The Strong Position of Silver Fir (Abies alba Mill.) in Fertile Variants of Beech and Oak-Hornbeam Forests in the Light of Studies Conducted in the Sudetes

Silver fir is one of the longest living and tallest trees in Europe, it has major commercial importance and may be found in various communities predominantly connected with lower mountainous locations in Central Europe. One of the northernmost ranges in the region is the Sudetes. Currently, the once numerous fir is greatly dispersed, with just several specimens to be found together at one site on average. This drastic reduction in the number of specimens is mainly attributable to intensive forest management, based on the artificial cultivation of fir, conducted in the 19th and 20th centuries, and high industrial air pollution (mainly in the 20th c.). Because practically no firs have been cultivated for the last 200 years, the remaining sites of the species that are remnants of its bigger populations should be regarded as natural. This paper compares fir locations with areas of potential natural vegetation. The obtained results indicate that firs may grow in various types of habitats, with the preferred one being fertile beech woods and richer variants of oak-hornbeam forests. In our opinion, the presented findings are of great importance for the knowledge of the ecology of the species in question and for providing appropriate forest management.

European primary forest database v2.0

Primary forests, defined here as forests where the signs of human impacts, if any, are strongly blurred due to decades without forest management, are scarce in Europe and continue to disappear. Despite these losses, we know little about where these forests occur. Here, we present a comprehensive geodatabase and map of Europe’s known primary forests. Our geodatabase harmonizes 48 different, mostly field-based datasets of primary forests, and contains 18,411 individual patches (41.1 Mha) spread across 33 countries. When available, we provide information on each patch (name, location, naturalness, extent and dominant tree species) and the surrounding landscape (biogeographical regions, protection status, potential natural vegetation, current forest extent). Using Landsat satellite-image time series (1985–2018) we checked each patch for possible disturbance events since primary forests were identified, resulting in 94% of patches free of significant disturbances in the last 30 years. Although knowledge gaps remain, ours is the most comprehensive dataset on primary forests in Europe, and will be useful for ecological studies, and conservation planning to safeguard these unique forests.

Terrestrial biomes: a conceptual review

Aims: We attempt to review the conceptualisation, science and classification of biomes and propose to limit the definition of a biome to potential natural vegetation as determined by general environmental variables. Results: Classifying the distribution and abundance of vegetation types on earth has been a central tenet of vegetation science since Humboldt’s classic studies in the early 1800s. While the importance of such classifications only grows in the wake of extreme changes, this review demonstrates that there are many fundamentally different approaches to define biomes, hitherto with limited efforts for unifying concepts among disciplines. Consequently, there is little congruence between the resulting maps, and widely used biome maps fail to delimit areas with consistent climate profiles. Conclusions: Gaps of knowledge are directly related to research avenues, and suggestions for defining and classifying biomes, as well as modelling their distributions, are provided. These suggestions highlight the primary importance of the climate, argue against using anthropogenic drivers to define biomes and stabilize the concept of biome to escape from the current polysemy. The last two decades have seen an emergence of new approaches, e.g., using satellite imagery to determine growth patterns of vegetation, leading to defining biomes based on the objective, observable qualities of the vegetation based on current reality.

Evaluating the post-fire natural regeneration of Mediterranean-type scrublands in Central Spain

We performed a five-year assessment of the natural vegetation restoration capacity following the 2012 fires in Valdemaqueda (Madrid, Spain) via the characterization of the post-fire and residual vegetation and the analysis of soil physico-chemical characteristics. Six pilot-plots were established in the affected site. Forest species, representative of the potential natural vegetation of the area (Juniperus oxycedrus subsp. lagunae and Quercus rotundifolia woodlands) and broom shrubs (Cytisus scoparius, Retama sphaerocarpa) were planted to assess the relationship among the stages of ecological succession, competition, and soil restoration processes following devastating fire events. The fire-driven alteration of the soil’s physico-chemical properties was evident, given the increased pH and reduced C/N ratio in the first years of the study. However, we observed an increased soil enrichment in the last years of study, accompanied by the propagation of herbaceous species, su[1]pporting our seed bank findings, showing a clear difference in the sprouting rate between burnt and control plots (80% vs. 20%, respectively). The establishment of robust, pyrophyte shrub species (Cistus ladanifer, C. laurifolius, Rosmarinus officinalis) rather than natural succession evidenced the clear conversion of the vegetation in burnt areas. These findings in the pilot-plots allowed evidencing the high vulnerability of the natural vegetation to the settling of pyrophytes, given their low survival rate under the strong competitive pressure of these pyrophytic species. The proliferation of these pyrophytes could translate into changes in soil macro- and microbiota, nutrient dynamics, species diversity, and interaction, added to the alteration of fire regimes in the area. Overall, these results highlight the risk for soil impoverishment and possible erosion of the fire-affected sites. Moreover, they underline the importance of the establishment and regeneration of Genisteae species to outcompete pioneer pyrophytic species, favoring the restoration of the area’s potential natural vegetation

Including vegetation dynamics in an atmospheric chemistry-enabled general circulation model: linking LPJ-GUESS (v4.0) with the EMAC modelling system (v2.53)

Central to the development of Earth system models (ESMs) has been the coupling of previously separate model types, such as ocean, atmospheric, and vegetation models, to address interactive feedbacks between the system components. A modelling framework which combines a detailed representation of these components, including vegetation and other land surface processes, enables the study of land–atmosphere feedbacks under global climate change. Here we present the initial steps of coupling LPJ-GUESS, a dynamic global vegetation model, to the atmospheric chemistry-enabled atmosphere–ocean general circulation model EMAC. The LPJ-GUESS framework is based on ecophysiological processes, such as photosynthesis; plant and soil respiration; and ecosystem carbon, nitrogen, and water cycling, and it includes a comparatively detailed individual-based representation of resource competition, plant growth, and vegetation dynamics as well as fire disturbance. Although not enabled here, the model framework also includes a crop and managed-land scheme, a representation of arctic methane and permafrost, and a choice of fire models; and hence it represents many important terrestrial biosphere processes and provides a wide range of prognostic trace-gas emissions from vegetation, soil, and fire. We evaluated an online one-way-coupled model configuration (with climate variable being passed from EMAC to LPJ-GUESS but no return information flow) by conducting simulations at three spatial resolutions (T42, T63, and T85). These were compared to an expert-derived map of potential natural vegetation and four global gridded data products: tree cover, biomass, canopy height, and gross primary productivity (GPP). We also applied a post hoc land use correction to account for human land use. The simulations give a good description of the global potential natural vegetation distribution, although there are some regional discrepancies. In particular, at the lower spatial resolutions, a combination of low-temperature and low-radiation biases in the growing season of the EMAC climate at high latitudes causes an underestimation of vegetation extent. Quantification of the agreement with the gridded datasets using the normalised mean error (NME) averaged over all datasets shows that increasing the spatial resolution from T42 to T63 improved the agreement by 10 %, and going from T63 to T85 improved the agreement by a further 4 %. The highest-resolution simulation gave NME scores of 0.63, 0.66, 0.84, and 0.53 for tree cover, biomass, canopy height, and GPP, respectively (after correcting tree cover and biomass for human-caused deforestation which was not present in the simulations). These scores are just 4 % worse on average than an offline LPJ-GUESS simulation using observed climate data and corrected for deforestation by the same method. However, it should be noted that the offline LPJ-GUESS simulation used a higher spatial resolution, which makes the evaluation more rigorous, and that excluding GPP from the datasets (which was anomalously better in the EMAC simulations) gave 10 % worse agreement for the EMAC simulation than the offline simulation. Gross primary productivity was best simulated by the coupled simulations, and canopy height was the worst. Based on this first evaluation, we conclude that the coupled model provides a suitable means to simulate dynamic vegetation processes in EMAC.