Can we distinguish between tree-ring eccentricity developed as a result of landsliding and prevailing winds? Consequences for dendrochronological dating

The aim of our study was to compare patterns of tree-ring eccentricity developed in Nor-way spruce trees as a result of landsliding with the one caused by the prevailing wind (in 2 study sites), and with the normal growth of trees (in 2 reference sites). We sampled 20 trees per study site and 10 per reference site. Two cores were taken from each tree (120 cores in total) from the upslope and downslope, windward and leeward sides of stems. Ring widths measured on opposite sides of stems were compared using the method of percent eccentricity index. Graphs of the index obtained for individual trees were analysed. Statistical indicators were calculated for a percent eccentricity in-dex. Disturbance events were dated and the response index was calculated. The results show that the patterns of eccentricity developed as a result of the prevailing winds and due to landsliding differ from one another and from the reference sites. The results suggest that the impact of the prevailing wind on tree growth is more severe than the impact of landsliding. The difference may result from the slow-moving character of the landslide under study. The results, however, indicate that wind impact should be taken into account in dendrogeomorphic research and that the impact of mass movements should be considered in dendroecological studies on wind

Radiocarbon dated late-glacial Scots pine (Pinus sylvestris L.) chronology from Central Poland

Dendrochronologically dated wood of subfossil trunks of trees presents the basic material used at construction of the calibration curve. In the last years numerous studies have been aimed at construction of chronologies covering the late-glacial period (Kaiser et al. 2012). At present, Koźmin (Dzieduszyńska et al. 2014) and Kwiatków (Kolska Basin, Central Poland) proved to be very perspective sites, in which wood from the end of Allerød and Younger Dryas was recognized. A level of organic deposits with so-called ‘fossil forest’ was encountered within the late-Vistulian terrace of the low valley of the Warta river</p

Dendrochronological dating as the basis for developing a landslide hazard map – An example from the Western Carpathians, Poland

Most landslide hazard maps are developed on the basis of an area’s susceptibility to a land-slide occurrence, but dendrochronological techniques allows one to develop maps based on past land-slide activity. The aim of the study was to use dendrochronological techniques to develop a landslide hazard map for a large area, covering 3.75 km2. We collected cores from 131 trees growing on 46 sampling sites, measured tree-ring width, and dated growth eccentricity events (which occur when tree rings of different widths are formed on opposite sides of a trunk), recording the landslide events which had occurred over the previous several dozen years. Then, the number of landslide events per decade was calculated at every sampling site. We interpolated the values obtained, added layers with houses and roads, and developed a landslide hazard map. The map highlights areas which are poten-tially safe for existing buildings, roads and future development. The main advantage of a landslide hazard map developed on the basis of dendrochronological data is the possibility of acquiring long se-ries of data on landslide activity over large areas at a relatively low cost. The main disadvantage is that the results obtained relate to the measurement of anatomical changes and the macroscopic charac-teristics of the ring structure occurring in the wood of tilted trees, and these factors merely provide in-direct information about the time of the landslide event occurrence

Scots pine (pinus sylvestris L.) growth suppression and adverse effects on human health due to air pollution in the upper Silesian Industrial District (USID), southern Poland

Air pollution emissions were not continually monitored in the Upper Silesian Industrial District (USID), southern Poland, and data is only available for the last 20 years. Long-lasting and severe tree ring reductions in pines growing 5–20 km north of the USID area recorded particularly high levels of air pollution emissions in the period 1950–1990. Especially high amounts of reductions and many missing rings were found in the period 1964–1981. At the same time, pines growing 60 km west of the USID do not record deep ring reductions; this proves that the phenomenon is of a regional nature. Increases in infant mortality and lung, bronchial, and tracheal cancer morbidity rates among males were also recorded in the USID during periods of high air pollution. Infant mortality rates increased several years after the tree ring reductions. Therefore, it may be possible to use tree ring reductions as an early indicator of the occurrence of adverse effects on human health

Dendrogeomorphological analysis of landslide activity along the planned S-69 road in the Węgierska Górka municipality (Beskid Śląski Mountains, S Poland)

Our dendrogeomorphological analysis was completed for 4 landslides, situated in the municipality of Węgierska Górka in the Beskid Śląski Mountains in Southern Poland. The local landslides pose a direct threat to the newly designed S-69 expressway running through the north-western part of the municipality. The research material consisted of 127 samples, collected with the use of a Pressler increment borer, from three species of coniferous trees (Norway spruce, Scots pine, and Silver fir). The landslide activity periods were identified on the basis of the splitting of the dendrochronological curves representing the upslope and downslope parts of the tree trunks. The largest number of the studied trees indicated reactions to substrate mass movements in 1964, 1971, 1972, 1984, 1994, 1997, 1998, and 2010. The detailed locations of the sampled trees allowed us to reconstruct the activities of particular landslide sections in time. We identified the fact that parts of the landslides located downslope of the planned road S-69 are more active than parts of the same landslides located above it on the slope. Geological conditions in the studied area favour landslide activity while precipitation is the main triggering factor of landslides

Assessment of landslide hazard from tree-ring eccentricity and from compression wood - a comparison

We have compared maps of landslide activity and hazard, developed with the use of two different dendrochronological indicators: tree-ring eccentricity and reaction (compression) wood. The maps were prepared based on 125 Norway spruce (Picea abies L. Karst.) trees growing at 44 sampling points, distributed over an area of 3.75 km2. In general, the two maps show similar patterns of landslide activity. However, tree-ring eccentricity yielded a greater number of dated events (246) compared to compression wood (129). Besides the differences in the absolute values of dating results, the general landslide activity and hazard zonation based on both disturbances are similar. Both growth disturbances develop as a result of stem tilting. Eccentricity develops after slight tilting, while compression wood is developed when tilting is more significant. Because of the differences in the strength of disturbing factors, which cause the development of compression wood and growth eccentricity, the best approach would be to combine the results of dating obtained from the two methods. The dendrochronological analysis of tree growth disturbances (eccentric growth and compression wood) is a promising approach for determining landslide hazards in forested mountain areas and can be applied in spatial management

Zanieczyszczenie atmosfery przez zakłady przemysłowe położone w północnej części Wyżyny Śląskiej zapisane w przyrostach rocznych sosny zwyczajnej

Pines growing close to Tarnowskie Góry Chemical Plant and Miasteczko Śląskie Zinc Foundry produced reduced tree rings from 1950 to 1990 when compared with pines growing 60 km from the factories. Tree ring reductions occurred concurrently with the operation of the chemical plant and zinc foundry. Ring widths of the sampled pines are inversely proportional to the sulphur dioxide emissions from the Miasteczko Śląskie Zinc Foundry and the volume of production in the Tarnowskie Góry Chemical Plant. This demonstrates that the growth of trees was suppressed by emissions from the factories. Pines growing close to the zinc foundry started to produce reduced rings in 1965 and tree rings were very heavily suppressed in the 1970s. Reductions were noted from the time when the zinc foundry started to operate up until the present day. Reduced rings in 2000–2009 are produced by pines growing close to the zinc foundry and also those growing at a distance of 60 km from it. This indicates that ring reductions in 2000–2009 are not necessarily the effect of pollution emissions by the foundry. Tarnowskie Góry Chemical Plant emitted atmospheric pollution as early as 1925–1930 and as a result large tree ring reductions and many missing rings were identified in cores collected from pines growing close to the chemical plant. Tree ring reductions and missing rings occurred from 1955 to 1985 in pines growing close to the chemical plant. Pines have started to produce relatively wide rings since 1985 when the volume of production in the chemical plant rapidly decreased. This indicates that the plant reduced harmful emissions to the atmosphere from this date onwards