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Öğe Analysis of activity, space and user relations in urban squares(Sage Publications Ltd, 2020) Acar, Habibe; Yavuz, Aysel; Eroglu, Engin; Acar, Cengiz; Sancar, Cenap; Degermenci, Ahmet SalihWith the increasing density of built spaces in urban areas, the need for open spaces increases every day. Squares are one of the most important of these open spaces. Urban squares allow various activities and exhibit functional differences based on location and culture. The diversity of activities conducted in squares is extremely important for the quality and viability of liveable urban spaces. Urban residents prefer spaces that are suitable for individual requirements and desires and allow for a variety of activities. These spaces also contribute to social life. This article aimed to determine the user profile, occupancy, facilities and activity diversity at the Ataturk Plaza (Trabzon urban square) in Trabzon, the capital city of Trabzon Province, Turkey. The occupants of the square and their numbers were analysed via the behaviour observation method. As a result of the observations conducted in the square over one year, 17 activities were identified. The majority of these activities were necessary activities and that the most common activity was walking. The occupancy density and distribution in the square were analysed using the Geographical Information System (GIS). These research findings and analyses could serve as a guide for future urban square and urban open space designs.Öğe Assessing the Effect of Land Use Changes on Carbon Storage Using Forest Management Plan and Remote Sensing Data(Taylor & Francis Inc, 2025) Degermenci, Ahmet Salih; Ucar, Z.This study evaluated the land use land cover (LULC) classes that were obtained from the forest management plans (FMP) of the Beykoz planning unit and generated from Landsat images for 1992 and 2012. FMPs increased in coniferous forest areas (18.64%) and broadleaved forest areas (1.03%), whereas a decrease (12.79%) was observed in other areas within 20 years. Eight different vegetation indices (VI) obtained from satellite imagery were used for land use classification. The results of the study showed that the RVI had the highest overall accuracy (71%-72%) and kappa value (0.56-0.59) in both study periods. While stored carbon estimated from the FMPs decreased by 46.2% within 20 years due to regeneration of mature forests with clear-cutting, stored carbon assessed from the NDVI map increased by 1.3%. A positive correlation was found for the stored carbon estimated from the FMP and NDVI maps at a rate of 95.2% (R-2=0.90) in 1992 and 54.4% (R-2=0.29) in 2012. Although there was a high correlation between the carbon storage data obtained using the two methods, there was also a significant difference (p < .05). In addition, the effect size was determined to be very large in 1992, and large in 2012.Öğe Determination of land surface temperatures for some oak stands with Landsat 8 OLI satellite images: a case study from Turkey(Springer, 2024) Degermenci, Ahmet Salih; Zengin, HayatiThis study investigates the effect of forest cover, development stage and aspect factors on surface temperature (LST) in Demirk & ouml;y and D & uuml;zce Forest Enterprises (FE) using Landsat 8 OLI satellite imagery from July 2021. In Demirk & ouml;y FE, the highest LST value was recorded in the district center with 47.4 degrees C, in D & uuml;zce FE, the highest LST value was recorded in the provincial center with 44.6 degrees C, while the lowest value was 14.3 degrees C in Demirk & ouml;y FE and 13.02 degrees C in D & uuml;zce FE in densely forested areas. When the stands were evaluated, it was found that pure juvenile oak stands had the highest average LST value with 30.48 degrees C in Demirk & ouml;y FE and 23.96 degrees C in D & uuml;zce FE, whereas lower LST values were observed in old oak stands due to more dense cover. In terms of aspect, higher temperatures were recorded in the southern and western aspects in both study areas. In D & uuml;zce FE, high LST values were also observed in juvenile stands in the northern direction, indicating the influence of local factors such as topography and solar radiation angle. The highest LST values were observed in open forest areas; 6-9 degrees C higher temperatures were found in Demirk & ouml;y and 1-5 degrees C higher in D & uuml;zce compared to vegetated areas. Significant correlations were found between LST and vegetation indices, and the highest correlation was found between LST and Normalized Difference Structuring Index (NDBI) (R2, 0.54 in Demirk & ouml;y and R2, 0.50 in D & uuml;zce). NDVI showed a negative relationship with LST (R2, 0.47 in Demirk & ouml;y, R2, 0.43 in D & uuml;zce). These findings reveal the critical role of forest density, tree species, and forest management practices in regulating surface temperatures, especially in the context of urbanization and deforestation.Öğe Determining plant species diversity of Scots pine stands in the Bolu Aladag region of Turkiye(Univ Austral Chile, Fac Ciencias Forestales, 2023) Gurkan, Mustafa; Zengin, Hayati; Ozcan, Mehmet; Degermenci, Ahmet Salih; Aksoy, NecmiThis study aims to determine how plant diversity changes at the alpha and gamma levels depending on stand type. Also, it tries to understand how plant diversity changes temporally and with relation to aspects during a given vegetation period. Sample areas were selected from pure Scots Pine stands with full canopy cover (70 - 100 %) and in different development stages (a, b, c, d) spread out within the Bolu Aladag region of Turkiye. Field studies were carried out in 2016 from June-September. Sample stands were selected to cover two main aspects, north and south. The study was carried out by analyzing two repetitive and 10 quadrate samples in each stand. A total of 640 quadrate samples were analyzed, and the different plants were counted. In the study area, a total of 160 taxa were identified at the DUOF Herbarium. It was determined that while the stand type did not have a significant effect on taxon diversity, the effect of aspect and observation period was statistically significant (P < 0.05). Shannon index value was between 3.13 and 3.72 among the stands' different development stages, with the highest values found in the young stands. Diversity was higher on Northern aspects than Southern and rose and fell throughout the observation period with the highest values in June and August. Interestingly, while there was no significant effect of stand development stages on taxon diversity, a significant but low correlation has been found between stand diameter and evenness.Öğe Determining the Effect of Green Space Ratio and Urbanization on the Land Surface Temperature, a Case Study in the Istanbul Metropolitan(Pleiades Publishing Ltd, 2024) Degermenci, Ahmet Salih; Zengin, Hayatitudies have shown that the greenspace ratio has a cooling effect on the land surface temperature (LST) in different regions. Sample plots were obtained from 32 different regions in Istanbul. For 1985, 2000, 2013, and 2021, LSTs were determined using Landsat satellite images, and their relationships with GI, NDVI, and NDBI were examined. In the 1985-2021 period, the rate of greenspace in the sample plots decreased from 23 to 6.9%. The lowest LSTs were obtained in 1985, whereas the highest LSTs were found in 2013. Generally, low LSTs values were obtained in areas with a high greenspace ratio. The GI index decreased from 0.23 to 0.07 from 1985-2021. There was an increase of 10.07 degrees C in average LST values in the 1985-2021 period. Negative correlations were found between NDVI and GI indices and LST, and positive correlations were found between NDBI and LST. In 1985, the lowest LST value was obtained in the 31st region with a greenspace ratio of 54%, while in other periods it was 27th region, some of which was covered with forests and the percentage of greenspace ratio decreased from 21 to 11%. The areas with the highest LST values were generally obtained in areas with dense population and urbanization and with a greenspace rate of 1% or less. The DUNCAN test was used to separate regions in terms of LST values.Öğe Investigation of changes in leaf area ındex in different forest stands(Springer, 2025) Degermenci, Ahmet Salih; Zengin, Hayati; Ozcan, Mehmet; Citgez, TarikLeaf area & imath;ndex (LAI) is a fundamental metric of forest canopy structure, driving photosynthetic capacity, carbon sequestration, and ecosystem productivity. In this study, we quantified LAI variation across six forest stand types (pure fir, pure beech, pure Scots pine, mixed coniferous, mixed deciduous, and mixed deciduous-coniferous) and six developmental stages in the D & uuml;zce region of Turkey, an area characterized by mixed, heterogeneous woodlands. Field measurements from 260 systematically distributed sample plots collected in 2015 employed hemispherical photography for LAI, the N-tree method for basal area (BA) and diameter at breast height (DBH), and atmospherically corrected Landsat 8 OLI imagery for NDVI. Descriptive analyses revealed LAI values ranging from 0.36 m(2)/m(2) in pure Scots pine to 6.30 m(2)/m(2) in mixed deciduous stands. One-way ANOVA and Duncan's multiple-range tests confirmed significant differences among stand types (p < 0.01), with mixed and vertically stratified stands exhibiting the highest LAI. Developmental stages showed increasing mean LAI trends from juvenile (ab) to mature (d) classes, though stage-only ANOVA was not significant (p = 0.378) due to high within-stage variability (CV approximate to 31%). Pearson correlations indicated moderate positive relationships between LAI and both DBH (r = 0.49) and BA (r = 0.53), whereas NDVI displayed the strongest association (r = 0.75 overall; up to r = 0.80 in mixed stands). A multiple linear regression model integrating NDVI, DBH, and BA explained 60.6% of LAI variance (F = 129.7, p < 0.001; adjusted R-2 = 0.601), with NDVI emerging as the dominant predictor (standardized beta = 0.683), followed by DBH (beta = 0.326) and BA (beta = 0.187). These findings underscore the complementary value of integrating spectral indices and structural parameters in the estimation of LAI, particularly in heterogeneous forest stands. The structural complexity of mixed stands appears to play a critical role in enhancing canopy development. To improve estimation accuracy in conifer-dominated or high-LAI forests, future studies should consider incorporating alternative vegetation indices and LiDAR-derived structural metrics to overcome limitations such as spectral saturation and insufficient vertical resolution. Such integrated approaches can significantly enhance the scalability and cost-effectiveness of forest health and productivity monitoring efforts.Öğe Multiple linear regression models for the estimation of water flows for forest management and planning in Turkiye(Water Research Commission, 2023) Zengin, Hayati; Ozcan, Mehmet; Degermenci, Ahmet Salih; Citgez, TarikWhile there are many factors, including climatology, geography, topography, vegetation and soil, that affect hydrologic processes, understanding the role of forests seems most essential, due to their manageable nature. In this study, a holistic approach was taken, and possible factors affecting streamflow, including tree, sapling, shrub, herb and soil strata, were measured for 29 small catchments/stream basins located in Turkey. Linear regression models were developed in order to estimate water flow (m3 & BULL;ha-1). Several models were suggested for use in practice. These models were based on the data on hand and displayed a sufficient level of explained variance in the dependent variable. Model 5, based on the variables of catchment area (ha), drainage density, ratio of coniferous stand areas in the catchment (%), tree volume (m3 & BULL;ha-1), leaf area index, number of short saplings (number & BULL;ha-1), and topsoil sand rate (%), was recommended for flow estimation, achieving a 0.73 adjR2 value for test data. These variables can be obtained as part of a survey and water managers can use them to estimate water flow of the catchment. The generated models can be used in multiple-use planning of forests, e.g. in adjusting the volume of stands to get optimum benefit from wood and water production. One of the most interesting results and one that was opposite to that documented in the general literature, was the positive correlation between tree volume and flow per hectare, which suggests a strategy of growing older tree stands to enable greater water production.Öğe Spatio-temporal change analysis and prediction of land use and land cover changes using CA-ANN model(Springer, 2023) Degermenci, Ahmet SalihThe spatial and temporal representation of land use and land cover (LULC) changes helps to understand the interactions between natural habitats and other areas and to plan for sustainability. Research on the models used to determine the spatio-temporal change of LULC and simulation of possible future scenarios provides a perspective for future planning and development strategies. Landsat 5 TM for 1990, Landsat 7 ETM + for 2006, and Landsat 8 OLI for 2022 satellite imageries were used to estimate spatial and temporal variations of transition potentials and future LULC simulation. Independent variables (DEM, slope, and distances to roads and buildings) and the cellular automata-artificial neural network (CA-ANN) model integrated in the MOLUSCE plugin of QGIS were used. The CA-ANN model was used to predict the LULC maps for 2038 and 2054, and the results suggest that artificial surfaces will continue to increase. The Duzce City center's artificial surfaces grew by 100% between 1990 and 2022, from 16.04 to 33.10 km2, and are projected to be 41.13 km2 and 50.32 km2 in 2038 and 2054, respectively. Artificial surfaces, which covered 20% of the study area in 1990, are estimated to cover 64.07% in 2054. If this trend continues, most of the 1st-class agricultural lands may be lost. The study's results can assist local governments in their land management strategies and aid them in planning for the future. The results suggest that policies are necessary to control the expansion of artificial surfaces, ensuring a balanced distribution of land use.
