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Keywords: socioeconomic development, forest resources, forest ecosystems, forest degradation, forest landscape restoration, forest fire management, urban forests, peri-urban areas, sustainable forest management, Mediterranean region
Published in DiRROS: 09.01.2026; Views: 417; Downloads: 183
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Abstract: Bark beetle outbreaks have caused large-scale tree mortality and damage in recent decades, primarily following an increase in largescale forest disturbances induced by climate change. After tree logging operations, leftover branches are traditionally piled to make the potential brood material less suitable for bark beetles, thereby lowering the risk of subsequent attacks on surrounding trees. On the other hand, the residues could prove valuable to biodiversity by supplementing important habitat, given the apparent decline in deadwood in European forests and its associated saproxylic fauna. Our aim was to identify the most successful method of logging residue management for both bark beetle management and biodiversity. We focussed on Norway spruce felling residues, their associated bark beetle pests and saproxylic insect orders, beetle families, and Cerambycidae species.We prepared four treatments: (i) logging residues in piles, (ii) scattered logging residues, (iii) logging residues removed, and (iv) a control plot with no felling activity. Five plots per treatment were established at each site. In total, three sites were selected: one at a high elevation and two at lower elevations in different parts of Slovenia. The catch was counted to the order level, the attracted beetles were identified to the family level, and Cerambycidae and Scolytinae to the species level. We found that the treatments with residues attracted the highest diversity of insect orders and the most beetles across different families, including Cerambycidae. Furthermore, we found that the species composition differed between control and residue treatments, although no difference was observed in species richness. More bark beetles and a higher number of bark beetle species were attracted to both piled and scattered residues. Thick branches were more frequently attacked in scattered residues. There was no difference in the number of attacked trees (within a plot) one month after treatment. Hence, leaving logging residues in the forest could represent an interesting compromise between pest management and biodiversity conservation. Conf licting aims, such as increasing biodiversity or controlling bark beetles, should be carefully considered in the management decisions.
Keywords: Scolytinae, forest management, Cerambycidae, Norway spruce, multipurpose forest management, felling residue
Published in DiRROS: 21.07.2025; Views: 530; Downloads: 314
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Abstract: Understanding competition between trees is essential for sustainable forest management as interactions between trees in uneven-aged mixed forests play a key role in growth dynamics. This study investigated nine competition indices (CIs) for their suitability to model the effects of neighboring trees on silver fir (Abies alba) growth in Dinaric silver fir-European beech (Fagus sylvatica) forests. Although numerous competition indices have been developed, there is still limited consensus on their applicability in different forest types, especially in mature, structurally complex forest stands. The indices were evaluated using the adjusted coefficient of determination in a linear model wherein the volume growth of the last five years for 60 dominant silver fir trees was modeled as a function of tree volume and competition index. The results demonstrated that distance-dependent indices (e.g., the Hegyi height-distance competition and Rouvinen-Kuuluvainen diameter-distance competition indices), which consider the distance to competitors and their size, perform better than distance-independent indices. Using the optimization procedure in calculating the competition indices, only neighboring trees at a distance of up to 26-fold the diameter at breast height (DBH) of the selected tree (optimal search radius) and with a DBH of at least 20% of that of the target tree (optimal DBH) were considered competitors. Therefore, competition significantly influences the growth of dominant silver firs even in older age classes. The model based solely on tree volume explained 32.5% of the variability in volume growth, while the model that accounted for competition explained 64%. Optimizing the optimal search radius had a greater impact on model performance than optimizing the DBH threshold. This emphasizes the importance of balancing stand density and competition in silvicultural practice.
Keywords: sustainable forest management, Dinaric silver fir-European beech forests, Competition indices, CIs, optimal search distance, optimal diameter at breast height, DBH
Published in DiRROS: 05.06.2025; Views: 600; Downloads: 362
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Keywords: Close-to-nature, forest sustainable management, climate changes, oaks, Quercus
Published in DiRROS: 01.02.2025; Views: 755; Downloads: 406
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Keywords: Close-to-nature, forest sustainable management, climate changes, beech, Fagus sylvatica L.
Published in DiRROS: 01.02.2025; Views: 748; Downloads: 445
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