European Journal of Forest Research最新文献

Abstract

Cavities made by birds are an important microhabitat for many taxa in forests. Long-term dynamics of cavity patterns and the effect of forest management on cavities are, however, largely unknown. We studied cavity production, measured as nest cavity production rates (CPR = no. of new cavities/km²/year), of woodpeckers and tits in forests with different management intensity in southern Finland, based on a data from 37 years. Forests were divided into managed, seminatural and natural stands. The data covered 56 forest stands with the total area of 1690 ha. Stands were inventoried annually for new cavities. The total numbers of woodpecker and tit cavities were 2238 and 329, respectively. There were large differences in CPRs between forest stands with different management intensity. For woodpeckers, the CPR was highest in natural forests (5.7) and lowest in managed forests (1.5). For the tit species, the respective numbers were 0.9 and 0.3. The CPRs of different cavity-making bird species and cavity tree characteristics (e.g. tree condition and species) were consistent, suggesting that different cavity-makers benefit from similar forest and tree characteristics. The results also suggest that forests managed with currently prevailing methods limit the production of cavities. To promote cavities, the results from this and other studies suggest that managed forests should include more features of natural forests, such as more diverse tree species and within-stand structural variability distribution (tree-level heterogeneity), larger amount of decayed wood, more retention trees and snags and longer rotation periods.

Afforestations provide cost-effective and environmentally friendly protection against natural hazards, compared to technical measures. In Austria, more than 3000 afforestation sites for hazard protection covering 9000 ha have been established between 1906 and 2017, mainly for snow avalanche protection. The actual protective effect depends on avalanche predisposing factors and land cover, i.e. whether forest is present. In this study, predisposing factors and land cover classes were identified and analysed in selected afforestation sites. The protective effect of forest was attributed to the presence of forest cover and tree species. Using RGB images with a ground resolution of 20 × 20 cm, nine land cover categories have been distinguished by means of supervised classification with the random forest algorithm. Those land cover categories were classified with an overall accuracy of 0.87–0.98 and Kappa-values, ranging between 0.81 and 0.93. Images were filtered using a 3 pixel by 3 pixel majority filter, which assigns each cell in the output grid the most commonly occurring value in a moving window centred on each grid cell. This filter further increased the overall accuracy by removing noise pixels while preserving the fine elements of the classified grid. Our results indicate a protective effect for about half of the analysed afforestation sites. The dominance of the land use class “Meadow” at most sites with little avalanche protection effect suggests grazing as a limiting factor. The spatial information provided with the described method allows to identify critical areas in terms of avalanche protection even years after the initial afforestation.

Forest reclamations have been very commonly used on post-mining sites in central Europe and offer great opportunities for research of soil formation process. Antonín forest arboretum near Sokolov, Czech Republic, reclaimed and afforested between 1972 and 1974 was the opportunity to compare the influence of only the vegetation variable. In this research, physical and chemical soil properties from the uppermost mineral 5 cm of 23 stands (11 broadleaved and 12 coniferous) were analysed and compared. Soil pH, bulk density, porosity, water retention capacity, organic and total carbon and nitrogen content, plant available nutrients and potentially toxic elements were analysed. From the species tested, the soil properties that can generally be considered beneficial were noticed in Alnus glutinosa, Fagus sylvatica, Tilia cordata, Pyrus communis, Picea pungens and Pinus ponderosa. On the other hand, species that have not shown these soil properties were Betula pendula, Larix decidua, Picea abies, Pinus rotundata, Pinus strobus and Pinus sylvestris. It is also worth mentioning that, although some species have shown soil properties that can be considered more or less favourable from a pedological point of view, the choice of species for afforestation of post-mining sites needs to consider other factors as well, like stand health, growth potential, affinity to climatic, hydrological, and other factors, potential invasiveness, susceptibility to pathogens.

Graphical abstract

Forest phenology is undergoing significant changes as a consequence of climate warming, something which is further complicated by snow cover phenology. While previous research has shown tight links between climate factors, snow cover and forest phenology changes, the relative importance of climate and snow cover on forest phenology has not yet been fully quantified. Here, we analyzed the variations of forest phenology and the influences of different factors on the changes of forest phenology in Changbai Mountains from 2001 to 2019. We extracted forest phenology [start of growing season (SOS), length of growing season (LOS) and annual maximum NDVI (NDVI_max, indicating peak growth)] using MODIS NDVI and analyzed their spatio-temporal patterns. We found advanced SOS (− 0.4 days/year), prolonged LOS (0.84 days/year) and enhanced peak growth (0.002 year⁻¹) of forest at the regional scale. Then we analyzed the effects and relative importance of seasonal climatic factors and snow cover phenology on variations of forest phenology changes. The results indicated that spring temperature was the most important factor causing forest phenology changes. Snow cover duration and snow cover end day also played key roles on forest phenology changes. Snow cover end day showed positive influence on SOS and negative influence on LOS and peak growth. Spatially, the dominant factors affecting forest phenology varied among hydrothermal gradients. Our study provides useful insights on assessment and quantify the influences of climatic factors and snow on forest phenology, which are essential to predict the response of forests under global warming.

Docynia delavayi (Franch.) Schneid. is a wild fruit tree that can be widely used for medicinal and edible purpose and has a high value of exploitation and utilization. We analyzed the growth traits of 62 half-sib families from 10 provenances in order to acquire more information about the genetic variance of growth traits in D. delavayi. Variation analysis, correlation analysis, principal component analysis, estimation of genetic parameters and comprehensive analysis were all done based on the data on growth traits. The results of the variance analysis revealed that all traits, with the exception of branch length, differed significantly or extremely significantly between provenances, whereas only leaf length did not differ significantly between families. The results of the correlation analysis showed that all growth traits, except for branch length and petiole length, had a significant or extremely significant correlation with the geo-climatic factors. Three principal components were extracted by principal component analysis; they were used as indicators for the comprehensive evaluation of D. delavayi from different provenances, and five excellent provenances were selected: Lancang (LC), Lianghe (LH), Shidian (SD), Yingjiang (YJ) and Xiangyun (XY). The results of genetic parameter estimation showed that all indicators except leaf length and leaf width had a high potential for genetic improvement. Therefore, five traits (seedling height (SH), ground diameter (GD), branch length (BL), petiole length (PL) and the total number of leaves (TNL)) were used as comprehensive index to select superior families, and a total of 20 superior families were selected. This study will lay a theoretical foundation and practical guidance for the genetic improvement of D. delavayi.

Mountain forests provide multiple benefits but are threatened by climate change-induced forest dieback. Although many studies summarize perceptions of forest ecosystem services, relatively few deal with mountain forests. The local population’s perception of forest dieback in mountain forests in relation to climate change has rarely been investigated so far. Their perspective is relevant as local people are often deeply attached to “their” forests, they actively use forest ecosystems and—as voters and taxpayers—they need to support the state’s adaptation and funding measures. Therefore, this study investigates the climate change and forest dieback perception of local inhabitants in two mountain areas of Southern Germany (the German Alps and the Bavarian Forest) with a quantitative survey based on representative online samples (n = 709). Relying conceptually on van der Linden’s (J Environ Psychol 41:112–124, 2015. https://doi.org/10.1016/j.jenvp.2014.11.012) climate change risk perception model, the results show that experiential processing, cognitive and socio-cultural factors are related to locals’ forest dieback and climate change perception, while socio-demographics show no or few connections. Nearly two-thirds (64.7%) of the respondents perceive moderate to strong forest dieback, while more than half (55.0%) of the respondents already observe consequences of climate change. The perceptions of climate change and forest dieback are positively correlated with medium to high strength. This shows that forest dieback could be interpreted as an indicator of climate change, which is difficult to observe due to its long-term nature. We identify three groups of respondents regarding preferred forest adaptation strategies to climate change. In general, respondents support nature-based forest adaptation strategies over intense measures.

Increasing wildfire frequency in the Mediterranean Basin could affect future plant-soil–water-dynamics. The capacity of soils to retain water is a key parameter affecting plant post-fire regeneration. Yet, few research has looked at how different soil properties related to water retention is affected by increasing wildfire frequency. This study aimed at understanding the relationship between wildfire frequency, soil–water-related properties and the dynamics of surface water in soils. To this, after a 2012-summer wildfire in Portugal, three sets of three replicate maritime pine stands with contrasted wildfire frequency were selected (0 vs. 1 vs. 4 fires since 1975). At each of the nine study sites, three re-sprouter shrubs and neighbouring bare soil were chosen (54 microsites). There, soil cover, soil–water retention curves and surface (0–5 cm) soil–water-related properties (texture, bulk density, organic matter content, soil moisture, soil surface water repellency) were monitored for one year. Furthermore, records of post-fire soil moisture dynamics were analysed continuously using 72 probes installed at 2.5 and 7.5 cm depth. The hillslopes affected by 1 fire showed higher plant recovery than the 4 fires hillslopes. During the dry season, the threshold for water stress was reached 17 days sooner in the 4 fires hillslopes, and also 10 days sooner on bare microsites. Periods of plant water stress were longer and bare soil patches size bigger. The increase in wildfire frequency promoted high soil organic matter contents but less available water content, stressing the importance of soil organic matter quality characterization in water-related properties.

Mixed-species forests can provide higher levels of ecosystem functions and services and can be more resistant and resilient in the face of global change. While many studies focus on the growth and yield of mixed forests, fewer have examined the underlying processes. Inter- or intra-specific differences and interactions influence tree- and stand-level light absorption by determining the vertical structure of stratified canopies, stand density, leaf area index, and the size or allometry of trees. While canopy light absorption is a very important process, it is difficult to quantify it for individual species within a mixture and is rarely examined. A detailed tree-level model (MAESTRA) was used in combination with measurements of tree sizes and stand structures to examine effects of mixing on absorbed photosynthetically active radiation (APAR) in 41–63-year-old stands of Pseudotsuga menziesii and Fagus sylvatica at three sites in Bavaria, Germany. The effects of initial stand density on APAR were analysed in 46-year-old P. menziesii stands of a spacing experiment at two sites. At the tree level, mixing increased mean height and leaf area, growth (185% higher) and APAR (85% higher) of P. menziesii at all sites. Mean tree heights and crown sizes of F. sylvatica were larger in mixtures, while recent growth rates and APAR were not significantly different to monocultures. Planting density did not influence mean tree variables (e.g. height, leaf area, crown volume), because any initial spacing effects had been gradually removed by thinning across all treatments. At the stand level, there were no differences in growth, basal area or in the annual growth per annual APAR (light use efficiency, LUE) between monocultures and mixtures. The highest APAR values were observed in P. menziesii monocultures, while the lowest APAR values were observed in F. sylvatica monocultures. While mixing these species may not increase stand-level growth during later phases of development, mixing accelerated initial growth of individual trees and reduced the time to reach target diameters, which are both important aspects in adapting forests to global change.

The complex of beech taxa in western Eurasia (Fagus sylvatica L. s.l.) represents one of the most widespread broad-leaved trees in the temperate forests of the northern hemisphere. Two subspecies are generally recognized, F. sylvatica ssp. sylvatica in Europe and F. sylvatica ssp. orientalis in southwestern Asia, but several strongly differentiated regional populations were identified within this complex. To reveal geographical and genomic patterns of hybridization and introgression, genetic variation at 6789 single-nucleotide polymorphisms (SNP) resulting from ddRAD sequencing was studied in 288 specimens representing 207 populations distributed across the whole range. Two clusters resulting from a Bayesian analysis of population Structure well coincided with the subspecies, while increasing the number of clusters allowed to distinguish divergent lineages within subspecies. Two zones of potential hybridization between such lineages were analyzed: western Balkans at the contact of both subspecies and the Alpine area at the contact of populations coming from different glacial refugia. Geographical distribution of hybrid indices in the Balkan hybrid zone indicates asymmetric gene flow preferentially directed from F. orientalis to F. sylvatica. Eight SNPs showed a significant shift of genomic cline centers, seven of them toward excess F. orientalis ancestry, suggesting that introgression irregularly affects different regions of the beech genome. On the other hand, no genomic cline outliers were found in the Alpine hybrid zone. Implications for assisted gene flow are shortly discussed.