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Öğe Bulk precipitation chemistry at the forest and forest village(Elsevier Science Inc, 2013) Gökbulak, Ferhat; Şengönül, Kamil; Serengil, Yusuf; Yurtseven, İbrahim; Uygur, Betül; Özhan, Süleyman; Özcan, MehmetThe objectives of this study were to characterize and compare selected physical and chemical properties of precipitation in a broadleaf mixed forest and a village located in the same forest in order to determine the influence of the village on the atmospheric environmental quality of the forest ecosystem. Bulk precipitation samples were collected weekly from October 2005 to July 2011. Precipitation samples were analyzed for pH, electrical conductivity (EC), turbidity, total suspended particles (TSP), total alkalinity (CaCO3), alkalinity (HCO3-), chloride (Cl-), total hardness (CaCO3), Ca hardness (CaCO3), calcium (Ca2+), magnesium (Mg2+), organic matter, total nitrogen (N), sodium (Na+), potassium (K+), nitrate (NO3)(-), phosphate (PO4)(3-), iron (Fe), aluminum (Al), ammonium (NH4)(+), and sulfate (SO4)(2-). The precipitation samples from forest and forest village were significantly different from each other for EC, total alkalinity (CaCO3), HCO3-, Ca hardness (CaCO3), Ca2+, total N, K+, NO3-, and NH4+. Regardless of the study sites, PO43- and Mg2+ were dominant anion and cation, respectively. The orders of cation and anion concentrations were similar for both study sites and they were in descending order of Mg2+ > Ca2+ > Na+ > K+ > NH4+ > Fe > Al > H+ and PO43- > HCO3- > SO42- > Cl- > NO3-, respectively. Overall average monthly values of precipitation characteristics did not show significant difference between months except for pH, EC, total alkalinity (CaCO3), and HCO3-. Significant correlations were found between SO42- and pH, Ca2+, NH4+ and between NO3- and NH4+ for the precipitation event at the forest site. Both study sites had pH values higher than 5.6 due to the neutralization of SO42- and NO3- by NH4+ and Ca2+. Significant correlation coefficients found between the study sites for the same precipitation parameter indicated that both study sites were under the influence of the same emission sources. (C), 2013 Elsevier B.V. All rights reserved.Öğe Düzce meralarında yetişen bazı tıbbi ve aromatik bitkilerin verimlerinin belirlenmesinde bitkisel özelliklerinin kullanımı(2023) Özcan, Mehmet; Ayteğin, Ahmet; Akın, ÖzcanDünya üzerinde mera alanları sadece hayvanlara kaba yem temin eden alanlar olarak değil bitki tür çeşitliliği açısından da önemli bir yere sahiptir. Mera alanlarında yetişen birçok bitki baharat ve ilaç sanayiinde yaygın olarak kullanılabilmektedir. Bu nedenle meralar bu özelliklere sahip bitkilerin toplanarak ekonomiye kazandırılması açısından da önemli bir doğal kaynaktır. Son yıllarda bu tür bitkilerden elde edilen hem nihai tüketim hem endüstriyel alanlarda değerlendirilen yaprak, çiçek, meyve gibi ürünlere talep artmaktadır. Bu nedenle meralarda yetişen bu bitkilerin yıllık verimlerinin bilinmesi ve buna bağlı olarak üretim planlarının hazırlanması önemli bir konu olarak karşımıza çıkmaktadır. Bu tür bitkilerin verimlerinin belirlenmesinde doğrudan biçim veya dolaylı yöntemler kullanılmaktadır. Çalışmada Düzce ili mera alanlarında yetişen tıbbi ve aromatik bitki özelliğine sahip Clicopodium vulgare L. subsp. vulgare, Thymus longicaulis C.Presl subsp. longicaulis ve Cistus creticus L. bitkilerinin bitkisel özellikleri ile verimleri arasındaki ilişkiler incelenmiştir. Çalışma sonucunda incelen her üç bitki türünün de bitkisel özellikleri ile verimleri arasında istatistiksel olarak önemli ilişkiler bulunmuştur. Bu bağlamda her üç bitki türünün verimlerini belirlemede bitkisel özelliklere bağlı olarak geliştirilen denklemlerin kullanılması ile verimlerinin daha kolay tespit edilebileceği belirlenmiştir.Öğe Düzce Odayeri yaylasında bazı ıslah yöntemlerinin kuru ot verimi üzerine etkileri(2019) Gedikli, Hasan; Karagül, Refik; Özcan, MehmetEn önemli doğal kaynaklarımızdan biri olan yaylalar, ülkemizin hemen hemen her bölgesinde bulunmakta ve hayvancılığın kaba yem ihtiyacının en ucuz karşılanabileceği alanlar olarak ülke hayvancılığına önemli katkılar sunmaktadır. Ancak yayla meralarında yıllardır süre gelen bilinçsiz otlatma baskısı bugün birçok yaylanın klimaks bitki örtüsünden uzaklaşarak çalı ve yabancı otlarla kaplanmasına neden olmuştur. Ancak, bu alanların hayvancılık üretimine olan katkısı, mera durumu ve yapısına uygun rehabilitasyon yöntemlerinin uygulanmasıyla arttırılabilir. Ülkemizde düşük rakımlı mera alanlarının ıslahı konusunda birçok çalışma yapılmışken, yaylalarda (dağ merası) pek fazla çalışma yapılmamıştır. Bu bağlamda çalışmada yem verimi bakımından orta mera sınıfına giren Odayeri yaylasında farklı ıslah yöntemlerinin yaylanın kuru ot verimi üzerine etkileri araştırılmıştır. Çalışma 2016-2017 yıllarında, 1200 m rakımda ve Türkiye yayla ortalamasına yakın olan Düzce ili sınırları içerisinde yer alan Odayeri Yaylasında gerçekleştirilmiştir. Araştırma rastlantı parselleri deneme desenine göre 6 işlem (kontrol, tohum ekimi, herbisit, gübreleme, gübreleme+herbisit, tohum ekimi+gübreleme) 3 tekrarlı olarak 30 m2 büyüklüğünde 18 adet parselde uygulanmıştır. Çalışma sonuçlarına göre Odayeri yaylasında gübre (390,0 kg/da) ve herbisit+gübre (325,4 kg/da) uygulamalarından elde edilen kuru ot verimleri, kontrol parseline göre (196,3 kg/da) önemli derecede yüksek bulunmuştur. Elde edilen sonuçlara göre Odayeri yaylası ve benzer ekolojik koşullara sahip yaylalarda gübreleme ve herbisit+gübreleme ıslah yöntemlerinin uygulanabileceği, böylece kuru ot veriminde önemli bir artışın sağlanabileceği düşünülmektedir.Öğe Effect of Land Use on Some Physical and Chemical Water Quality Parameters in the Sub-watersheds of Big Melen Stream(Istanbul Univ-Cerrahpasa, 2022) Çitgez, Tarık; Karagül, Refik; Özcan, Mehmet; Özbayram, Ali KemalThis study was carried out in two watersheds of the Big Melen Stream, which provides water to Istanbul. Forest areas are dominant in the Yukarikarakoy watershed, whereas agricultural areas (hazelnut plantations) are dominant in the Avlayan watershed. There are settlement areas at the outlet regions of both watersheds. The purpose of the study was to compare the effect on the water quality as a consequence of the forests, settlement areas, and hazelnut plantations. Accordingly, pH, electrical conductivity (EC), dissolved oxygen (DO), total nitrogen (TN), NO2-, NO3-, SO42-, PO43-, and NH4+ concentrations were measured in the stream points representing hazelnut plantations, forests, and settlement areas for 2 years. The water quality classification of the sampling points was determined in accordance with the criteria specified in the Turkish Surface Water Quality Regulations (SWQR). The mean EC, TN, NO3-, SO42-, and DO of the sampling point representing the forest were 264 mu S/cm, 1.5 mg/L, 3.1 mg/L, 14.7 mg/L, and 10.3 mg/L, respectively. The mean EC, TN, NO3-, and SO42- values of the point representing the hazelnut plantation were higher than those of the point representing the forest. In the sampling points representing the settlement areas of both watersheds, the EC and PO43- increased, while the DO decreased. As a result, it was determined that the stream water of the point representing the forest was of higher quality than that of the point representing the hazelnut plantation and that the settlement areas significantly reduced the water quality by increasing the concentrations of pollutants.Öğe Effect of rotational grazing on some soil properties in Düzce of Turkey(2017) Özcan, MehmetPastures, one of the four important vegetation types in the world, have great potential not only in terms of forage production for animals, but also in terms of biological diversity. Yet, the pressure of continuous and overgrazing on pastures in Turkey affects both vegetation and soil negatively. Overgrazing leads to soil compaction, thus, soil permeability is influenced in a negative way. It is possible to remove these negative influences via amendment methods or reorganizing grazing. In this study, it was researched how short duration rotational grazing influenced some soil properties in a pasture where uncontrolled heavy grazing for many years in Düzce. As a result of the study, soil properties affected by rotational grazing at most were permeability and bulk density. While the value of bulk density increased from 1.19 gr cm-3 to 1.30 gr cm-3 in the continuous grazing pastures, it decreased from 1.38 gr cm-3 to 1.26 gr cm-3 in the rotational grazing pastures. It was demonstrated in the study that organizing grazing systems in the pastures can improve soil permeability and bulk density to a great extent.Öğe Effect of rotational grazing on some soil properties in Duzce of Turkey(Istanbul Univ, Fac Forestry, 2017) Özcan, MehmetPastures, one of the four important vegetation types in the world, have great potential not only in terms of forage production for animals, but also in terms of biological diversity. Yet, the pressure of continuous and overgrazing on pastures in Turkey affects both vegetation and soil negatively. Overgrazing leads to soil compaction, thus, soil permeability is influenced in a negative way. It is possible to remove these negative influences via amendment methods or reorganizing grazing. In this study, it was researched how short duration rotational grazing influenced some soil properties in a pasture where uncontrolled heavy grazing for many years in Duzce. As a result of the study, soil properties affected by rotational grazing at most were permeability and bulk density. While the value of bulk density increased from 1.19 gr cm(-3) to 1.30 gr cm(-3) in the continuous grazing pastures, it decreased from 1.38 gr cm(-3) to 1.26 gr cm(-3) in the rotational grazing pastures. It was demonstrated in the study that organizing grazing systems in the pastures can improve soil permeability and bulk density to a great extent.Öğe Effect of size and surrounding forest vegetation on chemical properties of soil in forest gaps(Sisef-Soc Italiana Selvicoltura Ecol Forestale, 2015) Özcan, Mehmet; Gökbulak, FerhatForest gaps have different microclimatic conditions as compared to the surrounding areas, depending on gap size and surrounding forest types and affecting the biological, chemical, physical, and hydrological processes in the forest openings. The objective of this study was to determine the effect of forest gap size and surrounding forest cover type (beech or mixed stands) on the soil of forest opening by analyzing several soil chemical soil properties (pH, electrical conductivity -EC, organic matter -OM, and nutrient content). The study was conducted in the Yuvacik watershed in Izmit (Turkey) and a total of 31 forest gaps of different size (1.44-37.33 ha) and elevations (848-1169 m a. s. l.) were studied. Gaps were divided into three groups with size 0-5 ha, 5-15 ha, and > 15 ha. Results showed that forest gap size significantly affected all the investigated chemical properties of the soil, except for soil pH. As gap size increased, sodium (Na+) concentration in the soil decreased from 22.72 to 19.57 mg L-1 while potassium (K+) and magnesium (Mg+2) concentrations increased from 83.88 to 134.62 mg L-1 and from 59.46 to 123.96 mg L-1, respectively. Medium-sized gap soils had the lowest OM content, as well as the lowest calcium (Ca+2) and nitrogen (N+3) concentrations. Surrounding forest types significantly influenced soil chemical properties in the openings, except for EC, N+3, and phosphorus (P-PO4-3). Soils in the gaps surrounded by mixed forest had significantly lower pH but higher OM content, K+, Na+, Ca+2, and Mg+2 concentrations than soils in beech forest gaps.Öğe Effects of some watershed characteristics on water yield in the West Black Sea Region of northern Turkey(Univ Austral Chile, Fac Ciencias Forestales, 2017) Zengin, Hayati; Özcan, Mehmet; Değermenci, Ahmet Salih; Çitgez, TarıkThis paper presents the effect of some watershed characteristics on water yield based on two-year measurements (2015-2016) realized at 29 watersheds. Although, there are several factors affecting the runoffs, we tried to eliminate some and focused on watershed characteristics by choosing the watersheds as near as to each other in the same hydro-climatic zone. These are relatively small watersheds (8.6-449.3 ha) at the mountainous and forested areas around Duzce city, Turkey. Elevation of most watersheds, which is effective on precipitation, is above 1,000 m and covered by snow in winter. Regression models between water yield or runoff coefficient based on water yield/precipitation ratio and some watershed characteristics can be important to estimate the amount of water and manage the forest for its hydrologic function. In this study, the effect of watershed area, form factor, mean slope, drainage density, elevation, circularity and elongation ratios on water yield and runoff coefficient was analyzed by multiple linear regression analyses. While there is not a significant relation between runoff coefficient and watershed characteristics, we constructed a significant regression model for estimating water yield depending on watershed characteristics. Watershed size, elevation, form factor and elongation ratios are found as effective variables on water yield. When other variables (ratio of circularity, mean slope, drainage density) were added, adjusted R-2 and significance of the model was decreased. Results showed that some watershed characteristics have a significant effect on water yield, and equations based on these characteristics can be used in forest management or policy making in determining the priority of watersheds for water production.Öğe Evapotranspiration from a Mixed Deciduous Forest Ecosystem(Springer, 2010) Özhan, Süleyman; Gökbulak, Ferhat; Serengil, Yusuf; Özcan, MehmetThe objectives of this paper were to determine evapotranspiration (ET) from an oak-beech dominated forest ecosystem in Belgrad Forest near Istanbul, Turkey by using catchment water balance method and compare it with potential evapotranspiration (PET) computed by using Thornthwaite method. Data, in this study, were derived from a long-term hydrological research conducted in Belgrad Forest. Long-term stream flow measurements (1979-1995) were conducted with concrete sharp-crested V-notch weirs instrumented with automatic water level recorders in two close experimental watersheds. ET values of the watersheds were determined by using water balance equation. Average annual ET values from the old growth oak-beech forest ecosystem during the monitoring period of 17 years were around 833.20 mm for W-I and 752.07 mm for W-IV whereas PET estimated according to Thornthwaite method was found to be 726.14 mm. In other words, 79.68%, and 71.93% of mean annual precipitation evaporated from W-I and W-IV, respectively while 69.45% of precipitation evaporated according to Thornthwaite method. PET estimated with Thornthwaite method differed significantly only from W-I whereas W-I and W-IV had similar ET values.Öğe EXCLOSURE EFFECTS ON RECOVERY OF SELECTED SOIL PROPERTIES IN A MIXED BROADLEAF FOREST RECREATION SITE(Wiley-Blackwell, 2013) Özcan, Mehmet; Gökbulak, Ferhat; Hızal, AhmetHuman-caused trampling that results from excessive recreational use has caused damage to soil and vegetation in forest ecosystems in the Belgrad Forest of Istanbul. The objectives of this study were to examine effects of exclosure on selected soil properties and to determine the recovery time required for soil characteristics in a broadleaf forest recreation site. Litter biomass and topsoil (0-15cm) were sampled in the forest, exclosure and recreational sites, and soil samples were analysed for saturation capacity, permeability, bulk density, total porosity, organic matter, root biomass, electrical conductivity and soil pH. Results showed that saturation capacity, permeability, total porosity and organic matter increased whereas bulk density decreased significantly in the topsoil under the exclosure, and all these soil properties in the topsoil of the exclosure were greater than those of recreational site. When effects of main factors were compared, averaging over sampling year and soil sampling depth, soils from the exclosure had significantly greater saturation capacity, permeability, total porosity, organic matter and litter biomass and lower bulk density values than the soils from recreational site. Six years of exclosure was effective in improving most of the soil properties in the topsoil. When topsoil and subsoil are considered together, it is obvious that a longer time period is needed for soil recovery in the forest recreational sites. Copyright (c) 2011 John Wiley & Sons, Ltd.Öğe Hydro-physical properties of soils developed from different parent materials(Elsevier, 2008) Gökbulak, Ferhat; Özcan, MehmetThe objectives of this study were to compare some selected hydro-physical properties of soils developed from different parent material under the same climate type, similar topography and vegetation cover and to present significant differences in the soil characteristics with numerical values. For this purpose, five different sites with similar topography, vegetation cover, the same climate type, and different parent materials were selected in the northeast part of Turkey where some studies were previously carried out by scientists from the Faculty of Forestry at Istanbul University. The parent materials in the sites were granite, clayey limestone (upper triassic), clayey limestone (upper cretaceous), neocene, and arkose. Results indicated that all properties studied except for saturation capacity and particle density of soils differed significantly with respect to the parent materials. Compared to other soil types developed from the parent materials, granite formed soils with greater sand and lower silt contents, numerically greater porosity, and significantly higher dispersion ratio and organic matter. on the other hand, soils formed on arkose parent materials had the lowest pH value, numerically the greatest available water content and saturation capacity and organic matter percentage. (c) 2008 Elsevier B.V. All rights reserved.Öğe PLANT DIVERSITY INDICES FOR TROJAN FIR STANDS IN ALADAG REGION OF BOLU(Croatian Forestry Soc, 2022) Erdoğan, Emrah; Zengin, Hayati; Özcan, Mehmet; Değermenci, Ahmet Salih; Aksoy, Necmi640 samples in quadrates of 0.5 x 0.5 m obtained by systematic sampling method were evaluated. Samplings were made in two repetitions in GA (old), GB (young), GC (medium-aged), and GD (irregular) stand types, on north and south aspects. Field studies were carried out in 4 different periods (June, July, August, September) within the vegetation period. 122 plant taxa were determined at the level of species and intraspecific taxa. While 48 of the 122 plant taxa in fir stands were seen only in one of the stands, 41 plant taxa were detected in all stands. 5 taxa were seen only in GA stands, 7 in GB, 15 in GC and 13 only in GD stands, while 8 taxa could not be identified due to the insufficient vegetative and generative organs of the collected samples. The richest stand type in terms of taxa number was determined as the GC stand type with 84 plant taxa, but more individuals per ha were counted in the GA and GD stand types.Öğe PUMICE ADDITION EFFECT ON AVAILABLE WATER CAPACITIES OF SOILS(Parlar Scientific Publications (P S P), 2010) Özcan, Mehmet; Özhan, Süleyman; Gökbulak, FerhatThe objective of this study was to determine if addition of pumice material with two different ratios into various soil textural classes increases the available water capacity of the soils. For this purpose, ground pumice particles (<2 mm diameter) were added into loamy sand, sandy loam, loam, clay loam, and clay soil textural classes with a ratio of 1/4 and 1/2 on weight basis. Experiment was arranged in a completely randomized block design with five replications. Results indicated that pumice addition with a ratio of 1/4 increased available water capacity of loamy sand and clay soils but decreased that of sandy loam, clay loam, and loamy clay soil textural classes compared to control samples. After pumice addition with a ratio of 1/4, available water capacity increased from 2.17 to 8.23% for soil textural class of loamy sand and from 1.81 to 3.74% for the soil textural class of clay. When pumice particles were added with a ratio of 1/2 into the same soils, available water content of loamy sand, sandy loam, loamy clay, and clay soil textural classes was significantly increased but those of clay loam was decreased.Öğe Response of understory vegetation to exclosure in a heavily compacted forest recreational site(Triveni Enterprises, 2013) Oral, Dilek; Özcan, Mehmet; Gökbulak, Ferhat; Efe, Asuman; Hızal, AhmetObjectives of this study were to investigate effect of exclosure on understory vegetation recovery and determine the time required for understory vegetation recovery in a forest recreational site. Recovery of understory vegetation in an exclosure was monitored for three growing seasons and plant density and vegetation cover were determined for each plant species. Exclosure was compared with control plot for the Shannon index of diversity. Results showed that a total of 33 (18 woody, 15 herbaceous) plant taxa were established in the exclosure while 42 (16 woody, 26 herbaceous) were encountered in the forest plot. Quercus petraea (Mattuschka) Liebi. subsp. iberica (Steven ex Bieb.) Krassiln. had the highest density both in the exclosure (30.37 plants m(-2)) and forest plot (25.75 plants m(-2)) and followed by Hedera helix L. (28.44 plants m(-2) in the exclosure, 23.33 plants m-2 in the forest plot). Plant species recovered in the exclosure did not survive very long as growing season progressed, top soil dried, and canopy closure increased. H. helix L. was the major dominant plant species for vegetation cover in both exclosure (45.23 %) and forest plot (45.08 %). There was a significant difference between plots for species diversity and forest plot had diversity index of 1.01 while exclosure had a diversity index of 0.741.
