Forest Directorate Research Articles

Resting in the forest in times of pandemonium for the betterment of life, or bushcraft in the Polish National Forests

Motives: In the context of the global health crisis caused by the COVID-19 pandemic, there is a need to develop new, safe forms of recreation and nature education.Aims: The Polish State Forests are introducing the concept of bushcraft, which has gained popularity among those willing to develop such skills. Sociological research and analysis of forest resources have helped to develop regulations for this form of recreation and a map of places where it can be practiced. The availability of information on the website of the General Directorate of State Forests is an important consideration, as it can facilitate the process of organizing recreation for participants and foresters.Results: The pilot program “Stay overnight in the forest” has been a success, attracting interest without negatively affecting forests and ecosystems. In the face of current and future pandemic challenges, such an innovative form of recreation may attract nature enthusiasts.

Response of black pine (Pinus nigra) in southwestern Anatolia to climate change

Global climate change is one of the most critical challenges facing natural ecosystems. As sedentary organisms, plant communities are especially vulnerable, with climate change significantly impacting their development, productivity, and distribution. This study focuses on modelling and mapping the potential distribution of black pine (Pinus nigra) within the Antalya Regional Forest Directorate under the SSP1 2.6 climate scenario for the years 2040, 2060, 2080, and 2100. The MaxEnt modelling method, combined with the HadGEM3-GC31-LL climate model from WorldClim, was used to assess the impact of climate change on black pine. The current distribution model results showed “good” predictive performance, with AUC values of 0.855 for training data and 0.851 for testing data. Key variables influencing the model included precipitation during the wettest quarter, annual precipitation, maximum temperature of the warmest month, and elevation. Projections indicate that the black pine’s distribution will shrink by 2040, become increasingly fragmented by 2060, and decline further by 2080, with near-total disappearance by 2100. In conclusion, this study highlights the urgent need for adaptive management strategies to address the effects of climate change on black pine forests.

Assessment of large-scale multiple forest disturbance susceptibilities with AutoML framework: an Izmir Regional Forest Directorate case

Disturbances such as forest fires, intense winds, and insect damage exert strong impacts on forest ecosystems by shaping their structure and growth dynamics, with contributions from climate change. Consequently, there is a need for reliable and operational methods to monitor and map these disturbances for the development of suitable management strategies. While susceptibility assessment using machine learning methods has increased, most studies have focused on a single disturbance. Moreover, there has been limited exploration of the use of “Automated Machine Learning (AutoML)” in the literature. In this study, susceptibility assessment for multiple forest disturbances (fires, insect damage, and wind damage) was conducted using the PyCaret AutoML framework in the Izmir Regional Forest Directorate (RFD) in Turkey. The AutoML framework compared 14 machine learning algorithms and ranked the best models based on AUC (area under the curve) values. The extra tree classifier (ET) algorithm was selected for modeling the susceptibility of each disturbance due to its good performance (AUC values > 0.98). The study evaluated susceptibilities for both individual and multiple disturbances, creating a total of four susceptibility maps using fifteen driving factors in the assessment. According to the results, 82.5% of forested areas in the Izmir RFD are susceptible to multiple disturbances at high and very high levels. Additionally, a potential forest disturbances map was created, revealing that 15.6% of forested areas in the Izmir RFD may experience no damage from the disturbances considered, while 54.2% could face damage from all three disturbances. The SHAP (Shapley Additive exPlanations) methodology was applied to evaluate the importance of features on prediction and the nonlinear relationship between explanatory features and susceptibility to disturbance.

Analysis of the development of tourism and recreation infrastructure in the forest districts of the regional directorate of state forests in Białystok

Forest areas are not only limited to the sale of timber (the economic side), but have many other advantages, such as: influence on climate, humidity, soil protection, health, harvesting of undergrowth, development of tourism and recreation (Gołos & Janeczko, 2001). The aim of the study is to analyse and evaluate the development of tourism and recreation infrastructure in forest districts belonging to the RDSF in Białystok in terms of its accessibility, construction and modernisation. Tourists are reluctant to visit places where such infrastructure does not exist or is neglected (Bański, 2014). This also serves as the main motivation for undertaking this kind of a study. The research used the method of observation, a diagnostic survey with a research questionnaire and a face-to-face interview. Forestry literature and financial and economic reports for the years 2020-2021 were also used. When analysing tourist and recreational infrastructure, it is worth mentioning the source of funds for its construction and modernization since, without financial support, its development would be impossible.

Wood harvesting efficiency analysis of regional forest directorates in Turkey: k-means clustering and data envelopment analysis approach

ABSTRACT Wood harvesting is a crucial element of sustainable forest management. Harvesting of wood and non-wood forest products has gained importance for increasing environmental services, economic development and sustainability of forests. The aim of this study was to reveal the efficiency values of regional forest directorates (RFD) for wood harvesting between 2015 and 2020 in Turkey using six input and two output variables. Data envelopment analysis (DEA) and k-means clustering analysis were used. From the results obtained, 35.7% of the 28 RFDs were efficient using the results of the input- and output-oriented Charnes, Cooper, and Rhodes (CCR) model. In the input-oriented CCR model, for inefficient decision-making units (DMUs) to become efficient, on average the variable that needs to be reduced the most is forest area, and the variable that needs to be reduced the least is allowable cutting. Conversely, in the output-oriented CCR model, an average potential increase of 23.84% in the harvest of industrial wood, and of 29.48% for fuelwood, was determined for the inefficient DMUs. In addition, according to the results of the k-means cluster analysis, it was found that the DMUs in the cluster distribution of inefficient DMUs were similar to each other in terms of location. It will make a positive contribution for inefficient DMUs to consider the efficient DMUs shown as references to reach the targeted input/output values to become efficient. In addition, the results of this study are important for enabling forest managers to make performance evaluations based on efficiency analyses.

Use of UAV Data and HEC-RAS Model for Dimensioning of Hydraulic Structures on Forest Roads

In terms of engineering standards, the dimensions of hydraulic structures such as culverts on forest roads should have the capability to drain the expected maximum discharge for a 50-year return period during their lifespan (i.e., 20 years). In Turkey, Talbot’s formula, as empirical method, has commonly been used in determining the required cross-sectional area (CSA) of the structures. However, in practice, forest road engineers in Turkey do not pay enough attention to their construction with required dimensions calculated by Talbot’s formula. In the present study, the Hydrological Engineering Centre – River Analysis System (HEC-RAS) model was used to evaluate the dimensions of installed structures in terms of their ability to drain maximum discharges, with the aim of determining the required dimensions for those that could not meet this requirement. To this purpose, the 6+000 km forest road No. 410 in Acısu Forest Enterprise, Gerede Forest Directorate (Bolu, Turkey) was selected as the study area. In total, 15 small watersheds crossed by the forest road were delineated, with only six of them having cross-drainage structures. The HEC-RAS model geometry was generated by manual unmanned aerial vehicle (UAV) flights at altitudes of 5–15 m, providing very high spatial resolution (<1 cm). The maximum discharges of the watersheds were estimated for the HEC-RAS model using the Rational, Kürsteiner, and Soil Conservation Service-Curve Number (SCS-CN) methods. Maximum discharges of 0.18–6.03 were found for the Rational method, 0.45–4.46 for the Kürsteiner method, and 0.25–7.97 for the SCS-CN method. According to the HEC-RAS hydraulic model CSA simulations, most of the installed culvert CSAs calculated by Talbot’s formula were found to be incapable of draining maximum discharges. The study concluded that the HEC-RAS model can provide accurate and reliable results for determining the dimensions of such structures for forest roads.

Mapping the forest fire risk zones using artificial intelligence with risk factors data.

Geographical information system data has been used in forest fire risk zone mapping studies commonly. However, forest fires are caused by many factors, which cannot be explained only by geographical and meteorological reasons. Human-induced factors also play an important role in occurrence of forest fires, and these factors depend on various social and economic conditions. This article aims to prepare a fire risk zone map by using a data set consisting of 11 human-induced factors, a natural factor, and temperature, which is one of the risk factors that determine the conditions for the occurrence of forest fires. Moreover, k-means clustering algorithm, which is an artificial intelligence method, was employed in preparation of the fire risk zone map. Turkey was selected as the study area because there are social and economic variations among its regions. Thus, the regional forest directorates in Turkey were separated into four clusters as extreme-risk zone, high-risk zone, moderate-risk zone, and low-risk zone. Also, a map presenting these risk zones were provided. The map reveals that, in general, the western and southwestern coastal areas of Turkey are at high risk of forest fires. On the other hand, the fire risk is relatively low in the northern, central, and eastern areas.

Impact of COVID-19 in the forestry sector: A case of lowland region of Nepal

All walks of life have been affected by COVID-19 but smallholders from developing countries have been impacted more than others as they are heavily reliant on forest and agriculture for their livelihoods and have limited capacity to deal with COVID-19. Scholars are heavily engaged in assessing the impacts of COVID-19 on health and wellbeing, gender, food production and supply, stock market and the overall economy but not on the forestry sector. Using questionnaire surveys and key informant interviews—informed by grey literature and published articles— representing Division Forest Offices, Provincial Forest Directorates, and the Ministry of Forests and Environment in Nepal, this study assessed the impact of COVID-19 on the forestry sector of Nepal. Our analysis suggests that: (1) nature-based tourism is more severely affected than other sectors; (2) private, religious and leasehold forests faced minimal impacts of COVID-19 than that of community and government-managed forests; (3) wild boar (Sus scrofa), different species of deer, and birds have been more impacted than other wild animals; (4) the price of the timber has increased significantly whereas the price of non-timber forests products (NTFPs) has decreased; and (5) illegal logging and poaching have increased but the incidence of forest encroachment has been reduced. Our study further reveals that agroforestry practices in home gardens, borrowing money from neighbors/banks/landlords and liquidating livestock remained key alternatives for smallholders during COVID-19. Many studies reported that reverse migration could create chaos in Nepal, but our study suggests that it may enhance rural innovation and productivity, as returnees may use their acquired knowledge and skills to develop new opportunities. As COVID-19 has created a war-like situation worldwide, Nepal should come up with a forward-looking fiscal response with alternative income generation packages to local living to counter the impacts of COVID-19 on the forestry sector. One of the options could be implementing similar programs to that of India’s US$ 800 Compensatory Afforestation Program and Pakistan’s 10 Billion Tree Tsunami Program, which will create a win-win situation, i.e., generate employment for reverse migrants and promotes forest restoration.

Effect of Bursaphelenchus spp. inoculation on carbohydrate concentrations of differentpine species in forest stands of Düzce Forest Directorate

The pinewood nematode (Bursaphelenchus xylophilus) is one of the most important pathogens of conifer forests worldwide that causes the pine wilt disease. This problem has increased the scientific interest in Bursaphelenchus species both in the world and in Turkey. Previously, six Bursaphelenchus species were isolated from wilted pine trees in Turkey. The main goal of this study was to investigate the effects of nematode inoculation on the total carbohydrate concentrations of tree species. Native six Bursaphelenchus species were inoculated on three pine species (Pinus pinaster, P. nigra, and P. sylvestris) under natural stand conditions. Two different doses of nematodes (2000 and 20,000) were used for inoculation. For each treatment, three trees of each species were inoculated. The total carbohydrate concentrations were differed significantly among tree species, nematode species and between nematode doses. The total carbohydrate concentration values were higher in P. pinaster than both P. nigra and P. sylvestris. These results may suggest that pine species responded to nematode inoculation by changing the amount of TCC.

ANALYSIS OF THE DYNAMICS OF LAND USE AND COVER IN THE DISTRICT OF INHARRIME (1980-2020)

The analysis of the dynamic use and land cover in the District of Inharrime in the period 1980- 2020 consisted of the interpretation of the images obtained to partir of the sensors on board in satellites of different times. In this work, landsat 5 images were classification for the years 1980, 2000 and 2020, followed by validation (confusion matrix) that shows the quality of the generated model. The methodology used was the bibliographic review, use of Remote Detection techniques and Geographic Information Systems that on the one hand allowed the acquisition and spatial analysis and on the other facilitated the classification of images from the study area, the handling of the existing database (BDCOV250) of the National Center for Mapping and Remote Sensing of the National Directorate of Land and Forests. As a final product, maps of land use and land cover were elaborated for the three years under analysis. Based on these results, it was possible to make the detection of changes that allow verifying the classes that changed over time and those that remained unchanged. The mapping of land use and coverage based on satellite images will allow planners to become aware of the current situation of the district, for actions that allow the creation of means for conservation, rational and conscious use of existing forest resources in the district.

Potential forest fire risk evaluation in Poland

Abstract The term forest fire risk means the existence of such conditions that would make possible the occurrence of a fire in the forest environment. The base for the effectiveness of a forest fire protection system is the evaluation of the forest fire risk followed by adequate organization of the system. This article presents methods for determination of the forest susceptibility to fire known as potential forest fire risk. The below presented methods were developed by Forest Research Institute as the results of the projects commissioned by the General Directorate of State Forests. The forest fire risk category and stand flammability classes are the methods included here. The forest fire risk category was elaborated already in 1975 for the first time. Until today, after the last modification in 2008, it is the fundamental document for the polish forest fire protection system. The purpose of this modification was to increase the determination accuracy of the fire risk category of all polish forest, regardless of its ownership type and at the different administrative level. The categorization method, however, doesn’t reflect the fire risk in micro scale. The attempt to solve that problem was made in 2018 while developing the methodology of stand flammability classes. It was assumed that ground cover fuel models will be developed for the most flammable forest habitat types including ground cover types, dominant species, age class and geographical localisation.

Territorial Diagnosis of Ecotourism in Tunisian Mountain Protected Areas: Stakeholders, Positions and Power Relations

Since the 2000s, projects and studies have been multiplied for the development of ecotourism in Tunisian protected areas. Despite these efforts, the Tunisian case faces several failures. As part of this study, we aim to provide elements of reflection on a contractual scheme for a sustainable territorial development plan by ecotourism, around mountain protected areas in Tunisia. For this reason, we adopted the strategic prospective analysis revealing and analyzing the relationships between the different actors involved in ecotourism in the protected area. A Matrix of Alliances, Conflicts, Tactics and Objectives among MACTOR actors was developed in a participatory way to analyze the actors' strategies. After doing a triangular analysis which consists in to an inventory of the projects and studies about the protected area of Ichkeul and Cape Negro-Jbel Chitana, semi-structured interviews with personals from different sectors, we invited the actors met on the field or mentioned in the projects in a workshop organized in partnership with the General Directorate of Forests in Tunis in order to identify the different categories of actors and analyze the balance of power between them. This analysis is done through a matrix notation system. Eight categories of actors have been identified: international cooperation, resource managers, politic policy etc. Thanks to the matrix notation systems, we have been able in a participative way to classify these eight categories of actors into four types: dominant actors, relay actors, autonomous actors and dominated actors. Thus, the MACTOR method allowed us to identify actors who played a role in the development of ecotourism projects in Tunisia and to be able to diagnose their balance of power. This allowed showing the multidisciplinarity and complexity of the sector as well as the strong influence of certain actors such as international cooperation and public decision-makers. To conclude, the MACTOR analysis of the ecotourism actors in the protected area of Ichkeul and Cap Negro-Jbel Chitana enters into a methodology of prospective territorial analysis in this area to understand the points that caused the failure of several experiments.

PRIORITIZING THE POTENTIAL OF NON-WOOD FOREST PRODUCTS FROM ARAD COUNTY BY USING THE ANALYTICAL HIERARCHY PROCESS

Romanian forest management plans and policies, traditionally focused on timber production, need to reconsider the NWFPs (non-wood forest products) importance in the development of the socio-economic sector. Within the country’s forestry economy, the nature, quantity and weight of NWFPs are variable factors from one county to another, influenced to a large extent by the area covered by forests. The aim of this study is to unravel the most important NWFPs available in Arad County. In order to analyze the potential of NWFPs, data from the forest management plans of the ten subunits within the structure of the Arad Forest Directorate and statistical data from various institutions were used. In accordance with the purpose of the study, NWFPs were clustered into four categories as designed in the European project COST FP1203 European Non-Wood Forest Products (NWFPS) Network: mushrooms, tree products, understory plants and animal origin products. Eight different types of NWFPs were identified and analyzed using the analytic hierarchy process. Potential NWFPs were prioritized in accordance with the 19 criteria selected, and thus the most promising NWFPs were determined. Subsequently, AHP results were implemented in the Choice Expert Desktop software package. The results of the study indicate that Coturnix coturnix and Vulpes vulpes are in the top of the most promising NWFPs. More importantly, the obtained results can help to better address the management of NWFPs from Arad County.

Natural Enemies of Cinara cedri Mimeur 1936 (Hemiptera: Aphididae) in Cedar Forests in Isparta Regional Forest Directorate

enemies of cedar aphid (Cinara cedri Mimeur, 1936) (Hemiptera: Aphididae) in cedar (Cedrus libani A. Rich.) forests. Area of study: Specimens were collected from 40 areas in Isparta Regional Forest Directorate cedar forests. Material and methods: At each site, specimens were randomly collected from infested shoots. Shoots were cut and put in plastic bags and containers and were brought to the laboratory, examined with a stereomicroscope. The adults obtained were prepared and sent to specialists for identification. Main results: Twenty eight species of insect enemies were found, most of them coccinellid and syrphid predators. Harmonia axyridis Pallas, 1773, Anatis ocellata (Linnaeus, 1758) (Coleoptera: Coccinellidae), Asaphes vulgaris Walker, 1834 (Hymenoptera: Pteromalidae) and Pauesia anatolica Michelena, Assael & Mendel, 2005 (Hymenoptera: Braconidae) were found for the first time in the study area. Moreover, 17 species were firstly determined as a natural enemy of Cinara cedri. Highlights: In this study, new records were identified for study area. Moreover, 17 species were firstly determined as a natural enemy of Cinara cedri.

Determination of Some Stand and Site Parameters Influencing the Snow Damage in Trees: A Case Study of Boyabat Forest Enterprise, Turkey

Aim of Study: Determination of the snow damage triggering stand and site parameter on trees.Area of Study: Damaged compartments of Yedicam and Burnuk Forest Directorates, #234 and #116, within Boyabat Forest Enterprise of Kastamonu Regional Directorate of Forestry.Material and Method: Two damaged and two control compartments from each directorate were compared to find if any site or stand parameters are related to the snow damage occurred in the area during 2014-2015 winter. Statistical analysis were carried out to test the significance of the parameters.Main results: Age, relative density, the number of trees, basal area and stand volume of the stand parameters, and slope, site class, terrain roughness and soil depth of the site parameters were statistically linked to the snow damage.Research highlights: The climate is a force to be reckoned with. New strategies must be devised and put into action in forest management. Studies have shown the mishaps. The lessons should be taken from the past experiences. Apparent mistakes must gradually be eliminated.

Distribution, biology, morphology and damage of Cinara cedri Mimeur, 1936 (Hemiptera: Aphididae) in the Isparta Regional Forest Directorate

DOI : 10.26650/forestist.2019.346284 In 2015-2016, a study was performed examining the distribution, colony dispersion in tree canopies, occurrence rate in shoots at different ages, morphology, and the damage of the cedar aphid (Cinara cedri Mimeur 1936) (Hemiptera: Aphididae) This study was completed alongside biological observations in the Isparta Regional Forest Directorate. This study was conducted across 46 sites at an elevation of 820-1738 meter (m) and the distribution of this species was determined by a survey. Compared to other sites, the Cinara cedri (C. cedri) population was found to be higher in 10 sites with young stands with an average height of 1000-1200 m. These sites were established through plantation. Colonies were typically observed on the shoots from the previous year and on branch axils. They were found to feed on shoot tips and trunks of young trees and preferred shoots with a diameter of 1.0-1.5 centimeter (cm) on the southern and eastern aspects of the trees. It was observed that C. cedri mostly fed on shoots of the previous year, which caused the needles to dry and turn red. Damage was observed especially on young trees from which the dried needles fell and defoliation was concentrated particularly on the shoot tips and tops of the trees. It was found that honeydew was secreted by those insects fed with sap, and this secretion then covered the needles, shoots and branches, resulting in fumagine. The populations overwintered as eggs and then nymphs hatched during the first week of April. The adult stage was reached after completing four nymph periods over a time span of between one week and 10 days. These adults then reproduced parthenogenetically, with winged viviparous individuals appearing between May and June, and oviparous emerging in October. The final stage of the cycle was a period of mating and then egg-laying.

A silvicultural management tool for the Oriental beech (Fagus orientalis Lipsky) forests

ABSTRACTStand density management tools help forest managers and landowners to more effectively allocate growing space so that specific silvicultural objectives can be met. Due to the economic importance of Oriental beech (Fagus orientalis Lipsky) forests in Turkey, a stand density management tool was developed for this species to optimize regeneration success rate and tree growth. For the development of this tool, named stand density management diagram (SDMD), we utilized forest inventory data from the Kastamonu Regional Forest Directorate in Turkey. Previously published forest management approaches and models were employed during the development of the tool. The SDMD illustrates the relation among four forest indexes: the basal area per hectare, number of trees per hectare, forest stand volume per hectare, and quadratic mean diameter of the beech stands. The stand stocking percent (SSP) can be determined based upon any two of these four measurements. The results suggest that SSP is a better predictor of tree growth than BA in Oriental beech forests. The newly developed SDMD allows for a more effective use of the growing space to achieve specific silvicultural objectives including tree regeneration, timber production, thinning planning, and wildlife protection in Oriental beech forests.

Rola funduszu leśnego w wyrównywaniu niedoborów finansowych w nadleśnictwach

The company Lasy Panstwowe (State Forests) is financially autonomous and covers the costs of its activityfrom its own revenues (Chapter 8, Article 50, of the Act). It is not its objective to maximize profits but to perform economic, productive and non-productive natural and social functions. In order to ensure that such activities may be conducted throughout Poland, even in those forest districts where the costs are higher than the revenues generated, the forest fund has been established to offset financial deficits in loss-making forest districts. The forest fund is a financial instrument spent on tasks defined in the forest act, especially to offset deficits due to the costs of forest management, joint ventures of the company’s organizational units, creation of the infrastructure necessary to conduct forest management, as well as evaluating and estimating the forests and their resources. The rules of forest fund redistribution are not clearly specified, which is why each Regional Directorate of State Forests (RDSF) adopts different criteria relating to its redistribution. The aim of the paper is to define the role of the forest fund in balancing financial deficits in forest districts on the basis of data received from General Directorate of State Forests for the year 2014. The write-off in 2014 amounted to 14.5% of timber sales for individual RDSFs. Each RDSF differentiates the write-off and the subsidies from the forest fund for individual forest districts and inf luences liquidity and profitability of the forest districts it supervises.This paper was prepared on the basis of selected literature, analysis of materials received from the General Directorate of State Forests, own analyses and the experience gained in the course of professional work in the State Forests.

The use of view analyses in shaping a forest landscape in the vicinity of water reservoirs

Abstract An increasing importance of the social functions of the forest entails the necessity to modify forestry management in a way which would ensure its social acceptance. This mainly concerns those parts of the forest that are “most visible”, in the surroundings of roads, tourist trails, as well as water bodies. The article discusses the importance of view analyses in forest landscaping. On the basis of the adopted methodological assumptions, the assessment of landscape resources of the forest in the vicinity of a water reservoir in the Kielce Forest District (Radom Regional Forest Directorate) has been made. Available ortophotomaps and aerial photographs taken by UAVs were used for view analyses together with elevation data collected through airborne laser scanning. The results obtained allow to make recommendations for the protection of the reservoir exposure as well as engineering forest management and silviculture. Consequently, the inclusion of visual analyses into the planning stage enables verification of the quality of forest management plans.

Heavy Metal Pollution Around International Hatay Airport

In this study, it was aimed to determine the heavy metal pollution in the agricultural lands around Hatay airport and travel possible alteration in the amount of heavy metal on the land in accordance with the distance to the airport. For this purpose, the airport was chosen as the center and 27 soil samples were obtained around the airport at 2 km intervals in depth ranging from 0 to 30 cm. Lead (Pb), cadmium (Cd), nickel (Ni), chrome (Cr), cobalt (Co), aluminium (Al), iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) elements in soil samples were analysed using MP-AES instrument by DTPA method. (3 repetition for each sample). As a result of the analysis, heavy metal concentrations were found as Pb 0-1.45 mg/kg, Cd 0-0.220 mg/kg, Ni 0-3.95 mg/kg, Cr 0-0.780 mg/kg, Co 0-0.270 mg/kg, Al 0-0.700 mg/kg, Fe 1.47- 16.2 mg/kg, Cu 0.400-5.35 mg/kg, Mn 0-19 mg/kg and Zn 0.050-3.14 mg/kg. When comparing the obtained data through this study with allowable concentrations of heavy metals in soil of Environment and Forest Directorates Guidance, it was determined that the heavy metal concentration of the soil does not pose any problems in terms of heavy metal pollution. Besides, iron concentration was decreased when the distance to the airport is increased.