assumed that environmental impact could be predicted using time series satellite imageries. Natural vegetation cover was chosen as a main environmental element and a case study. Environmental impacts of the regional development on natural vegetation of the area were investigated considering the changes occurred on the extent of natural vegetation cover and the amount of biomass. Vegetation data, land use and land cover classes (as activity factors) within several years were prepared using satellite images. The amount of biomass was measured by Soil-adjusted Vegetation Index (SAVI) and Normalized Difference Vegetation Index (NDVI) based on satellite images. The resulted biomass estimates were tested by the paired samples t-test method. No significant difference was observed between the average biomass of estimated and control samples at the 5% significance level. Finally, regression models were used for the environmental impacts prediction. All obtained regression models for prediction of impacts on natural vegetation cover show values over 0.9 for both correlation coefficient and R-squared. According to the resulted methodology, the prediction models of projects and plans impacts can also be developed for other environmental elements which may be derived using time series remote sensing images.

Incremental adaptation strategies for agricultural water management under water scarcity condition in Northeast Iran

Population growth and climate changes as two synergistic phenomena have damaged water resources nationwide and worldwide.The water resources available for agriculture is one of the most critical limiting factors in food production enhancement in Iran.Agriculture must tackle the challenge of supplying the increasing demands for food due to population growth.For this purpose,we must get acquainted with how farmers make decisions and their adaptations to water scarcity conditions by studying their adaptation strategies.In this case,we can predict the farmers’behaviors by recognizing the optimal adaptation strategies under water scarcity crisis.This study aims to provide a model to examine and analyze the farmers’behaviors in the realm of water scarcity and the contributing factors to it,facilitating a better understanding of the potential implications of such scarcity,introducing the adaptation changeability procedures for agricultural water management and assistance to farmers to adapt,and developing the actions for mitigating the vulnerability of agriculture sector in Iran.In this study,175 farmers in Northeast Iran were interviewed to conduct an applied research by questionnaire survey.The research tool was a researcher-made questionnaire designed based on the theoretical literature and designed model.According to the research,the model of incremental adaptation strategies could determine the effects of a set of psychological and socioeconomic factors and the formation of adaptation decisions in water resources management under water scarcity conditions.The results indicated that the concern and attitude,farmers’knowledge and technical skill,self-efficiency and risk-taking level,social capital and information availability for farmers,and the internal norm are significantly and positively correlated in this model.The results provide a proper understanding of farmers’sustainable decision-making and a perspective on contributing factors to the strategy framework and improved policies in the form of incremental adaptation strategies when facing water scarcity in agricultural water resources management.Thus,this study will respond to deal with water scarcity by changing farmers’behaviors in dry lands and water scarce regions.

Temperature variability in northern Iran during the past 700 years

Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,which have contributed to understanding climate changes over the past millennium[1].Under the PAGES2K framework[2],a tree-ring network of the Eurasian continent