Nikolaos Georgios Oikonomakis

Dr. Nikolaos Georgios Oikonomakis

Forestry and natural environment, Aristotle University, Thessaloníki, Kentrikí Makedonía, Greece
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Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2012 in Forest Ecology and Management
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Journal Article
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NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
PGPetros Ganatsas
Petros Ganatsas

16 November 2020 in Forest Systems
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Journal Article
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NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
PGPetros Ganatsas
Petros Ganatsas
Aim of the study: To investigate the secondary forest succession in the study area and the pathways of its spread and the existing environmental, autecological factors and possible inter-specific competition relationships.Area of study: The study area is a Site of Natura 2000 network in northern Greece dominated by two pioneer forest species, Betula pendula and Pinus sylvestris. Study area is the southern limit of Silver birch in Europe and genotypes of these forests may be important due to the anticipated global increase of temperature and the forthcoming climate change.Materials and methods: The main forest types studied were: pure forests of B. pendula and P. sylvestris and mixed forests of these two main species. To study the expansion of forests in the area, a spatial analysis was performed based on geographical data. To detect forest changes, the rate thereof and their specific spatial distribution and preferences, a statistical analysis was performed.Main results: Approximately 60% of the studied area in 1945 was transformed from grasslands/barelands to forests. The composition of new forests was found to be different from the old ones. The rate of forest establishment in the first years was lower than in the latter years. All factors examined played an important role to the expansion of forest exept slope.Research highlights: Distance from the old stands played the most determining role to new forest structure and composition. Inter-specific competition results to the formation of pure stands, as indicated by the older stands.Keywords: secondary forest succession; Betula pendula; GIS; spatial analysis; forest species competition; forest species distribution.

11 March 2022 in Ecological Engineering
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Journal Article
Closed access
PGP. Ganatsas
P. Ganatsas
MTM. Tsakaldimi
M. Tsakaldimi
NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
MDM. Davis
M. Davis
CMC. Manios
C. Manios
CBC. Broumpas
C. Broumpas

1 October 2022 in Fire
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Journal Article
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PGPetros Ganatsas
Petros Ganatsas
NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
Marianthi TsakaldimiMarianthi Tsakaldimi
Marianthi Tsakaldimi
In the past few years, the continuous expansion of urban development has created mixed forested, agricultural, and urban areas. These areas are called the wildland–urban interface (WUI), and they are characterized by increased human activities and land-use conversion, and they usually contribute to a high risk of wildfire occurrence. In the case of the peri-urban areas of Thessaloniki city, an effort was made to map, classify, and describe this wildland–urban interface, using Sentinel-2 satellite images of the area and very large scale orthophotos (VLSO) for the human settlements. Object-based image analysis (OBIA) was applied to classify landcover, combined with analysis of field data. The results showed that the WUI area in the city of Thessaloniki appears to the north and east of the city and covers an area of 2203.98 ha. The main characteristics affected by the ecological conditions of this area are the building (or human infrastructure) density, type, and the structure of forest vegetation. Human population pressure was found to be greatly differentiated between WUI areas belonging to different municipalities, the most affected was the municipality of Thessaloniki. A set of fire prevention silvicultural treatments are suggested for mitigating the fire danger in the area, accompanied by appropriate human awareness actions and the involvement of the local society. These measures include the reduction in crown bulk density and increase in crown base height through pruning (at least to 1/3 of total tree height), and low thinning, aiming to ensure that tree crowns of mature Pinus brutia trees are not in contact with one another. Both in the young P. brutia forest and the evergreen vegetation areas, thinning, pruning, and vegetation clearing is recommended adjusted according to each ecosystem.

8 April 2014 in International Journal of Remote Sensing
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Journal Article
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Thomas AlexandridisThomas Alexandridis
Thomas Alexandridis
NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
Ioannis Z. GitasIoannis Z. Gitas
Ioannis Z. Gitas
KEK.M. Eskridge
K.M. Eskridge
NSN.G. Silleos
N.G. Silleos
Vegetation monitoring has been performed using remotely sensed images to secure food production, prevent fires, and protect natural ecosystems. Recent satellite sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS), provide frequent wide-scale coverage in multiple areas of the spectrum, allowing the estimation of a wide range of specialized vegetation indices (VIs), each offering several advantages. It is not, however, clear which VI performs better during operational monitoring of wide-scale vegetation patches, such as CORINE Land Cover (CLC) classes. The aim of this work was to investigate the performance of several VIs in operational monitoring of vegetation condition of CLC vegetation types, using Terra MODIS data. Comparison among the VIs within each CLC class was conducted using the sensitivity ratio, a statistical measure that has not been used to compare VIs and does not require calibration curves between each VI and a biophysical parameter. In addition, the VI’s sensitivity to factors such as the aspect, viewing angle, signal saturation, and partial cloud cover was estimated with correlation analysis in order to identify their operational monitoring ability. Results indicate the enhanced vegetation index as superior for monitoring vegetation condition among CLC types, but not always optimum in performance tests for operational monitoring.

5 March 2026 in Genes
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Evangelia V. AvramidouEvangelia V. Avramidou
Evangelia V. Avramidou
Evangelia KorakakiEvangelia Korakaki
Evangelia Korakaki
NONikolaos Georgios Oikonomakis
Nikolaos Georgios Oikonomakis
Miltiadis AthanasiouMiltiadis Athanasiou
Miltiadis Athanasiou
Background/Objectives: Fire is a dominant ecological force in Mediterranean ecosystems, shaping the adaptive traits of forest species such as Pinus brutia. Prescribed burning (also called controlled burning) is the intentional, carefully planned use of fire under specific environmental conditions to manage vegetation and reduce wildfire risk. While morphological and physiological fire adaptations are well-documented, emerging evidence highlights the role of epigenetic mechanisms—such as DNA methylation and histone modifications—in mediating stress responses. Methods: This study investigates genome-wide epigenetic changes in P. brutia following a prescribed burning experiment on Chios Island, Greece. Using methylation-sensitive amplified polymorphism (MSAP) analysis, we compared temporal shifts on epigenetic profiles before and after fire exposure extracting DNA from the same trees. Results: A significant increase in polymorphic epiloci, epigenetic diversity indices, and private epigenetic bands after prescribed burning was revealed, suggesting a stress-induced reprogramming of the epigenome. Concurrent measurements of midday needle water potential indicated an exploratory association between water stress and epigenetic shifts. Furthermore, Fireline Intensity (FI) correlated with epigenetic diversity index signaling an immediate response of the tree. Conclusions: These findings support the hypothesis that fire stress induces epigenetic responses in P. brutia, potentially enhancing resilience to future environmental challenges. Further research is required to address the level of heritability of these epigenetic changes in next generation and connect these indexes with adaptation and sustainability of forest ecosystems.