Krunoslav Teslak

Ash dieback, together with altered hydrological conditions and limited natural regeneration, threatens narrow-leaved ash (Fraxinus angustifolia Vahl) forests in Croatian floodplains. This study evaluated whether individual-tree attributes and stand structure were associated with crown damage and short-term radial-growth resilience. Ten stands in the middle Sava River floodplain were sampled using 41 circular plots. Stand density, basal area, and growing stock were estimated at the plot level. Diameter, height, crown dimensions, and crown damage were assessed on a subsample of 154 trees, from which increment cores were also collected. Ring-width measurements were used to calculate the Resilience index (Rs_3/6). Relationships among variables were evaluated using linear correlation and one-way analysis of variance was used for testing differences in crown damage and resilience index between categorized tree and stand variables. Mean crown damage was 24.4%, while the mean Rs_3/6 value of 0.90 indicated that radial growth had generally not returned to its previous level. Crown damage was negatively correlated with growth resilience. Trees in the 15–30 cm diameter class and the 21–40-year age class showed the lowest crown damage and highest resilience. The most favorable values of both indicators occurred at stand densities of 800–1200 trees ha⁻¹, while crown damage was lowest at basal areas below 15 m² ha⁻¹. Although the observed associations were moderate and should not be interpreted as causal effects, the combined use of crown condition and radial-growth recovery can support the identification of vigorous trees and inform adaptive, site-specific management of declining narrow-leaved ash stands.

Forests in Croatia are characterized by higher levels of biodiversity in species composition. Three significant events occurred in Croatian forests over the past ten years, all of which have a common denominator—sanitary felling. The challenge in the sustainable development of forests started with the ice storm of 2014 that amounted to damage and raised costs in forest stands to EUR 231,180,921. The second challenge was in 2017 when the bark beetle outbreak occurred in the Gorski Kotar region. In December 2017, a windstorm in the same area caused damage to approximately 500,000 m³ of wood stock. The third climate extreme was in the summer of 2023 when three storms with strong winds and heavy rain damaged even-aged forests of common beech and pedunculated oak. The damage was substantial: 3,954,181 m³ of timber was mostly broken and destroyed across 21,888.61 ha of area, and the most damage was in the pedunculate oak forests of Slavonia, i.e., Quercus robur subsp. Slavonica, at 1,939,175 m³. For the main meteorological stations in lowland Croatia, data on precipitation amounts (mm) and wind speeds (m/s) were collected for the period 1981–2023, and the results of our analysis for the last decade are presented. Meteorological drought was analyzed using the rain anomaly index RAI. Data regarding open space fires in the Mediterranean karst area of Croatia were collected from the Croatian Firefighting Association, and the calculation of the burned area index (BAI) was determined. Throughout the entire area of Gorski Kotar County, a sample of permanent plots was set and used to assess the extent of forest damage from the ice storm in 2014 and for the establishment of permanent monitoring of the recovery of trees and forests damaged by the ice storm. The monitoring of bark beetles in the Gorski Kotar region started in 1995 and is still in progress. The aftermath of bark beetle outbreaks in two uneven-aged silver fir stands was studied after a bark beetle outbreak and a sanitary felling of 4655.34 m³. In the area of lowland Croatia, a statistically significant and positive correlation was found between sanitary fellings, maximum wind speeds, and rain anomaly indices in even-aged forests. In conclusion, sustainable development will be at risk due to difficult recovery, rising costs, and overall climate change in the years to come.

Temelji moderne šumarske znanosti i struke u Hrvatskoj (preporodno razdoblje) postavljeni su tijekom 19. stoljeća. U relativno kratkom vremenu tijekom druge polovine 19. stoljeća osnovano je Hrvatsko-slavonsko šumarsko društvo (1846), pokrenut je Šum...

The environmental, social and economic potential of Dinaric uneven-aged forests along with the complex stand dynamics influenced by different long-term management approaches and environmental factors require comprehensive forest monitoring. This study aimed to explore differences in the current status and recent past dynamics of stand structures between unmanaged and managed mixed fir-beech forests in the Croatian part of the Dinaric Alps using large-scale data from an established monitoring system. From the 74 permanent sample plots distributed within the forest type measured in 2008 and re-measured in 2019, we stratified four strata (types of management regimes): (1) forests out of regular management and tree harvest for at least 30 years, (2) managed state forests on carbonate bedrock, (3) managed state forests on non-carbonate bedrock and (4) managed private forests. In each sample plot, 34 structural attributes were computed to assess indicators of their current status and recent past dynamics of stands in the studied forests. An increasing Q shape diameter distribution with a high number of large and very large trees characterize unmanaged forests and managed forests on non-carbonate bedrock. In managed state forests and private forests, variable (rotated sigmoid) and constant (negative exponential) results were obtained, respectively. Principal component analysis (PCA) distinguished managed and unmanaged forests with decreasing harvest volume and recruitment, increasing basal area, number of very large trees, average diameter at breast height (DBH), crown defoliation of firs and basal area of died beech trees. The current structure, recent and expected stand dynamics in the unmanaged forests (accumulation of standing volume, increase of large diameter trees and large snags, large share of beech, large mean DBH) can be recognized as old-growth attributes. The differences between the studied forest types, potential of both unmanaged and state managed fir-beech forests and approaches to sustain multifunctional forest management in the Dinaric region were discussed.