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Tree uprooting may distinctly affect landscape dynamics and slope denudation. Little is known, however, about the corresponding soil redistribution rates (erosion and accumulation) on either a long‐term (millennia; 10Be) or a short‐term (decades; 239+240Pu) scale. We determined these rates in a well‐investigated forest reserve (Zofinsky primeval forest, Czech Republic) using complementary techniques: nuclides in soils and tors to derive short‐ to long‐term rates and monitoring data (43 years) of repeated tree censuses using tree uprooting data. Temporal trends of soil erosion rates were obtained by dating the timing of exhumation (10Be) of tors. The average long‐term denudation rates were about 30–40 t km−2 yr−1. It seems that these rates varied over time with probably a maximum during the Pleistocene/Holocene transition (58–91 t km−2 yr−1). 239+240Pu activities in the soils identified soil redistribution rates of 50 to >100 t km−2 yr−1 for the last decades and agree with results from the tree uprooting monitoring (<92 t km−2 yr−1). In‐situ 10Be in soils gave similar denudation rates (58–76 t km−2 yr−1). Meteoric 10Be provided a mean residence time of a soil particle of 33–100 ka supporting the measured average long‐term erosion rates. Soil aggregates indicated stable physical conditions meaning that soil mass redistribution occurs only sporadically. It seems that the main driving factors of denudation changed over time. An erosion peak at the Pleistocene/Holocene transition (climate change) seems likely but needs further proof. Over the last few millennia, tree uprooting seems the main driver of soil erosion. [ABSTRACT FROM AUTHOR]

Fagus sylvatica (European beech) populations in Central Europe are currently expanding their dominance in many forest types. In this study we focused on the spatio-temporal dynamics of beech recruitment as a mechanism for successful expansion. Specifically we investigated: (1) the developmental trend of the tree community composition and spatial pattern in an unmanaged Picea abies-F. sylvatica forest over 37 years, (2) the pattern of decrease in clustering along increasing tree size gradient of beech, and (3) the spatial patterns of beech regeneration in relation to gap-makers. The study was conducted in the Žofín Forest Dynamics Plot, which is part to the Smithsonian Institution’s Forest Global Earth Observatory (ForestGEO) as the research plot representing European natural mixed temperate forests. To quantify these dynamics, we used the stem map of trees with DBH ⩾ 10 cm carried out in 1975, 1997, 2008 and a census of trees with DBH ⩾ 1 cm from 2012 to calculate recruitment, growth, mortality and, from those vital rates, population change. Various types of the pair correlation function were applied to the data to describe the tree density variability over time. Our analyses revealed a trend of increasing F. sylvatica representation at the expense of P. abies and Abies alba over the 37 years. Increased clustering of F. sylvatica trees with DBH ⩾ 10 cm correlated with new recruits at plots where F. sylvatica replaced declining P. abies . On the other hand, the decrease in F. sylvatica clustering at some plots was likely due to strong intra-specific competition. The analysis of the spatial patterns of F. sylvatica individuals along DBH gradient 1–9 cm showed a trend of increasing clustering up to 5 m distance. F. sylvatica saplings to 4 cm of DBH were positively spatially correlated with other conspecific individuals, although at larger sizes (DBH 7–9 cm), this relationship reversed to a negative correlation. Analysis of relationships between saplings and gap-makers did not reveal a clear pattern. We concluded that without a coarse-scale disturbance capable of restructuring the community, F. sylvatica will become the only dominant tree species in this forest type. F. sylvatica gradually replaces P. abies through its space occupation strategy because its recruits are already present before a canopy disturbance. Our results indicate that F. sylvatica saplings can grow up to 4 cm DBH under a closed canopy, but require a canopy disturbance to advance to a larger size class. [ABSTRACT FROM AUTHOR]

European beech ( Fagus sylvatica ) increases its dominance in various forest types in Central Europe. In this context we investigated a very exceptional process, in which beech have been partly outcompeted by sycamore maple ( Acer pseudoplatanus ) in unmanaged forest without severe disturbances. Main research questions were as follows: (i) How did the spatial patterns of beech and sycamore develop, and can these patterns be described by known spatial models?; (ii) What were the spatial relationships between beech and sycamore?; (iii) Does the spatial relationship of advance regeneration to gap-makers differ for the two species?; (iv) Did the presence of a road influence the spread of the sycamore population? The study was conducted in beech-dominated forest Žákova hora in the central part of the Czech Republic which has been left to spontaneous development for 85 years. We studied long-term forest dynamics using stem position maps of trees with DBH ⩾ 10 cm carried out in 1974, 1995 and 2011. We used standard methods for calculating recruitment, mortality and population change. Various types of the pair correlation function were applied to describe the development of tree spatial patterns. Our results showed that sycamore regenerated in the close vicinity of other conspecific trees. Sycamore recruits were not spatially associated to individual gap makers. Sycamore individuals had a highly clustered distribution, and the number of individuals grew mostly through the increasing of existing clusters. We successfully fitted the Matérn cluster process for sycamore spatial patterns. The radius of the model cluster ranged between 6 and 16 m. By contrast, beech recruits were negatively correlated to older conspecific trees and showed independence or positive correlation to sycamore veterans. The vicinity of the road significantly promoted sycamore recruitment (opposed to the beech). If the sycamore expansion is connected with the vicinity of the road and thickening of existing sycamore clusters only, as our results indicate, then it can be spatially and temporally limited process. [ABSTRACT FROM AUTHOR]

Abstract: The long-term development of stand characteristics and tree spatial patterns (TSP), their mutual relation, and linkage to site and tree species were studied in the Boubín primeval forest (protected since 1858). Surveys were carried out in 1851, 1961/1964, 1972, 1984/1989, 1996 and 2010 on one to six research plots sized 0.58–1.00ha. To see how results from these surveys could be generalized, results were also compared with whole-area data sets (46ha) from 1972 to 2010. The proportion of Abies alba continually decreased, from 20% in 1851 to 2–3% in 2010. This decrease started no later than at the beginning of the 20th century. In contrast, the proportion of Fagus sylvatica slightly increased. The sum of dead and living wood volume was stable during the 159year period, with deviations of only up to 5%. From 1961/64 to 2010, the number of living trees continually decreased, but the mean-tree volume and volume of dead wood increased. The distribution of dead wood always differed from the distribution of living trees. A random TSP was always most common, which seems to be typical for this type of forest. This was true even when A. alba was gradually forced out from the stand structure. Nevertheless, the pronounced decrease of A. alba found during the 1961/64 survey compared with 1851 was reflected in a tendency towards clustering, as gaps from A. alba dieback gradually closed. In these gaps, competitive pressure was lower, resulting in more clustered distributions. Regular distribution was recorded only rarely. F. sylvatica maintained a random or clustered TSP over long periods, depending on site conditions. On water-affected plots, it had a consistently higher tendency towards clustering. The only step change in TSP occurred due to Hurricane Emma in 2008. Otherwise, the most marked TSP changes over time were found for Picea abies, in which there was a gradual trend from clustered to random, connected with a decreasing number of individuals. The main reason for the decline of A. alba and the decreased number of living trees from 1961/64–2010 was the on-going effect of a high stock of red deer at the turn of the 19th and 20th centuries. The decreasing trend in the number of living trees showed no marked change, even 60years after the game pressure was strongly reduced. However, the vertical structure became increasingly homogenized due to the long-term absence of severe abiotic and/or biotic disturbances. [Copyright &y& Elsevier]

Abstract: Current knowledge of the within-site variability of major stand structural features in beech dominated natural forests is limited. Numerous studies have used just several small plots for characterizations of natural stands, but this may lead to generalizations based on unreliable results. This study shows how major stand structural features vary at the local scale, and how suitable sampling may reflect this variability. Stem position maps of three natural forests in the Czech Republic (Zofin 71ha, Salajka 19ha and Zakova hora 17ha) were used. Each vector stem position map representing all live and dead trees with DBH≥10cm was intensively analyzed using square sample plots of different sizes (10×10m; 20×20m; 30×30m; 50×50m; 100×100m; 140×140m and 200×200m). Basic statistics (mean, standard deviation, coefficient of variation, min., and max.) were calculated for every plot size and each of six major stand features: density, basal area and volume of living trees, volume of course woody debris, total volume and proportion of course woody debris in total volume. As expected, the local relative variability of major stand structural features decreased with increasing plot size. For particular stand features, the observed trend was expressed by significant regression models (y = a × x b ) with high coefficients of determination across all study sites. The results further show that even hectare-to-hectare values are still highly variable; e.g. the volume stock of living trees can range from 474 to 1049m3/ha within one study site. Hence, single samples of 1ha can be poorly representative. We also calculated the minimal number of plots and total sampled area required for estimations of major stand features to within 20% (±10%) of the mean with 95% confidence for particular plot sizes. It appears that plot sizes between 0.01 and 0.09ha would be the most efficient for sampling the above-mentioned variables in European beech-dominated natural forests. [Copyright &y& Elsevier]

Abstract: A detailed historical survey was made to assess the impact of humans on fir–beech forests in the northern Carpathians. Research findings are compared with results from repeated tree layer measurements in eight of the most well-preserved reserves of fir–beech stands in the region. Documentary evidence is provided showing that the historical and contemporary spontaneous development of fir–beech stands throughout the northern Carpathians is identical. The replacement of beech by fir occurred predominantly in the period from the 15–18th centuries, primarily due to grazing and litter raking. Starting in the 19th century, fir was replaced predominantly by beech under the influence of changing social conditions, since the dieback of the “grazing” fir generation had not yet been completed. Air pollution damage and other factors in the fir dieback were only secondary accelerating phenomena. These changes of tree species cannot be interpreted as the natural rotation of two beech generations within the life cycle of one fir generation, as has been the previous explanation. The development is rather a linear trend induced by man, which has occurred simultaneously throughout the northern Carpathians. The current dynamics of spontaneous development are affected by the high stock of hoofed game and by the absence or reduced numbers of predators. [Copyright &y& Elsevier]

• Canopy trees altered forest floor by litter and deadwood production and uprooting. • Deep beech litter accumulations prevented regeneration of spruce, but not of beech. • Deadwood and uprooting mounds were the best microsites for spruce regeneration. • Soil wetness became more limiting for beech regeneration in larger size classes. • Canopy trees of both species showed the ability to support their own regeneration. Natural regeneration of European beech (Fagus sylvatica) and Norway spruce (Picea abies) plays a crucial role in the future of many European mountain forests. It is affected by various soil and stand-related factors whose relative importance, especially in mixed stands, is still not known. In this study, we assessed the importance of stand composition, soil wetness, disturbances and different microsites and seedbeds for regeneration of beech and spruce in a mixed old-growth mountain forest. We also focused on how the effects of these factors change as regeneration gets older. We sampled all regeneration in 563 plots from different microsite types (deadwood, intact soil, treethrow pits and mounds), distinguishing three seedbeds (mosses, beech litter, bare substrate) for seedlings. We used soil survey and tree census data with generalized linear mixed models and variance partitioning to identify the main factors driving tree regeneration and their relative importance. Although beech was slightly less abundant in the canopy than spruce, it strongly outnumbered spruce in regeneration. Beech regeneration showed an affinity for beech litter-rich microsites and drier soils, while spruce was more common on deadwood and moister soils and its response to the seedbed was microsite-specific. The regeneration of both species was positively related to the proportion of their own species in the canopy, but more so in seedlings than in older regeneration cohorts, where soil wetness was more important. The overall pattern of tree regeneration thus resulted from a complex interplay between site conditions and their alterations by current and former generations of canopy trees through the creation of new microsites (deadwood, uprooting mounds) or litter production. Where beech regeneration is not suppressed by excess soil wetness, it is much more successful than spruce due to its shade tolerance and ability to be established in the beech litter that dominates the forest floor. On the other hand, spruce regeneration is mostly restricted to elevated microsites with lower litter accumulation, such as deadwood and treethrow mounds. Our results indicate that both species exhibit an ability to modify their environment in favor of their own regeneration, but under current conditions, beech is more successful than spruce and can be expected to increase its dominance in the future. [ABSTRACT FROM AUTHOR]

The diameter growth of a tree reflects the success of that tree in competition. We investigated patterns of Fagus sylvatica diameter growth in the Žofín Forest Dynamics Plot, which is part of Smithsonian's Forest Global Earth Observatory as a research plot representing European natural mixed temperate forests. We focused primarily on the spatial patterns of beech diameter growth from the viewpoint of the most successful individuals in different ontogenetic stages. We analyzed the reaction of trees along a gradient of disturbance intensity as well as the effects of neighborhood competition. We used stem maps of trees with a diameter at breast height (dbh) ≥ 10 cm carried out in 1997 and 2012. Various types of the pair correlation function were applied to the data to describe the tree density variability. Tree spatial pattern analyses were performed on six 1.5‐ha square plots. Our results show an increasing trend of general increment growth in the interval between dbh 10 cm and dbh 40 cm. Average increment first peaked between dbh 40–42 cm with values higher than 5 mm/year, after which the absolute average increment slightly decreased and stagnated; dbh increment again increased only after dbh 79 cm, but with a much wider range of confidence intervals. An analysis of the variability in diameter growth at intermediate spatial scales showed that disturbance events influence diameter growth differently in connection with dbh. Diameter growth in thinner trees was strongly positively correlated with disturbance intensity, while disturbance had no effect on the variability in diameter growth in larger trees. The spatial pattern of elite‐growth recruits differed from the generally clustered pattern of recruits, with mutual negative interactions up to 2 m. Elite‐growth small‐sized trees (dbh 10–19 cm) showed a positive association with dead individuals in the same size category. In contrast, elite‐growth medium‐sized trees (dbh 20–39 cm) had no positive associations at all. At the same time, negative correlations with canopy beeches were observed across all categories. In conclusion, current tree spatial patterns of trees and their diameter growth are the results of multiple interactions accumulated over the long term with high inertia. [ABSTRACT FROM AUTHOR]