Milan Koreň

• PhD
• Professor (Associate) at Technical University of Zvolen

Global warming plays a major role in the disruption of forest ecosystems by bark beetle outbreaks. Decreasing precipitation and more frequent droughts create the conditions for water stress in trees. The Eurasian spruce bark beetle (Ips typographus L.) is more dangerous for Norway spruce (Picea abies (L.) Karst.) forests in Central Europe under the...

Terrestrial laser scanning (TLS) is used for the acquisition of precise data from forest areas and their environment, offering a comprehensive three-dimensional (3D) representation of trees through point clouds. The primary aim of this investigation is to partition the layers of the forest, delineating trees and the understory within the complex fo...

The compelling role of tree identification and measurement spans ecological and socioeconomic domains and emphasizes its importance for environmental studies and forest management. The accuracy of tree detection and parameter estimation is crucial, which has led to the use of advanced technological methods in recent research. In this study, geometr...

GNSS/INS-based positioning must be revised for forest mapping, especially inside the forest. This study deals with the issue of the processability of GNSS/INS-positioned MLS data collected in the forest environment. GNSS time-based point clustering processed the misaligned MLS point clouds collected from skid trails under a forest canopy. The point...

This study focused on trends and driving forces of the leaf unfolding (LU) onset of oak and beech forests in the Slovak Carpathians along elevational gradients in the period 2000-2021. Particular attention was paid to improving the modelling of the LU onset using the MOD/MYD09 Moderate Resolution Imaging Spectroradiometer (MODIS) products. The LU o...

Global warming plays the main role in disturbances in forest ecosystems by the bark beetle outbreaks. Decreasing precipitation and increase in the frequency of drought periods create conditions for the water stress of trees. The European Spruce Bark Beetle (Ips typographus L.) is a more dangerous pest for Norway spruce (Picea abies (L.) Karst.) for...

The main objective of this research was to develop a web-based geographic information system (GIS) based on a detailed analysis of user preferences from the perspective of forest research, management and education. An anonymous questionnaire was used to elicit user preferences for a hardware platform and evaluations of web-mapping applications, geo...

OPTIMIZATION OF FELLED TRAP TREES FOR BARK BEETLES CONTROL

Long periods of drought and mild winters have significantly affected the forests of the Czech Republic in recent years. If this trend continues, forest stands will be weakened and dehydrated, which will increase the probability that forest fires will occur and spread. It is essential that fire managers prepare for this possibility. A main requireme...

Machine learning algorithms (MLAs) are used to solve complex non-linear and high-dimensional problems. The objective of this study was to identify the MLA that generates an accurate spatial distribution model of bark beetle (Ips typographus L.) infestation spots. We first evaluated the performance of 2 linear (logistic regression, linear discrimina...

The knowledge of tree characteristics, especially the shape of standing trees, is important for living tree volume estimation, the computation of a wide range of forest stand features, and the evaluation of stand stability. Nowadays, nondestructive and accurate approaches to data collection in the forest environment are required. Therefore, the imp...

Circle-fitting methods are commonly used to estimate diameter at breast height (DBH) of trees from horizontal cross-section of point clouds. In this paper, we addressed the problem of cross-section thickness optimization regarding DBH estimation bias and accuracy. DBH of 121 European beeches (Fagus sylvatica L.) and 43 Sessile oaks (Quercus petraea...

The European spruce bark beetle Ips typographus L. causes significant economic losses in managed coniferous forests in Central and Northern Europe. New infestations either occur in previously undisturbed forest stands (i.e., spot initiation) or depend on proximity to previous years' infestations (i.e., spot spreading). Early identification of newly...

The paper demonstrates the multipurpose application of the normalized difference vegetation index (NDVI) derived from MODIS products for forest monitoring across the Central-European macro-region Slovakia and Hungary (i.e., the Western Carpathians and Pannonian basin). Relationships between forest dynamics and NDVI were analysed and used for determ...

The measurements of tree attributes required for forest monitoring and management planning, e.g., National Forest Inventories, are derived by rather time-consuming field measurements on sample plots, using calipers and measurement tapes. Therefore, forest managers and researchers are looking for alternative methods. Currently, terrestrial laser sca...

The close-range photogrammetry (CRP) is a robust tool for point clouds generation. We can see a huge usage spread of the CRP in all different sectors. In our research, we are focusing on the use of CRP for forestry. Especially , for forest inventory with focus on trunk diameter. The main advantage of CRP is lower hardware costs with a comparison to...

This study compares the accuracies of diameter at breast height (DBH) estimations by three initial (minimum bounding box, centroid, and maximum distance) and two refining (Monte Carlo and optimal circle) circle-fitting methods The circle-fitting algorithms were evaluated in multi-scan mode and a simulated single-scan mode on 157 European beech tree...

Close-range photogrammetry (CRP) represents very perspective technology for many fields. It can provide results comparable to terrestrial laser scanning, and the hardware is still much cheaper. Our research group is developing low-cost CRP device based on Raspberry Pi 3 computer. Raspberry Pi 3 is a single-board computer with relatively high comput...

The increasing development of road infrastructure considerably contributes to bear habitat fragmentation. The aim of this study was to examine the relationship between brown bear movements and secondary roads. The 1463-km2 study area in the north-central Slovakia was defined by the composite home ranges (minimum convex polygon (MCP) 100%) of 21 bea...

Mobile laser scanning (MLS) is time-efficient technology of geospatial data collection that proved its ability to provide accurate measurements in many fields. Mobile innovation of the terrestrial laser scanning has a potential to collect forest inventory data on a tree level from large plots in a short time. Valuable data, collected using mobile m...

Strong wind disturbances can affect large forested areas and often occur irregularly within a forest. Due to this, identifying damaged sites and estimating the extent of these losses are crucial for the harvesting management of salvage logging. Furthermore, the location should be surveyed as soon as possible after the disturbance to prevent the deg...

Abstract: The present paper introduces a satellite-based approach to the detection of phenology events in beech forests across Slovakia (the Western Carpathians) using the MOD/MYD09 products. Normalized vegetation index (NDVI) was used for determining the onset of the phenophases in spring and autumn. Double logistic sigmoid function was applied in...

For ten years, there is a model TANABBO (JAKUŠ et al. 2005) implemented for the conditions of Central Europe. This model has been recently finalized and reformulated into model TANABBO II, representing a system providing maps and statistical evaluation of the risk of stands infested by bark beetle. The aim is to describe in detail TANABBO II model...

The efficacy of the application of terrestrial laser scanning (TLS) technology to assess soil disturbances due to log skidding activities was tested in an evenaged forest stand (110 years old) in Slovakia. An area of 18 × 52 m along a skid trail was scanned with TLS before and after skidding operations, and after the post-harvesting reinstatement u...

Vydanie tejto publikácie podporila Agentúra Ministerstva školstva vedy a výskumu Slovenskej republiky pre štrukturálne fondy EÚ (ASFEU) z operačného programu Výskum a vývoj v rámci projektu ITMS: 26220120069 „Centrum excelentnosti pre podporu rozhodovania v lese a krajine“.

The work deals with the creation of digital maps of the intensity of GSM/EDGE signal on the territory of the Forest Enterprise at the Technical University in Zvolen, Slovakia. Simulation of electromagnetic radiation intensity was calculated using the prediction program TEMS Parcell, based on technical data of transmitters and receivers, as well as...

This paper presents a new, innovative approach for the estimation of phenological events of forest stands from satellite spectroradiometer MODIS. We focused on two parts of the vegetation period: buds bursting and leaf unfolding. Normalized vegetation index (NDVI) was used to determine the onset of the vegetation stages. Sigmoid curve was applied t...

The paper describes the procedure for constructing a habitat suitability model from the distribution maps of a modelled species. If exact locations are not available, old and present thematic maps indicating species distribution can be used instead. We developed this procedure to create the brown bear (Ursus arctos) habitat suitability model in Slo...

Biotic agents driven spruce decline has been observed over several regions in Europe. We studied the spatial pattern of spruce stands mortality due to biotic agents in three spruce dominated regions in Slovakia - the Kysuce, Orava and Low Tatras regions. Regularly reported data on sanitary felling were used for the analysis. Geostatistical tech - n...

Geostatistical analysis of bark beetle activity and its use for the improvement of pest control measures are presented. Data on the volume of salvage timber felling due to bark beetle infestation for the period 2002-2004 were used for the analysis. Research was carried out in the northwestern part of Slovakia. The techniques used were variogram mod...

Many of the large terrestrial mammals have vast home ranges. When migrating between suitable core habitats their movements encompass several square kilometres, without stops at national boundaries. For their long-term survival the populations need the genetic exchange between sub-populations. Therefore migration and movement over longer distances i...

The sources of biomass in Banská Bystrica region were identifi ed and the total volume of biomass estimated. The growing stock, planned fellings, assortments structure, forests age structure, ownership and other factors were taken into account. Smallwood (under 7 cm in diameter) volume was set to 18% for all tree species and felling types. The limi...

Integration of various computer platforms and software packages will result in a powerful system for modelling and database management. A distributed computing environment allows work groups to be flexible and to combine to solve problems. The aggregate resources of several computers facilitate the flow of information among scientists, specialists,...