Institute of Dendrology

The historical fragmentation of forest ecosystems led to a significant spatial reduction in natural forest biomes. After centuries of exploitation for various purposes, the fragments remaining as national parks have been systematically monitored. This provides a wide range of field data and allows an in-depth understanding of processes responsible for short- and long-term forest dynamics. The existing monitoring systems should be considered unique and worth maintaining because they spanned before the era of remote sensing data acquisition in sufficient spatial and temporal resolution. We explored tree monitoring data from the oldest national park in Poland – Pieniny National Park (PNP) in the Western Carpathians, established in 1932. We assessed stand aboveground increment, recruitment, and mortality for 44 monitoring plots with field observations obtained in 1987, 1998, and 2009. Using a linear mixed-effects model, we assessed differences in stand biomass among sampling years and determined the drivers of biomass dynamics. For relative values of increment, recruitment, and mortality, we developed generalized linear mixed-effects models with a Beta distribution of the dependent variable. We found that stand composition was only slightly affected across 22 years. The mean aboveground biomass increased evenly and significantly (from 168 to 237 Mg/ha). Stand dynamics were mostly affected by stand structure characteristics, especially basal area (BA) and density, while other factors (geomorphometric and climatic characteristics) modified these relationships. The importance of climatic and geomorphometric factors shows local responses of stand dynamics, which can be utilized for fine-scale sites. We found twice higher relative increments in SW than in NE exposition, which can be related to higher insolation (sunlight and temperature) on SW-exposed hillslopes. The aboveground tree biomass change caused by mortality was partly controlled by several variables, among which the most important was BA. With increasing BA, mortality increased and was also slightly related to steeper slopes. Species-specific trends were dominated by species proportion. Fagus sylvatica had higher relative increment and mortality in plots with its dominance, while Abies alba absolute increment decreased. Studying the mountain forest dynamics is crucial for biodiversity, soil and groundwater protection, and tourism. Ground measurements are an accurate way to estimate biomass.

Abstract This study evaluates the effects of ground‐based logging on soil properties and microarthropod biodiversity in Mediterranean beech ( Fagus sylvatica L.) forests, with a focus on recovery over a 5‐year period. Fieldwork was conducted in three study areas in southern Italy to compare three site types: recently harvested (2021, NEW), harvested 5 years prior (2017, OLD), and unharvested control (>40 years ago, CON). Soil samples were collected from skid trails (DIST) and from adjacent, not‐trafficked areas (UND) to assess bulk density, penetration resistance, shear strength, organic matter content, and the QBS‐ar index of microarthropod biodiversity. Logging machinery significantly compacted the soil in DIST_NEW, increasing bulk density by 19% compared with UND_NEW. Penetration resistance tripled (0.26 vs. 0.09 MPa in CON), and shear strength rose from 1.96 to 7.18 t m −2 . The QBS‐ar index declined by 50% in comparison to the CON areas, indicating substantial biodiversity loss. After 5 years, partial recovery was observed in DIST_OLD, with bulk density and penetration resistance decreasing by 13% and 8%, respectively, though values remained above those in CON sites. These results highlight the lasting impacts of forest operations on soil health and microarthropod biodiversity. To reduce degradation, strategies such as permanent skid trail planning or use of protective technologies like logging mats are recommended. Continued research into deeper soil layers and various soil types is essential to guide more sustainable forest management practices.

Accurate detection of machinery-induced strip roads after forest operations is fundamental for assessing soil disturbance and supporting sustainable forest management. However, in Mediterranean pine forests where canopy openings after boom-corridor thinning are moderate, the effectiveness of different remote sensing techniques remains uncertain. Previous studies have shown that LiDAR-based methods can reliably detect logging trails in different forest stands, but their direct transfer to structurally simpler, even-aged Mediterranean stands has not been validated. This study addresses this gap by testing whether UAV-derived RGB imagery can achieve comparable accuracy to LiDAR-based methods under the canopy conditions of boom-corridor thinning. We compared four approaches for detecting strip roads in a black pine (Pinus nigra Arn.) plantation on Mount Amiata (Tuscany, Italy): one based on high-resolution UAV RGB imagery and three based on LiDAR data, namely Hillshading (Hill), Local Relief Model (LRM), and Relative Density Model (RDM). The RDM method was specifically adapted to Mediterranean conditions by redefining its return-density height interval (1–30 cm) to better capture areas of bare soil typical of recently trafficked strip roads. Accuracy was evaluated against a GNSS-derived control map using nine performance metrics and a balanced subsampling framework with bootstrapped confidence intervals and ANOVA-based statistical comparisons. Results confirmed that UAV-RGB imagery provides reliable detection of strip roads under moderate canopy openings (accuracy = 0.64, Kappa = 0.27), while the parameter-tuned RDM achieved the highest accuracy and recall (accuracy = 0.75, Kappa = 0.49). This study demonstrates that RGB-based mapping can serve as a cost-effective solution for operational monitoring, while a properly tuned RDM provides the most robust performance when computational resources are sufficient to work on large point clouds. By adapting the RDM to Mediterranean forest conditions and validating the effectiveness of low-cost UAV-RGB surveys, this study bridges a key methodological gap in post-harvest disturbance mapping, offering forest managers practical, scalable tools to monitor soil impacts and support sustainable mechanized harvesting.

Slope topography and aspect are among the key natural factors influencing forest growth conditions, particularly in mountainous regions. The southern slope of the Greater Caucasus Mountains in Azerbaijan is among the country's forested regions, where the oriental beech (Fagus orientalis) dominates the mid- and low-altitude zones. To study the influence of slope aspect on the distribution and forest growth conditions of oriental beech, field studies were conducted in the Gabala Forestry of the Gabala District. The study revealed that northern slopes form the most productive and stable 70-year-old stands, with a volume of up to 390 m³/ha, while productivity on southern slopes is significantly lower—160–220 m³/ha. Beech prefers moist and shaded conditions and is sensitive to microclimatic conditions determined by slope aspect. The obtained data have practical implications for rational forestry, afforestation planning and forest restoration programs on the southern slope of the Greater Caucasus.

ABSTRACTSoil disturbance resulting from forest harvesting activities can have significant and lasting environmental consequences, particularly in sensitive ecosystems such as Mediterranean forests. Skid trails, the routes used by machinery to extract timber, are among the most critical areas of impact, and their detection is critical for assessing post‐harvest impacts and informing future planning. Traditional ground‐based methods for detecting these trails are often labor‐intensive and inefficient. This study evaluates the potential of Unmanned Aerial Vehicle (UAV)‐based Laser Scanning (ULS) surveys for the accurate detection of skid trails across five Mediterranean forest sites subjected to different silvicultural treatments. Four analytical techniques were tested: Hillshading (Hill), Local Relief Model (LRM), Relative Density Model (RDM), and the machine learning‐based SkidRoad_Finder (SRF). Accuracy was assessed using a ground‐truth dataset obtained through Global Navigation Satellite System (GNSS) field mapping. Of the tested techniques, RDM performed best overall, achieving approximately 73% accuracy, 66% sensitivity, and a Cohen's kappa value of 0.50. LRM performed best in even‐aged beech forests, due to its ability to capture microtopographic changes. In contrast, SRF consistently underperformed, likely due to its reliance on training data not representative of the Mediterranean context. Our findings highlight that former skid trails and related soil disturbance can be effectively detected using ULS data. However, the accuracy and reliability of detection vary depending on site‐specific factors such as forest type, vegetation structure, and terrain complexity. Overall, this study underscores the utility of ULS for operational forest monitoring and supports the tailored selection of detection techniques based on local stand characteristics and available computing resources.

Dual mycorrhizal symbiosis, i.e., the association with both arbuscular and ectomycorrhizal fungal symbionts, is an ambiguous phenomenon concurrently considered as common among various genetic lineages of trees and a result of bias in data analyses. Recent studies have shown that the ability to form dual mycorrhizal associations is a distinguishing factor for the continental-scale invasion of alien tree species. However, the phylogenetic mechanisms that drive it remain unclear. In this study, all the evidence on root-associated symbionts of Juglandaceae from South and North America, Asia, and Europe was combined and re-analysed following current knowledge and modern molecular-based identification methods. The Juglandaceae family was revealed to represent a specific pattern of symbiotic interactions that are rare among deciduous trees and absent among conifers. Closely related phylogenetic lineages of trees usually share the same type of symbiosis, but Juglandaceae contains several possible ones concurrently. The hyperdiversity of root symbionts of Juglandaceae, unlike other tree families, was concurrently found in Central and North America, Asia, and Europe, indicating its phylogenetic determinants, which endured geographical isolation. However, for many Juglandaceae, including the invasive Juglans and Pterocarya species, this was never studied or was studied only with outdated methods. Further molecular research on root symbionts of Juglandaceae, providing long sequences and high taxonomic resolutions, is required to explain their ecological roles.

ABSTRACT Phenotypic plasticity and genetic adaptation are key mechanisms that enable species to respond to changing environments. Tree traits do not vary independently but rather in coordination. However, our understanding of whether functional traits are governed by the same mechanism is far from complete. Thus, we aim at assessing the drivers of trait variability of sessile oak and European beech provenances across their distribution ranges. We estimated growth-related and leaf morphological traits from 9 and 11 provenances of oak and beech, respectively, grown in four different common gardens distributed across their respective distribution areas. Overall, phenotypic plasticity played a dominant role in explaining individual trait variability. For most oak traits, variation among provenances and genetically based plasticity were correlated with the climate of origin, whereas fewer significant associations were found for beech. In oak, climate-transfer distance analyses revealed that traits such as DBH, height, specific leaf area, and long-term growth responses to summer temperature decreased when provenances were moved away from their local precipitation regime. In beech, significant climate-transfer distances were fewer and primarily related to temperature-related parameters. These results suggest that natural selection and local adaptation may play a secondary but notable role. The pattern of multi-trait phenotypes indicates that resource-use strategies among provenances covary with the temperatures of origin in both species. The limited genetic responses in beech could hinder its survival if it reaches the boundaries of trait plasticity, while oak may better adjust through adaptation. Our study contributes to a better understanding of the interplay between genetic adaptation and phenotypic plasticity in long-lived forest trees.

This study evaluated the efficiency of green manure (+GM) on PSII efficiency throughout the day in Dalbergia ecastophyllum. The experiment was carried out in a disabled clay extraction deposit, located approximately 30 km south of São Mateus city (Espírito Santo State, Brazil). Chlorophyll (Chl) index, Chl a fluorescence, and plant growth were measured in the summer, after 12 months of planting. +GM improved the photochemical performance of D. ecastophyllum, reducing the occurrence of photoinhibition throughout the day. +GM increased the photochemical quantum yield, the probability of a photon absorbed to move beyond quinone QA–, and the total Chl index, resulting in higher plant height and stem diameter (+11.7 and +2.2%, respectively). The number of active reaction centers per cross-section and the performance index of PSII values were unchanged throughout the day. Full recovery of both K and L-bands occurred at night. In contrast, plants growing with –GM had higher energy losses as heat. In conclusion, these results contribute to improving revegetation techniques, to create better conditions for the planting of native tree species in degraded areas.

Abstract Habitat quality and quantity play a vital role in maintaining ecosystems and populations of target species, and a deep understanding of features and metrics within the landscape is required to determine them. This chapter reviews the complexities involved in the assessment of these features and metrics to support evidence-based conservation strategies and long-term ecosystem sustainability. Evaluating habitat quality is related to structural diversity, management, natural disturbance legacy, and species richness and diversity as well as the presence of indicator or umbrella species. Generally, complex stand structures and the abundance of veteran trees and deadwood indicate ecosystems with higher levels of overall biodiversity and stability. The non-linear relationship between population viability and habitat size emphasizes the need for landscape-level management. Viability decreases significantly when the ecological capacity for a minimum viable population is exceeded, and recognizing this tipping point is therefore crucial for evidence-based conservation. This means that habitat size assessed as a single variable is insufficient to determine habitat quality, and a wider range of metrics like structural diversity and connectivity should be considered in population management at the landscape level.