Compared with far-developed measures and methods for mono-specific forest stands, the silvicultural prescriptions for mixed-species stands are at their early beginning. However, they are essential ...for the well-conceived establishment, design, and control of mixed-species stands, currently promoted in many countries worldwide. Here, we review the state of the art and we further develop silvicultural prescriptions for mixed-species stands for steering of experiments, stand modeling, and silviculture. We review which aspects of tree species mixing are most relevant for management goal achievement. We found the maintenance of species diversity and structural heterogeneity for ecological purpose, stabilizing productivity, and social-economic performance as main objectives. We give an overview of quantitatively formulated silvicultural prescriptions for steering mixed-species stands for forest practice, long-term experiments, forest stand models. Compared with the sophisticated guidelines for mono-specific stands, prescriptions for mixed stand are often mainly qualitative and vague. Then, we introduce methodological approaches in development for steering mixture: measures for spatial and temporal separation, species-specific growing space requirements for crop trees, coefficients for equivalence and density modification, and basic relationships for steering tree number and area-based mixing proportions. Finally, we draw conclusions for further development of methodological approaches for silvicultural steering of experiments, implementation in stand simulators, and for silvicultural operations. We see the need for improving the quantitative spatially explicit rules based at tree or cohort level, for substantiating the knowledge on species-specific allometry, growing area, tree-to-tree distances, and position-dependent competition indices for steering tree removal. We discuss the prospects and limitations of establishing silvicultural prescriptions for mixed-species stands that inevitably will be more complicated than those for mono-specific stands, and we draw conclusions for next steps in science and practice.
The main objective of this study was to assess the influence of surrounding forest and agricultural landscapes on the bird communities within cities. Using the point count method, we collected data ...and analyzed the species richness and relative abundance of breeding birds. We found differences in the species richness and relative abundance of breeding birds between urbanized areas surrounded by forests and agricultural landscapes. However, both types of landscapes significantly differed in terms of bird community structure. The highest relative abundances of bird species were observed in city forest parks and cities surrounded by forest landscapes, while the lowest abundances were detected in highly urbanized areas. Cities surrounded by forests exhibited an additional nine species compared to other areas. The ecological grouping of species revealed that cities surrounded by forests had higher relative abundances of typical forest species, such as the Great Tit (Parus major), Eurasian Blue Tit (Cyanistes caeruleus), Common Chaffinch (Fringilla coelebs), and European Pied Flycatcher (Ficedula hypoleuca), whereas cities surrounded by agricultural landscapes were characterized by bird communities adapted to open or semi-open landscapes with specific feeding and nesting behaviors. The presence of specialist forest species in the composition of urban bird communities enhances biological diversity, which is crucial for the stability of both urban ecosystems and bird communities.
Fire is an important natural disturbance and a driver of hemi-boreal forest successional trajectories, structural complexity, and biodiversity. Understanding the historic fire regime is an important ...step towards sustainable forest management. Focusing on Lithuania’s hemi-boreal forests, we first mapped the potential natural fire regimes based on the relationship between site conditions, vegetation, and fire frequency using the ASIO model. The ASIO model revealed that all the fire frequency categories (Absent, Seldom, Intermittent, Often) are found in Lithuania. Scots pine forests dominated the often fire frequency category (92%). Secondly, focusing on a fire-prone forest landscape, Dzūkija, we analyzed the fire occurrence of Scots pine forest types using dendrochronological records. We sampled and cross-dated 132 Scots pine samples with fire scars from four dry forest stands (n = 92) and four peatland forest stands (n = 40), respectively. In total, the fire history analysis revealed 455 fire scars and 213 fire events during the period of 1742–2019. The Weibull median fire intervals were 2.7 years (range 1–34) for the dry forest types and 6.3 years (range 1–27) for the peatland forest types. Analysis pre- and post-1950 showed the Weibull median fire interval increased from 2.2 to 7.2 for the dry forest types but decreased from 6.2 to 5.2. for the peatland forest types. A superposed epoch analysis revealed significant precipitation fluxes prior to the fire events after 1950. Thus, the Dzūkija landscape of Lithuania has been strongly shaped by both human and naturally induced fires. The combination of theory (the ASIO model) with the examination of biological archives can be used to help guide sustainable forest management to emulate forest disturbances related to fire. As traditional forest management focusing on wood production has eliminated fire, and effectively simplified forest ecosystems, we recommend introducing educational programs to communicate the benefits and history of forest fires as well as adaptive management trials that use low-intensity prescribed burning of Scots pine stands.
The Forest Stewardship Council (FSC) forest certification system is a globally widespread market-driven mechanism that aims at responsible use and governance of forests, and its application is ...growing. However, the extent to which forest certification contributes effectively to maintaining forest biodiversity is an unresolved issue. We assessed the role of FSC certification for forest biodiversity conservation in Lithuaniaâs state forests. First, we analysed the indicators related to biodiversity conservation at different spatial scales in the FSC standard used in Lithuania. By applying morphological spatial pattern analysis and habitat suitability modelling, we explored the structural and functional connectivity of forest habitat patches of formally and voluntarily set-asides for biodiversity conservation. According to the Lithuanian FSC standard, active measures in forest management for biodiversity should be imposed at three spatial scales: âtrees in a standâ, âstands in a landscapeâ, and âlandscape in an ecoregionâ. The total area set aside for biodiversity was 18.6Â %, including 4.9Â % voluntary set-asides. The quality of habitats in terms of forest stand age was low, only 9.4Â % of all set-asides constituted older forests. The proportions of voluntary set-aside area varied among the different state forest enterprises, and the results indicated a clear trend to set aside non-forest or low productivity forest habitats. Small (<1Â ha) habitat patches formed a major part of all set-asides, including formally protected areas. FSC certification alone was not able to maintain structural and functional connectivity of forests for species at multiple spatial scales in Lithuania. By keeping a minimum standard of 5Â % forestland set aside for biodiversity, the state forest enterprises certified according to the FSC can only satisfy forest species with small habitat requirements. To maintain biodiversity, place-based learning among stakeholders for representative functional green infrastructures in concrete landscapes and regions, combined with transparent knowledge about the net effect of pressures and responses on the state of biodiversity, are necessary.
In Lithuania, free-ranging European bison live sedentarily in the fragmented landscape of the central part of the country. The aim of this study was to analyze the distribution and habitat selection ...of European bison in a semi-isolated territory. Free-ranging European bison living sedentarily have formed six groups in the mosaic landscape of central Lithuania. A herd of 34 individuals of European bison entered into a new semi-isolated territory in 2016. During the snow-free season, we tracked the movements of the herd by fitting a global positioning system (GPS) collar to the leading cow. To evaluate the home range and habitat selection, we used ArcGIS software, Jacobs’ index, and chi-square testing to verify significant differences between proportions. The home range of European bison was largest in spring, decreased in summer, and increased again in autumn; this was associated with feeding and the food supply in agricultural lands. European bison spent more time in the forest, especially during the daytime, due to disturbance, but in summer time and at night, the bison did not avoid agricultural land. In the forests, European bison preferred clear-cut, small-leaved deciduous (aspen, grey alder) forests of middle and mature age, but they avoided broad-leaved deciduous (ash), coniferous, and young forests. The increased number of European bison caused damage to agricultural crops and increased conflict with farmers.
We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to ...identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija.
In Lithuania, key and potential key forest habitats (hereinafter (P)WKH) were inventoried for the first time during 2000–2004. A repeated inventory of existing and newly established habitats was ...carried out during 2013–2017. This study assessed changes in (P)WKH over a period of 10–15 years between the main and repeated inventory. The gathered long-term and numerous information on the key biological elements of (P)WKH, rare species (mosses, lichens, vascular plants, mushrooms, beetles and molluscs), negative factors and the most appropriate measures for the preservation of biological values were analysed. The results showed that over a period of 10–15 years, 90.5% of woodland key habitats (WKH) remained stable or improved, and the status of potential woodland key habitats (PWKH) remained stable or improved in 60.3% of all PWKHs. The most significant changes were identified in the scenarios of WKH change into potential and PWKH change into key habitats. According to the PKMB to WKH change scenario, all investigated biological elements had a significant increased tendency of 1.2–2.3 times. All investigated biological elements decreased 1.4–3.9 times according to the WKH to PKMB change scenario. During the 10–15 years period, most WKH and some PWKH confirmed their potential to conserve and enrich biodiversity in a relatively small area, thus ensuring the function of a sustainable forest landscape as rare species habitats and being part of a network of protected areas. Special attention should be given to the necessary measures for the conservation of (P)WKH biodiversity (protection against economic use and application of nature management measures), continuous monitoring of these areas, as well as the admission and implementation of the legal framework for forest habitats in the general forest management policy.
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