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Analysis of temporal changes in land cover and landscape metrics of a managed forest in the west Black Sea region of northern Turkey: 1970-2010
(Northeast Forestry Univ, 2018) Zengin, Hayati; Değermenci, Ahmet Salih; Bettinger, Pete
Forest structure changes continuously by natural and anthropogenic effects. Because the level of goods and services provided by forest ecosystems are related to this structure, some attributes have to be controlled while they are being managed. In this paper we describe the long-term temporal changes in land area and landscape metrics related to different land uses of a managed forest in Turkey. The study was carried out for the Daday Forest Planning Unit located in the west Black Sea region of northern Turkey. The total area is 16,813 ha and besides wood production, it is managed for erosion control, public health, aesthetics, and recreation. Stand type maps that were constructed in 1970, 1989, 1999, and 2010 were used in this analysis. Transition matrixes that illustrate area changes among cover types and temporal changes on some landscape metrics were obtained using Geographic Information Systems. Stands were separated into small patches, and thus the number of patches increased nearly two-fold between 1970 and 2010. The total forest edge increased and through the associated fragmentation, the amount of core forest area decreased at the landscape scale. Landscape metrics were applied to digitized versions of historical maps to assess how forest area changed. Human use of the land has changed, forest management practices have evolved, and these along with natural forest growth have contributed to interesting changes in landscape character.
Bolu ili arazi kullanım sınıflarına göre toprak üstü biyokütlede depolanan karbon miktarlarının NDVI ile belirlenmesi
(2023) Değermenci, Ahmet Salih; Zengin, Hayati
Bu çalışmada Bolu ili 1990, 2006 ve 2018 yılları arazi sınıfı durumları ve dönemler arası arazi sınıfı geçişleri incelenmiştir. Ayrıca 1990-2018 yılları için arazi kullanım sınıfları toprak üstü biyokütlelerinde (TÜB) depolanan karbon miktarları NDVI uydu görüntüleri üzerinden belirlenmiştir. Arazi sınıflarının değişimini belirlemek için CORINE arazi sınıflandırması kullanılmıştır. 1990 ve 2018 yıllarında karbon depolama miktarlarını belirlemek için Landsat 5 TM ve Landsat 8 OLI uydu görüntüleri kullanılmıştır. Arazi sınıflarından yapay yüzeylerde 28 yıllık süreçte yaklaşık %81.56’lık artış olmuştur. Tarım alanlarında ise toplamda %2.87 (5539.8 ha) oranında artış yaşanmıştır. Orman ve yarı doğal alanlar ise aynı dönemde %1.83 (11745.5 ha) oranında azalmıştır. 28 yıllık süreçte su kütlesi alanları ise yaklaşık 3.4 kat artmıştır. Arazi sınıfı AGB’deki karbon miktarları bakımından 28 yıllık süreçte yaklaşık %59.5 karbon birikmesi olmuştur. 1990 yılında Arazi sınıfları AGB’sinde toplam 1583467.3 ton karbon depo edilmişken, 2018 yılında bu miktar 2664549.5 ton karbona yükselmiştir. 1990 yılında depolanan toplam karbonun %82.5’i orman alanlarında ve % 17’si de tarım alanlarında depolanmıştır. 2018 yılında ise toplam karbonun %76.3’ü orman ve yarı doğal alanlarda, %23’ü de tarım alanlarında depolanmıştır. Bu 28 yıllık süreçte, farklı bir arazi sınıfına dönüştürülmemiş arazi kullanım/arazi örtüsü sınıflarının TÜB'lerinde toplam 1000151.7 ton karbon birikmiştir. Dönüşüme uğrayan araziler üzerinden de toplam 80930.6 ton karbon bir arazi sınıfından diğerine taşınmıştır. Toplamda 1990-2018 yılları arasında 1081082.3 ton karbon birikimi meydana gelmiştir.
Determination of temporal changes in land uses in Hasanlar Dam basin
(Istanbul Univ, 2018) Zengin, Hayati; Özdemir, Hakan Yasin; Değermenci, Ahmet Salih
The impact of human activities on nature is increasing day by day along with changing patterns of land use. These changes also influence the level of the expected function of natural ecosystems. Therefore, for the purposes of meeting the needs of a growing population for ecosystem services at optimal levels, it is important to understand and control the factors that affect land use and to control the changes in land use according to the objectives. The aims of this study were to determine land-use patterns in Hasanlar Dam basin per period, analyze the temporal changes in land use according to area, and determine the reasons for the changes in the basin by digitizing the maps of the basin area belonging to the period between 1986 and 2010. Forest land-use patterns were categorized into the following six groups: forest, (deciduous, coniferous, mixed, and degraded), forest gaps, hazelnut, agriculture, pasture, and other areas. The forest area that was 64,843 ha in 1986 had declined to 62,709 ha in 2010. Hazelnut areas covering an area of 3,636 ha in 1986 were represented as agricultural areas in the 2010 stand maps. The agricultural areas that were 8,925 ha in 1986 increased to 15,420 ha in 2010. The pasture areas comprising 267 ha in 1986 decreased to 19 ha in 2010. Other areas decreased from 1,302 ha to 825 ha between 1986 and 2010. Through the Melen project, water is being transported to Istanbul from Hasanlar Dam. Therefore, since changes in the land-use pattern in the Hasanlar Dam basin may affect both water efficiency hydrologically and the quality of water, it is necessary to monitor the changes in forest, agriculture, pasture, forest soil, and other areas and also the changes in the demographic structure. In addition, it must be ensured that these changes cause the minimum impact on water yield and quality.
Determining the effects of changes in land use on carbon storage in above-ground biomass with NDVI
(Global Network Environmental Science & Technology, 2023) Değermenci, Ahmet Salih
In terms of sustainable land use management, it is extremely important to reveal the land conditions and the changes that occur on the land in certain periods. In this study, using CORINE data for Duzce province, land use status and transitions between land-use classes over 28 years were investigated. In addition, changes in carbon storage in above-ground biomass were determined for each land-use and land transition using Landsat satellite images for the years 1990 and 2018. 28 years, artificial surfaces increased from 3,852 hectares to 9,058 hectares. While agricultural areas increased by 11.5% to 114,650 hectares, forest and semi-natural areas decreased by 14% to 122,955 hectares. 96.7% of the increase in agricultural areas was land converted from forest areas. While the amount of carbon stored in the forest and semi-natural areas increased by 27.9%, it increased by 30.5% in agricultural areas. With land transitions, 17.8% of the total carbon (14,407 tons) was transferred from one land use to another. In terms of annual land-use change rate between 1990 and 2018, the highest rate of land-use change was in the post-earthquake 2000-2006 period. The information in this study will make important contributions to policymakers in land management and planning.
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, Tarık
This 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.
Evaluating the Accuracy of Remote Dendrometers in Tree Diameter Measurements at Breast Height
(Zagreb Univ, Fac Forestry, 2022) Uçar, Zennure; Değermenci, Ahmet Salih; Zengin, Hayati; Bettinger, Pete
An accurate tree diameter (DBH) measurement is a significant component of forest inventory. This study assessed the reliability of remote dendrometers to measure tree DBH. We compared direct caliper measurements (reference measurements) to the remote measurements collected from a laser caliper and a smartphone at 0.5 m, 1 m, and 1.5 m distances from each tree within three forest types (pine, oak, and poplar forests). In general, all remote dendrometers underestimated the mean diameter compared to direct caliper measurements, regardless of forest types and distances. We observed that the mean deviation of direct caliper measurement and smartphone measurement at 1.5 m within a pine forest and oak forest were the lowest (0.3 cm and 0.36 cm, respectively). The deviations between direct caliper measurements and smartphone measurements at a 0.5 m distance, across forest types, were noticeably larger compared to others. An ANOVA test was used to determine whether significant deviations existed between caliper measurements and remote measurements at a specific distance, and among three different forest types. We rejected the null hypothesis, which suggested that there were no statistically significant differences (p<0.05) between tree DBH measurements obtained from the direct caliper measurements and indirect measurements (smartphone and laser caliper) captured at a distance. Then, a post-hoc test was performed to examine which set of estimated deviations was different from the reference data. The results suggested that indirect tree DBH measurements using the smartphone app at 1 m and 1.5 m in certain forest types (pine and oak) were not significantly different from direct tree DBH measurements. Also, our test results mostly indicated no significant difference within each forest, except for measurements using the smartphone app at 0.5 m across all forest types when the smartphone measurements were compared to laser caliper measurements. Although forest characteristics and measurement distance may play an important role in remote tree DBH measurement accuracy, the smartphone app may be used as a practical alternative to direct measurement in measuring the DBH of a tree, which may be a positive development for forestry due to the increased use of smartphones and the availability of a free measure app.
Evaluation of forest management plans in conjunction with the cadastral information: The case of Agva and Beykoz, Istanbul
(Istanbul Univ, Fac Forestry, 2016) Çakır, Günay; Güler, Alptuğ; Zengin, Hayati; Değermenci, Ahmet Salih
Determination of land ownership and boundaries is one of the most important purposes of the urban and rural land laws. There can be some boundary problems while preparing forestry area of any urban area when there is not consistency between the borders constructed by different state organizations like land cadastre, forest cadastre and forest management and planning teams. This study aims to illustrate these conflicts in forestry applications process of two different areas (Agva and Beykoz) having different characteristics. The study was carried out in Agva and Beykoz districts in the province of Istanbul and focused on the integration in the land and forest cadastral systems. The Beykoz and Agva Forest Planning Units have different characteristics in terms of population (urban and rural) and social impacts. Analyses of the data obtained from the field studies which it was utilized for the investigation of the data obtained from various base maps, were carried out using GIS software. Many inhabitants of the villages in the Agva Planning Unit had migrated from the district. Thus, in accordance with Boundary Law number of 6831 part of 2/B some parcels of villages in Agva were determined to be acting forest and were reassigned as forest land. In Beykoz, however, areas of this nature were few and the destruction of the forests was great. The spatial analysis of the study made it possible to remove discrepancies occurring in the cadastral situation by preparing forest management plans. Consequently, if land cadastre and forest cadastre units carry out work in coordination to determine the cadastral situation, a basis for forest management plans can be established and cadastral problems greatly reduced.
A GIS-BASED DECISION SUPPORT SYSTEM FOR FOREST MANAGEMENT PLANS IN TURKEY
(Gh Asachi Technical Univ Iasi, 2010) Sivrikaya, Fatih; Başkent, Emin Zeki; Şevik, Uğur; Akgül, Caner; Kadıoğulları, Ali İhsan; Değermenci, Ahmet Salih
This study is designed to develop a Geographic Information System (GIS) based contemporary forest management planning model (ETCAPKlasik) enabling to embrace the features of forest management planning guidelines. The model is implemented at a forest management unit level for even-age, uneven-age and coppice forests. The model has four modules as Data Input with inventory compilation, Harvest Scheduler with classical approach and Data Output as reporting and mapping with GIS functionalities. The model has been successfully tested on a case study site in Kizilcasu planning unit in Turkey. The results showed that ETCAPKlasik model easily compiled the sampling data from field inventory and mapped the results of plan (forest stratification, age class and site maps etc.). Harvest scheduling was conducted according to even-age and uneven-age planning methods. The outputs are generated according to the management guidelines. In conclusion, the model has contributed to the forest management process with the help of information technologies enabling the process to be faster, sound and timely using relatively less amount of time and labor. ETCAKlasik has the potential for use in preparing contemporary forest management planning process.
Meşcerelerin gençleştirme ve bakım düzeninin su miktar ve kalitesi açısından optimize edilmesi
(Düzce Üniversitesi, 2018) Değermenci, Ahmet Salih; Zengin, Hayati
Ormanlar genellikle yüksek dağlık kesimlerde dağılış göstermekte ve ormanları oluşturan havzalar içme suyu başta olmak üzere insan ihtiyaçları için pek çok alanda kullanılan suyun temel kaynağını oluşturmaktadır. Ormana yapılacak müdahaleler bu havzalardan elde edilecek olan suyun miktarını, kalitesini, karbon birikim değerlerini ve elde edilecek gelirleri de etkilemektedir. Bu nedenle düzenlenecek kesim planlarının uzun süreçli tahmini için, ormanların sunduğu diğer fonksiyonlara yönelik bilgi eksikliklerinin giderilmesi ve orman dinamikleri ile ilişkilerinin sayısal olarak ortaya konulması gerekmektedir. Bu temel altlık verilerin elde edilmesi için de disiplinler arası çalışmaların yapılması gerekmektedir. Bu amaçla iki aşamalı olan bu tez çalışmasının ilk aşamasında Tübitak projesi kapsamında havza karakteristikleri ile orman yapısı arasındaki ilişkiler ortaya konulmaya çalışılmıştır. Elde edilen verilerden ve ilişkilerden sonra örnek bir planlama birimi seçilerek, o planlama birimi için planlama modelinin geliştirilmesi ve farklı amaç fonksiyonlarına yönelik modelden elde edilen çözümlerin uzun dönemli karşılaştırılması hedeflenmiştir. Tüm ormancılık fonksiyonlarının modele entegrasyonu bilgi eksikliklerinden dolayı çok zordur. Bu nedenle bu çalışma kapsamında orman fonksiyonlarından odun üretiminin yanı sıra hidrolojik fonksiyon ve ormanların karbon birikim fonksiyonunun bir planlama yörüngesi boyunca, farklı amaç fonksiyonları ve farklı kısıtlara göre nasıl değişimler gösterdiği, nasıl bir kesim planı düzeni oluşturulduğu anlaşılmaya çalışılmıştır. Planlama tekniği olarak Karışık Tamsayı Programlama Tekniği kullanılmıştır. Optimizasyon modelinin koşturulmasında ve çözümlerin elde edilmesinde GAMS yazılımından faydalanılmıştır. Planlama birimi için yedi farklı planlama stratejisi geliştirilmiş ve bu farklı stratejilere göre kârın maksimize edilmesi amaçlanmıştır. Geliştirilen stratejilerden en yüksek amaç fonksiyonu değeri optimal periyodik alan kısıtının olmadığı stratejide elde edilmiştir. En yüksek su miktarının elde edildiği strateji ise gençleştirilecek alan miktarına yönelik kısıtın olduğu strateji de gerçekleşmiştir. Bağlanan karbon miktarları planlama stratejilerinin çoğunda gençleştirilen alan miktarlarının yüksek olması sebebiyle azalırken, sadece periyodik gençleştirme kısıtı olan stratejide tüm periyotlarda artış göstermiştir. Planlama yörüngesi sonundaki dikili servet miktarları sadece gençleştirme kısıtının olduğu ST7 planlama stratejisinde artmıştır diğer stratejilerde azalmıştır.
MODELING HARVEST SCHEDULING IN MULTIFUNCTIONAL PLANNING OF FORESTS FOR LONGTERM WATER YIELD OPTIMIZATION
(Wiley-Blackwell, 2015) Zengin, Hayati; Asan, Ünal; Destan, Sinan; Ünal, Murat Engin; Yeşil, Ahmet; Bettinger, Pete; Değermenci, Ahmet Salih
In this study, wood production and hydrologic functions of forests were accommodated within a planning procedure for separate working circles (areas dedicated to certain forest functions) that were delineated according to an Ecosystem-Based Functional Planning approach. Mixed integer goal programming was used as the optimization technique. The timing and scheduling of a maintenance cutting (partial harvest) was the decision variable in the modeling effort, and an original formulation was developed as a multiobjective planning procedure. Four sample planning strategies were developed and model outputs were evaluated according to these strategies. Spatial characteristics of stands were considered, and used to prohibit the regeneration of adjacent stands during the same time period. Because of the positive relationship between qualified water production and standing timber volume in the forest, the model attempts to maximize qualified water production levels by increasing standing volume stocks in the forest through the delay of regeneration activities.
Optimization of water yield, carbon storage and wood production in forest planning by mixed integer programming
(Univ Austral Chile, Fac Ciencias Forestales, 2022) Değermenci, Ahmet Salih; Zengin, Hayati; Ünal, Murat Engin
Interventions to the forest also affect the amount and quality of water and carbon storage; revenues to be obtained from these areas as well. Therefore, for the long-term estimation of the harvest plans to be organized, it is necessary to eliminate the lack of information for other functions provided by the forests and to quantify their relationship with forest dynamics. In this study, it was intended to determine how forest functions, such as wood production, hydrologic and carbon storage functions, changed according to different objective functions and constraints and what kind of harvest scheduling is prepared in line with a planning process. Seven different planning strategies have been developed for the Cicekli planning unit, aimed at maximizing profit according to these different strategies. Among the developed strategies, the highest objective function value (500,704,847 TL) was obtained in the strategy 6 (ST6), where there is no Optimal Periodic Area (OPA) constraints. The highest amount of water (894,728,400 m(3)) was obtained in the strategy 7 (ST7), which has a constraint on the amount of area to be regenerated. While the amount of carbon stored in the planning unit decreased due to the high amount of regenerated area in most planning strategies, only in ST7 it has increased in all periods, showing periodic regeneration constraints. At the end of the planning horizon, the amount of growing stock (2,446,402 m(3)) has increased only in ST7 with regeneration constraints, whereas the amount of growing stock has decreased in all other strategies.
Orman amenajman planlarıyla kadastro bilgilerinin birliktedeğerlendirilmesi: Ağva ve Beykoz Örneği
(2016) Çakır, Günay; Güler, Alptuğ; Zengin, Hayati; Değermenci, Ahmet Salih
Kentsel ve kırsal alanda arazi hukunun en önemli amaçlarından birisi arazilere ait mülkiyet ve sınırlarının doğru belirlenmesidir. Yerleşim alanlarına sınır teşkil eden ormanların kadastro haritalarının hazırlanmasındaki bazı problemler; genel arazi kadastrosu, orman kadastrosu ve orman amenajman ekipleri tarafından yapılan çalışmaların tutarsızlıklarından kaynaklanır. Bu çalışmada iki farklı özelliğe sahip (Ağva ve Beykoz) bölgede orman amenajman planlaması ve kadastral durumlar arasında oluşan çelişkileri belirlemek amaçlanmıştır. İstanbul İli Ağva ve Beykoz ilçelerinde gerçekleştirilen çalışmalar sonucunda genel arazi kadastrosu, orman kadastrosu ve orman amenajman planı verileri karşılaştırılmıştır. Beykoz ve Ağva Orman İşletme Üniteleri, sosyal (nüfus, kent ve kırsal) ve arazi kullanımı yönünden farklı özelliklere sahip alanlardır. Arazi çalışmaları ve altlık haritalardan sağlanan verilerin analizleri Coğrafi Bilgi Sistemleri (CBS) yazılımıyla sağlanmıştır. Ağva Orman İşletme Ünitesinde köylerden kente göç olmuştur. Bu nedenle 6831 Sayılı Orman Kanunu'nun 2B maddesine göre Ağva'daki köylere ait bazı parseller eylemli orman arazisi olarak ayrılmıştır. Beykoz'da sosyal özellikler sonucunda ormanların tahribi ise fazla olduğu görülmüştür. Çalışmada farklı kadastral verilerin eşzamanlı değerlendirilmesi ve CBS ortamında uygulanan konumsal analizlerle uyumsuzluklar giderilmiştir. Sonuç olarak, kadastral (mülkiyet) durumunun belirlenmesinde genel ve orman kadastro ekiplerinin birlikte çalışması, mülkiyete konu olan problemleri büyük ölçüde azaltmış ve orman amenajman planları için sağlam altlıklar oluşturmuştur.
Ormanlardaki karbon birikiminin konumsal ve zamansal değişiminin incelenmesi: Daday planlama birimi örneği
(2016) Değermenci, Ahmet Salih; Zengin, Hayati
Artan ve çeşitlenen doğal kaynaklara talebin karşılanmasına yönelik olarak orman ekosistemlerinin kapasitelerinin zorlanarak tahrip edilmesi, biyolojik çeşitliliğin azalması, kirlilik ve küresel ısınma gibi pek çok sorunun ortaya çıkmasına neden olmuştur. Küresel ısınmanın sebebi olarak sanayileşme ve arazi kullanım değişiklikleri sonucu atmosfere salınan CO2 miktarının artması gösterilmektedir. Orman ekosistemleri karbon havuzudur ve küresel ısınmanın etkisinin azaltılmasına önemli katkı yapmaktadır. Bu nedenle, orman ekosistemlerinde depolanan karbon miktarının değişiminin belirlenmesine yönelik çalışmalar son dönemlerde yaygınlaşmıştır. Bu çalışma kapsamında, Daday planlama biriminin 1970, 1990, 1999 ve 2012 yıllarına ait toprak üstü ve toprak altı biyokütleye bağlı karbon depolama kapasitesinin zamansal ve konumsal olarak nasıl bir değişim gösterdiği, ArcGIS 10.2TM yazılımı kullanılarak belirlenmiş ve karbon depolama haritaları oluşturulmuştur. 1970 ve 2012 yılları arasında karbon miktarının yaklaşık 871 bin ton, biyokütle miktarının da yaklaşık 1.1 milyon m3 arttığı görülmüştür. Yıllara ait değerler incelendiğinde özellikle verimli ormanlardaki biyokütle ve karbon birikimi miktarlarında gözle görülür bir artış olduğu belirlenmiştir. Biyokütle ve karbon birikimindeki bu artışlar bozuk orman alanlarının azalması ve verimli orman alanlarının artmasından kaynaklanmaktadır.
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, Necmi
640 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.

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