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The silver fir (Abies alba Mill.) is among the most valuable conifers in Europe for ecological and economic reasons. Throughout the course of history, primarily in the 20th century, its share in stands has been declining due to ill-suited management practices, especially clear-cut management, air pollution (SO2 and NOX emissions), and wildlife-induced damage. This literature review compiles findings from 338 scientific papers. It describes futures for silver fir and its distribution, ecological requirements, threats and diseases, seed production and nurseries, and forest management practices with emphasis on ongoing climate change. Based on recent knowledge of fir ecology and population dynamics, small-scale shelterwood and selection management have been introduced in fir stands, which have also stabilized them. Fir is an essential species for maintaining high stability and biodiversity, especially on planosols and in waterlogged habitats. Owing to its shade tolerance and environmental plasticity, it can coexist very well with many tree species in mixtures, which can increase the productive potential of stands within the natural range in Europe. The average stand volume of mature fir stands ranges from 237–657 m3 ha−1. For its successful natural regeneration, it is essential to reduce cloven-hoofed game and thus prevent bud browsing damage. The attractiveness of fir in terms of heavy browsing is the highest of all conifers (52% damage). On the other hand, fir is a species relatively resistant to bark stripping and the spread of secondary rot compared with Norway spruce (Picea abies [L.] Karst.). Under global climate change, fir is expected to shift to higher elevations with sufficient precipitation, while in the southern part of its natural range or at lower elevations, outside water-influenced habitats, it is likely to decline. Climate change is intricately linked to the heightened prevalence of forest pathogens with significant damage potential in Europe, necessitating careful consideration and strategic adaptation within management practices of fir forests. [ABSTRACT FROM AUTHOR]

Norway spruce stands are established and managed along various site conditions in central Europe. Currently, spruce often grows at locations outside of its ecological optimum, resulting in extensive damage elicited by harmful abiotic and biotic factors, which relatively shortens the time to change this adverse status in the adaptation frame by foresters. Except for the rapid change in species composition through clear-cuts, another way is possible, i.e., stabilising current (especially young) spruce stands to extend the time required to implement adaptation measures. The assumption that different site conditions will have to be respected as part of this adaptation was confirmed by our study based on NFI data of the Czech Republic. A semiparametric generalized linear model (GAM) was used to model the relationship between the height-to-diameter ratio and forest stand age, differentially considering particular forest vegetation zones. Spruce stands with lower elevations attain a lower stability (expressed by their height-to-diameter ratio; HDR) than those in the mountains. The HDR culminated in lower and middle altitudes in the first half of the rotation period, representing the most critical timing and effectivity of silvicultural measures. Contrary to previous findings, we found higher HDR values at nutrient-rich sites than those at acid ones, especially up to 50–60 years old. Therefore, more research should be devoted to the issue concerning the same thinning regime under different site conditions. [ABSTRACT FROM AUTHOR]

Scots pine has been considered a resistant tree species not only to adverse habitats but also to drought for a long time for its pioneering character, enabling it to thrive at significantly nutrient-poor and dry sites where the competitive pressure of other tree species is reduced. It has also some physiological properties adapted for the increased efficiency of water management. However, the increased and cumulated drought stress in Central Europe after 2013, which has accelerated significantly since 2015, showed the limits of the Scots pine´s sustainable prosperity in many sites of its present occurrence. The research analyses 101 studies published in the period from 1975 to 2022, representing basic properties, ecophysiological aspects, health status development, growth and fertility of Scots pine related to drought stress. It also deals with the influence of the tree species mixing effect and silvicultural management on the health status of Scots pine stands. The review aims to provide comprehensive material for understanding the development of Scots pine´s health and growth, as well as optimising its use under ongoing global climate change conditions characterised by an increase in annual air temperatures and by irregular distribution of precipitation, leading to the increasing frequency of drought periods. Methodological recommendations for silviculture in pine forests are also mentioned here. [ABSTRACT FROM AUTHOR]

(1) Background: The growth and morphology of Norway spruce (Picea abies (L.) Karst.) juveniles were observed under different light conditions due to overstory canopy openness. The aim was to investigate the photo-morphological responses of juveniles for the development of a desirable forest structure. The research was located in a higher altitude zone in central Europe. (2) Methods: Light was estimated using hemispherical photographs. Eight different parameters of natural regeneration were measured on individuals within 1 × 1 m around each point on a 3 × 3 m grid. A total of 1214 sapling measurements (from 10 to 431 cm in height) were taken. (3) Results: Light affected the growth and morphological development of juveniles, resulting in variation in the lateral crown growth and crown length. Acclimations manifested as trade-offs between height and lateral crown growth. Similar shifts were found within relative height growth (the terminal length to the total height) and apical dominance ratio (the terminal length to the branch length). The crown length was proven to be highly capable to acclimation. Light influenced the density weakly, however, when a regeneration index (density × median height) was considered, significant relations with light conditions were discovered. [ABSTRACT FROM AUTHOR]

A random intercept for each triplet and year for Quercus robur and Quercus petraea (top) and Pinus sylvestris (bottom) showing the inter-annual variation in diameter increment on different sites at the logarithmic scale in mm. [Display omitted] • Tree growth reactions to climate are highly site-specific within a bioclimatic zone. • Local (micro)-site conditions outweigh large-scale climatic patterns. • Tree growth reactions to climate are dependent on relative tree size. • Growth sharply declines with increasing potential evapotranspiration in June. • Species identity and mixture effects clearly differ between years at the same site. Quercus robur / Quercus petraea and Pinus sylvestris are widely distributed and economically important tree species in Europe co-occurring on mesotrophic, xeric and mesic sites. Increasing dry conditions may reduce their growth, but growth reductions may be modified by mixture, competition and site conditions. The annual diameter growth in monospecific and mixed stands along an ecological gradient with mean annual temperatures ranging from 5.5 °C to 11.5 °C was investigated in this study. On 36 triplets (108 plots), trees were cored and the year-ring series were cross-dated, resulting in year-ring series of 785 and 804 trees for Q. spp. and P. sylvestris , respectively. A generalized additive model with a logarithmic link was fit to the data with random effects for the intercept at the triplet, year and tree level and a random slope for the covariate age for each tree; the Tweedie-distribution was used. The final model explained 87 % of the total variation in diameter increment for both tree species. Significant covariates were age, climate variables (long-term mean, monthly), local competition variables, relative dbh, mixture, stand structure and interactions thereof. Tree growth declined with age and local density and increased with social position. It was positively influenced by mixture and structural diversity (Gini coefficient); mixture effects were significant for P. sylvestris only. The influence of potential evapotranspiration (PET) in spring and autumn on tree growth was positive and non-linear, whereas tree growth sharply decreased with increasing PET in June, which proved to be the most influential month on tree growth along the whole ecological gradient. Interactions of PET with tree social position (relative dbh) were significant in July and September for Q. spp. and in April for P. sylvestris. Interactions of climate with density or mixture were not significant. Climatic effects found agree well with previous results from intra-annual growth studies and indicate that the model captures the causal factors for tree growth well. Furthermore, the interaction between climate and relative dbh might indicate a longer growth duration for trees of higher social classes. Analysis of random effects across time and space showed highly dynamic patterns, with competitive advantages changing annually between species and spatial patterns showing no large-scale trends but pointing to the prevalence of local site factors. In mixed-species stands, the tree species have the same competitivity in the long-term, which is modified by climate each year. Climate warming will shift the competitive advantages, but the direction will be highly site-specific. [ABSTRACT FROM AUTHOR]

One of the main ideas of non-native tree species introduction into forest stands is to replace declining native species. The same is also valid for industry; the wood of native species should be replaced by a wood of the same or even better quality. Douglas-fir is often compared to other coniferous tree species based on its production. This study compared Douglas-fir wood properties with European commercial species, namely Norway spruce, Scots pine, and European larch. Trees representing different sites and ages were tested for wood density, shrinkage, and compression strength. In all cases, Douglas-fir outclassed spruce and pine in density and strength. The difference was striking, especially for spruce, where the density was surpassed by Douglas-fir by more than 100 kg.m−3 (above 25%). In the case of compression, the strength of Douglas-fir was up to 12.3 MPa higher (above 33%) compared to spruce. The only species that obtained higher figures was larch. Wood shrinkage was comparable to European softwoods. Therefore, Douglas-fir wood can be regarded as an excellent and promising substitute for the European processing industry. • Douglas-fir represents promising non-native species for Europe. • It should be a substitute, especially for Norway spruce in industry. • We tested some of the properties important for applications. • In contrast to previous studies, tested species grew together in the same stand. • Douglas-fir exceeded not only spruce but also Scots pine. [ABSTRACT FROM AUTHOR]