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    DIVERSITY OF SOIL MICROARTHROPODS IN HABITATS CONTAINING DIFFERENT TREE SPECIES IN THE SPRING SEASON
    (Parlar Scientific Publications (P S P), 2018) Duyar, Ahmet
    This study aims to determine the diversity and community structure of microarthropods in habitats dominated by different tree species. For this purpose, the microarthropod contents of the soil and litter samples collected in May 2017 from habitats dominated by the Arnold/Black pine (Pinus nigra (Arnold)), Oriental beech (Fagus orientalis (Lipsky.)) and Uludag fir (Abies nordmanniana (Stev.) subsp. bornmulleriana (Maid)) tree species were investigated. Soil and litter samples were collected from Arac, Karabuk and Safranbolu forests for Black Pine, Oriental Beech and Fir, respectively. Litter samples used in the extraction of microarthropods were collected using a cylinder of 5 cm diameter and were as thick as the litter cover, while 5 cm thick soil samples were collected from the upper mineral soil to a depth of 5 cm. Moreover, extra samples were collected from the same locations to determine certain physical properties of the litter and soil in those locations. Microarthropods were extracted from the litter and soil samples using the Berlese funnel method and were counted and classified using a microscope. According to the analyses, there were 74 different taxa throughout the three different ecosystems, and there was no statistically significant difference in terms of biological diversity. Based on tree species, the Fir forest had the highest average taxonomic richness (26 taxa), while the Pine forest had the lowest tree species-based taxonomic richness (19 taxa). Similarly, the Shannon's diversity index (H') was the highest in the Fir forest (2.65), while it was the lowest in the Pine forest (2.34). In addition, the litter layer (H' = 2.64) had a significantly higher biological diversity than that in the soil (H' = 2.39). The study is still in progress and any seasonal changes in the relationships will also be revealed with new samples collected during other seasons.
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    THE EFFECTS OF FOREST CANOPY COVER AND ALTITUDE ON SNOW ACCUMULATION AND MELTING IN THE UPPER WATERSHEDS
    (Parlar Scientific Publications (P S P), 2018) Duyar, Ahmet
    A significant amount of water falls down on the ground with snowfall. Therefore, the snow cover accumulated in the upper watersheds can reservoir very large amounts of water. Snow masses may melt at different speeds depending on climate conditions. These reservoirs can regularly feed water resources in slow melting conditions or cause floods with sudden melts. Knowing some of the effective environmental characteristics on the accumulation of snow masses can render possible the estimated amount of water reserves and the extent of flood risks. For this purpose, the snow accumulation and the amount of snow water equivalent at the open area and under the different forest canopies were investigated in the upper watersheds. The selected study area is located in southeast of Bolu province (northwestern Turkey) and consists sampling points on route of Kartalkaya Ski Center (2000 m a.s.l.). In total 11 permanent sample areas were determined between 936 m and 1930 m (a.s.l.) altitudes. Three sampling points were selected as the open area, the semi closed and the fully closed forests at each sample area. The samples were collected three times in a week from December to April. The snow depths (SD) were measured at all sampling points. Snow densities and snow water equivalents (SWE) were determined in the laboratory by using snow core samples taken from the sites. In the evaluation of the samples, Correlation, ANOVA and Duncan analysis were applied to the data, such as independent variables of time, forest cover, altitude and aspect affecting the snow accumulation and dependent variables of SD, SWE and snow density. When the data obtained is evaluated, SD and SWE negatively correlated with forest closures, and positively correlated with altitudes. SD (762 mm) and SWE (170 mm) reached maximum values at open areas in February. Forest canopies significantly reduced the snow accumulations compared to the open areas. The average snow depth was observed in different values within open areas (371 mm), semi closed forests (229 mm) and fully closed forests (165 mm). Similarly, the water equivalent of snow was observed as 86 mm in open areas, 53 mm in semi closed forest, and 38 mm in fully closed forest. Although the snow density did not show a significant difference depending on the forest canopies, it increased based on altitudes and dates (221 g/l in December and 368 g/l in April). The amounts of SD and SWE in open areas were formulated according to altitudes by using the findings. In this way, it is considered that snow accumulation, water reserve and possible water regimes in the upper watersheds can be estimated depending on the snowfall information in a region.
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    The effects of trekking activities on physical soil properties in the Bolu-Aladag fir forests
    (Istanbul Univ, 2018) Duyar, Ahmet; Kinis, Seyfettin
    In this work, we study the effects of trekking on the soil physical properties in the Turkish Bolu-Aladag fir forests. One hundred people walked in a straight line in the case study area, and their effects on a number of soil physical properties, such as litter fall thickness, soil bulk density, soil moisture, and soil compaction, were investigated. The study comprised three replicates over two tracks in two consecutive years. The thickness of the surface litter fall (mm) was measured and its amount determined in (gr/m(2)) as the dry weight of the soil samples collected in the sampling area. Soil bulk density (g/L) was measured using cylindrical samples. Soil moisture (%) was determined based on the difference between the fresh and dry weights. The results indicate that the surface litter thickness decreased on trekking routes (r=0.568), and the fresh (r=0.440) and dried (r=0.423) soil bulk densities increased. However, there appeared to be no effect on soil moisture. Compared to the control samples, an average of 14% compaction was detected in trampled soils as a result of human pressure. Furthermore, the physical effects of trekking caused compaction of the litter fall and soil. As a result, such activities could lead to a decrease in soil infiltration capacity causing soil erosion and degradation in the future.
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    Evaluation of renewable hybrid barriers in terms of carbon emission with concrete and steel barriers
    (Istanbul Univ-Cerrahpasa, 2021) Birinci, Emre; Yorur, Huseyin; Yumrutas, H. Ibrahim; Duyar, Ahmet
    Roadside barriers called as passive safety systems are presently produced from various materials such as steel, concrete, wood, and plastic. Existing roadside barriers have prioritized safety over aesthetics and environmental concerns. To this end, a new environmental barrier-the renewable hybrid barrier (RHB)-has been designed that can fulfill safety requirements as well as add value in terms of aesthetics. Sand is placed inside the barrier, and the barrier's outer shell is covered by fir timber. A life cycle analysis was completed to ensure the sustainable production of RHBsand to better understand their environmental impacts. The amount of greenhouse gas emitted into nature during the production of RHB and steel and concrete barriers was calculated and compared. Our results showed that concrete and steel barrier production releases approximately 4.5 times more greenhouse gases than RHB production. The live biomass equivalent of the wood materials used in RHB production was also calculated. We found that RHBs sequestrated 45.94 kg-CO(2)eq. It is thought that more widespread use of RHBs can contribute positively to the environment and nature.
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    Karabük yöresinde farklı arazi kullanımı ve mevsimlerin karşılaştırılmasında sıçrar kuyrukluların (collembola: arthropoda) biyolojik gösterge olarak kullanımı
    (2020) Duyar, Ahmet
    Farklı arazi kullanımı ve mevsimsel şartlar, toprak özellikleri ve toprak kalitesi üzerinde etkili faktörlerdendir. Toprak kalitesi ölçütlerinden biyolojik göstergelerin kullanımı gün geçtikçe artmaktadır. Burada sunulan çalışmada, biyolojik göstergeler ile farklı arazi kullanımı ve mevsimin toprak biyolojik kalitesine etkisini ortaya koyulması amaçlanmıştır. Çalışmada, topraktaki Collembola miktar ve çeşitliliği ile QBS-c (Collembolalara dayalı biyolojik toprak kalitesi) indeksi kullanılmıştır. Örnekleme, ağaçlandırılmış alan, çalılık, doğal çayır ve işlenmiş topraktan dört mevsimde 3 tekerrürlü olarak yapılmıştır. Her bir alandan 5x5 cm boyutlarındaki silindirlerle toprak örnekleri alınarak ekstrakt edilmiştir. Örneklerdeki Collembolalar familya düzeyinde sınıflandırılmıştır. Collembolalar hem miktar ve biyolojik çeşitlilik bakımından hem de ekolojik morfolojik özelliklerine bağlı olarak QBS-c indeksi bakımından değerlendirilmiş ve istatistiki analizler yapılmıştır. Araştırmanın sonucunda, çalışma alanında tüm arazi kullanım türlerinin yıllık ortalaması olarak 12853 birey/m² Collembola bulunmuştur. Collembola miktar ve biyoçeşitliliği üzerinde farklı arazi kullanımının etkili olmadığı tespit edilmiştir. Fakat, mevsimler arasında önemli bir farklılık olduğu belirlenmiştir. Ortalama Collembola miktarı bahar ve güz mevsiminde (20.500 birey/m²) en yüksek, yazın ise (2761 birey/m²) en düşük bulunmuştur. QBS-c indeks değerleri farklı arazi kullanımı arasında benzer olmasına rağmen, mevsimsel olarak farklılıklar göstermiştir. Bu çalışmada, QBS-c indeksi değeri ile Collembolaların miktar ve biyoçeşitlilik değerleri toprak kalite göstergesi olarak benzer sonuçlar vermiştir ve birbirlerinin yerine kullanılabilir niteliktedir. QBS-c indeksi örnek içerisindeki tüm bireyleri saymayı gerektirmeyen daha kolay bir yöntem olduğundan, pratik uygulamalar için önerilebilir.
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    Use of UAV Data and HEC-RAS Model for Dimensioning of Hydraulic Structures on Forest Roads
    (Zagreb Univ, Fac Forestry, 2023) Acil, Ahmet; Aydin, Abdurrahim; Eker, Remzi; Duyar, Ahmet
    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 Turkiye, 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 Turkiye 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 Acisu Forest Enterprise, Gerede Forest Directorate (Bolu, Turkiye) 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, Kursteiner, 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 Kursteiner 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.