The effects of in-channel wet-pit mining is nowadays widely discussed in terms of negative influence of the created pits on the river ecosystem and fluvial processes. The pits induce an alteration of ...natural flow or sediment transport. This paper describes the post-mining channel recovery observed in a relatively short time in a gravelly sand bed lowland river. The study was based on repeated bathymetry of the channel and grain size analyses of bed material taken from the mining area and its surrounding upstream and downstream pit. We also use calculations of possible bedload sediment movement in the studied river reach. We noticed that the excavation pit exceeded the maximum depth of 8.8 m in 2014 and, immediately after the end of mining, the bedload started to infill the pit. The bathymetric measurements in 2019 indicated that the process of pit infill was completed after five years, though the former pit is refilled with material finer than the natural bedload observed in the discussed river reach, and consists mainly of sand. The studied process of pit infilling runs continuously, even during the annual average water stages.
Although variations in building activity are a useful indicator of societal well-being and demographic development, historical datasets for larger regions and longer periods are still rare. Here, we ...present 54,045 annually precise dendrochronological felling dates from historical construction timber from across most of Europe between 1250 and 1699 CE to infer variations in building activity. We use geostatistical techniques to compare spatiotemporal dynamics in past European building activity against independent demographic, economic, social and climatic data. We show that the felling dates capture major geographical patterns of demographic trends, especially in regions with dense data coverage. A particularly strong negative association is found between grain prices and the number of felling dates. In addition, a significant positive association is found between the number of felling dates and mining activity. These strong associations, with well-known macro-economic indicators from pre-industrial Europe, corroborate the use of felling dates as an independent source for exploring large-scale fluctuations of societal well-being and demographic development. Three prominent examples are the building boom in the Hanseatic League region of northeastern Germany during the 13th century, the onset of the Late Medieval Crisis in much of Europe
c
. 1300, and the cessation of building activity in large parts of central Europe during armed conflicts such as the Thirty Years’ War (1618–1648 CE). Despite new insights gained from our European-wide felling date inventory, further studies are needed to investigate changes in construction activity of high versus low status buildings, and of urban versus rural buildings, and to compare those results with a variety of historical documentary sources and natural proxy archives.
•Climate-growth relationships of treeline trees and shrubs were explored.•Trees featured a closer coupling with summer temperatures than shrubs.•Shrubs were more affected by microsite conditions than ...trees.•Recent growth acceleration of trees was steeper than that of shrubs.•Trees at their leading edge react to increasing temperature stronger than trailing-edge shrubs.
Although there are ample data on growth trends and climate growth relationships of trees from the leading edge of their distribution at treeline, information from the neighbouring trailing edge of the vegetation belt dominated by alpine shrubs is missing. We expected trees at their upper limit to exhibit unambiguous temperature limitation with a clearly positive growth response to recent warming. On the other hand, shrubs at the lower limits of their distribution and because of their low-stature are assumed to be less constrained by temperature, with ambiguous growth trends as compared to trees. We collected tree-ring series from sites with co-occurring Norway spruce (Picea abies) and Mountain pine (Pinus mugo) in four mountain ranges of Central Europe (the High Tatras, the Hrubý Jeseník Mts, the Krkonoše Mts and the Bavarian Alps), assembled a suite of tree-ring chronologies containing either long-term trends or high-frequency variability, and compared climate-growth relationships and growth trends between spruce and pine. Our results show that in all areas under study, growth patterns of spruce statistically differ from those of pine. The growth of spruce is characterized by a tight relationship with June–July temperatures, maximum correlations ranging between 0.5 and 0.6. The climatic signal in tree-rings of pine is also characterized by a significant influence of summer temperature, albeit weaker than that observed in spruce (mostly between 0.3 and 0.4). All sites exhibited increasing growth trends for spruce since the 1980s; trend slopes for pine were either less positive (Hrubý Jeseník and Krkonoše Mts) or negative (High Tatras). To conclude, the growth of spruce at its leading edge clearly resembled temperature-limited growth with corresponding recent growth acceleration, while the response of low-stature mountain pine to warming was weaker because of its tight coupling with microsite conditions and the location at the trailing edge of its distribution.
The role of future forests in global biogeochemical cycles will depend on how different tree species respond to climate. Interpreting the response of forest growth to climate change requires an ...understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of common tree species. We constructed a new network of 310 tree‐ring width chronologies from three common tree species (Quercus robur, Pinus sylvestris and Fagus sylvatica) collected for different ecological, management and climate purposes in the south Baltic Sea region at the border of three bioclimatic zones (temperate continental, oceanic, southern boreal). The major climate factors (temperature, precipitation, drought) affecting tree growth at monthly and seasonal scales were identified. Our analysis documents that 20th century Scots pine and deciduous species growth is generally controlled by different climate parameters, and that summer moisture availability is increasingly important for the growth of deciduous species examined. We report changes in the influence of winter climate variables over the last decades, where a decreasing influence of late winter temperature on deciduous tree growth and an increasing influence of winter temperature on Scots pine growth was found. By comparing climate–growth responses for the 1943–1972 and 1973–2002 periods and characterizing site‐level growth response stability, a descriptive application of spatial segregation analysis distinguished sites with stable responses to dominant climate parameters (northeast of the study region), and sites that collectively showed unstable responses to winter climate (southeast of the study region). The findings presented here highlight the temporally unstable and nonuniform responses of tree growth to climate variability, and that there are geographical coherent regions where these changes are similar. Considering continued climate change in the future, our results provide important regional perspectives on recent broad‐scale climate–growth relationships for trees across the temperate to boreal forest transition around the south Baltic Sea.
A tree‐ring network from European beech, Scots pine and oak trees from around the south Baltic Sea was compiled to examine the relationship between tree growth and climate. Our findings indicate tree growth is influenced by warming winter climate and summer moisture availability in northern temperate forests. Furthermore, spatial analysis suggests that there are geographical patterns in similar growth responses to climate and that these responses can be unstable through time.
The Sudety Mts. form a chain of mountains in the South of Poland and during the last 200 years were subjected to strong industrial and agricultural pressure. The records of these human-induced ...changes are stored in natural archives like lake sediments. For the comprehensive study, three sediment cores taken from Mały Staw Lake (Sudety Mts.) were analyzed for the concentration of K, Na, Mn, Fe, Cu, Mg, Zn, Cd, Cr, Ni, Pb and radioactivity of
137
Cs and
210
Pb. As a result of the studies, the bathymetry map was developed and the sources of solid material supplied to the lake were identified. The geochronology studies of the cores were performed using
210
Pb method, to evaluate model of time changes in the sediment. Radioactivity of
210
Pb
uns
(determined indirectly by
210
Po) ranged from 1051 ± 64 to 12 ± 8 Bq kg
−1
. The
137
Cs radioactivity was determined directly by gamma spectrometry and varied from 525 ± 37 Bq kg
−1
for top layers to 9.80 ± 5.40 Bq kg
−1
for the bottom of the core. Two characteristic peaks of
137
Cs radioactivity related to the global fallouts after nuclear weapons testing and the Chernobyl accident were observed and used to confirm
210
Pb dating method. Chemometrics analysis of the chosen metal’s concentrations combined with sample dating showed distinct imprint of human activity on the studied area.
Growth divergence – i.e. the expression of divergent growth trends of neighboring trees – has certain implications for dendrochronological research, for instance in the context of climate ...reconstructions but also in terms of estimating net ecosystem productivity. Thus, understanding the underlying mechanisms is essential to extend our fundamental dendroecological knowledge. In this context, the Picea genus plays an important role since several of its species were reported to exhibit growth divergence. Here, we investigate a well sampled Norway spruce (Picea abies (L.) Karst) data set for growth divergence comprising ring-width and Blue Intensity measurements from seven sites on Babia Góra Mountain, at the border between Poland and Slovakia. By means of Principal Component Gradient Analysis, inter-series correlations, and climate growth relationships, we are able to show that I) Norway spruce on Babia Góra expressed growth divergence since the 1970s, II) the definition of groups increased the strength of population signals and the stability of climate-growth relationships, and III) Blue Intensity appeared as a more robust proxy for environmental conditions. We discuss soil heterogeneity, genetics, and air pollution as possible underlying mechanisms, thereby indicating further research avenues to obtain a better understanding of growth divergence.
Key message
Decadal growth variability of Norway spruce increases with elevation. Recent temperature sensitivity and growth enhancement are limited to trees growing in the zone adjacent to ...timberline.
Growth trends and climate responses of forest trees along elevational gradients are not fully understood. A deeper insight is, however, fundamental for predicting ecosystem functioning and productivity under future climate change. Supplementary to the effects of elevation and regional provenance on tree growth are sample depth, uneven representation of sample age and varying site conditions. Furthermore, there is only a limited number of studies addressing growth changes along elevational gradients, while at the same time applying tree-ring standardization methods that are sensitive to trend preservation. Here, we introduce 12 novel tree-ring width chronologies of Norway spruce (
Picea abies
L. Karst.) from four elevational belts encompassing montane forests and the local timberline in three regions in East-Central Europe between 15° and 19°E. Each chronology is characterized by sufficient sample replication and a comparable age structure between 1906 and 2010. Tree growth near timberline revealed substantial medium-frequency variability and sharply increasing ring widths since the 1980s. Medium-frequency growth variability of lower elevation trees was, however, relatively small, and growth rates over the last decade were either stable or even decreased. During the last four decades, Norway spruce from higher elevations exhibited a reduced response to autumn temperatures preceding ring formation. In contrast, trees from the lower-montane zone increased their sensitivity to drought during the same time. Our results emphasize not only different but also instable growth trends and climate responses of forest trees along altitudinal gradients, which should be considered in future forest management strategies.
Annually resolved and absolutely dated Maximum Latewood Density (MXD) and Blue Intensity (BI) measurements are frequently used for reconstructing summer temperature variability over the last ...centuries to millennia. A direct comparison of the outcome of both methods using similar material is needed due to how quickly this method is being adopted. The application of slightly different measuring systems (hardware) and analysis tools (software) in tandem with different wood samples and preparation procedures further challenges any straightforward assessment. Here we process 26 Norway spruce samples from the upper timberline in the Polish Tatra Mountains with the six most frequently used MXD and BI applications. Although offset is found in the raw MXD and BI data (0.04–0.13 g/cm3 and 0.45–1.58 dimensionless blue intensity), interannual and longer-term fluctuations are significantly (p < 0.01) positively correlated between all MXD and BI time-series. Our results emphasize the potential of faster and cheaper, as well as overall more user-friendly techniques to generate reliable MXD surrogates for high-frequency dendroclimatological studies. Although the correlations between MXD and BI were lower than within MXD and BI, the results of growth-climate response performed for both proxies show only marginal differences. The obtained level-offset further questions the suitability of joining different density surrogates for developing long-term composite chronologies to reconstruct low-frequency climate variability.
The work contains quantitative analysis of differentiation of altitudinal position and sinuosity of two lines determining the course of forest limit, i.e. timberline and treeline within Babia Góra ...Mt. (1725 m a.s.l.) homoclinal flysch ridge (the Western Carpathians). The course of the empiric timberline was delimited basing on aerial photographs with details from spatial data of Aerial Laser Scanning conducted in 2012. On the N slope, the course of timberline is exclusively conditioned by natural factors, whereas on the S slope this line was shifted downwards as a result of sheep and cattle grazing (however it has shown progression for the last 80 years). In the course of theoretical treeline conditioned by macrotopography and local climate, the mass-elevation effect is visible, and on the N slope, additionally, a sub-summit downward shift (the Diablak effect) occurs. The sequence of natural factors, according to their positive or negative influence on timberline and treeline courses was determined.
Floods represent a common process in Tatra Mountain streams and may cause flood risk in the valleys of the Tatra foreland. Dealing with the hazards and risks caused by floods requires a detailed ...analysis of the frequency and magnitude of past and recent events. However, the Polish Tatra region is characterized by a scarcity of data on past floods in general and on systematic peak discharge in particular. In this study, we performed a paleohydrological analyses in four high-gradient mountain streams using scarred trees as paleostage indicators. We couple two-dimensional hydraulic modelling in a highly-resolved topographic environment (LiDAR data) with an important spatiotemporal data set of scars on trees to investigate (i) the magnitude of unrecorded major floods of the twentieth century, (ii) the effect of variability in geomorphic tree positions on the peak discharge reconstruction, and (iii) the impact of reconstructed events on the results of flood frequency analyses. The data set is based on a total of 55 scarred trees and allows peak discharge reconstruction of 16 major floods covering the last 113years. Results suggest that trees growing in straight stream reaches or in the inner side of channel bends would be better candidates for peak discharge reconstructions than trees located on the outer side of channel bends or growing in overbank sections with dense vegetation cover. The largest reconstructed flood is dated to 1903 with an estimated peak discharge of 115.9±59.2m3s−1, and larger-than-today floods are found to have occurred at Strążyska and Łysa Polana in the first half of the twentieth century. The inclusion of our results into the flood frequency analyses suggests that flood hazards might have been underestimated by up to 25.5% in the case of a 100-year flood in Strążyski Stream. In that sense, our findings will be useful for the design of future strategies dealing with flood risks in the foreland of the Polish Tatra Mountains.
•In mountain streams, the scarcity of records hampers the analysis of flood process.•Paleohydrology allows us to estimate peak discharges of past flood events.•We reconstructed past flood events in four streams in the Tatra Mountains.•Larger events have been reconstructed for the first half of the twentieth century.•Our results have implications for flood hazard analysis in the region.
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