Search

The aim of the studies was to evaluate the usefulness of the microscopic features of wood in characterising the climatic conditions of a period for which only proxy data are available. Samples were taken from historical wood from Koronowo collegiate church and from a living Scots pine tree growing in the Toruń-Wrzosy site. All measurements were performed using ImageJ software. The dendroclimatological analysis was carried out in the program DendroClim2002. The results show a correlation between the microscopic features of wood and climatic conditions. For the period 1951-2000 the maximum optical density of pine wood depends on average May air temperature and June precipitation, with correlation coefficients of -0.32 and -0.29, respectively. A similar correlation was found for mean maximum and minimum temperatures in May; -0.35 and -0.37, respectively. Additional correlations between selected meteorological elements and the maximum optical density of the wood were found using 30-year moving averages and moving intervals. [ABSTRACT FROM AUTHOR]

European beech Fagus sylvatica and Sessile oak Quercus petraea are reaching the north-eastern limits of their natural ranges in northern Poland. According to the projected changes in potential ranges in this region, climatic conditions for both species until 2080 will remain stable. On the other hand, a decrease in the vitality of mature trees and a reduction in their radial growth are currently observed. To understand these contradictory findings, we monitored the cambial activity in both species during two vegetation seasons. 2015 was characterized by a negative water balance, while 2017 was wet. This provided an opportunity to compare how the xylogenesis proceeds in diffuse-porous beech and ring-porous oak during contrasting in the summer precipitation seasons. The forming annual increments were sampled with Presler borer at variable time intervals depending on the leaf phenological phases. The cores were prepared using a sledge microtome and double-stained with safranin and astra blue. Observations of the phases of wood formation and measurements of the width of the forming increments were analysed on the microslide digital images. Differences in the dates of the phenological phases were analysed using Two-Way ANOVA, while the dynamics of the formation of annual increments were fitted to the Single and Double Gompertz function for beech and oak, respectively. The beginning of vessel formation started earlier in both seasons compared to previous studies. Inter-seasonal differences in the duration of spring phenological phases were insignificant for both species, while inter-species differences were significant due to physiological diversity between diffuse-porous beech and ring-porous oak. In dry 2015, cambial activity ceased sooner in both species than in 2017. Differences between oak and beech were insignificant in both years, but statistically significant disparities existed within each species due to varying in precipitation seasons. Rainfall significantly elongated the duration of cambial activity and caused wider tree-rings. According to our study, despite predicted maintaining their climatic niche, both species, situated at the north-eastern cooler range boundary, are expected to produce wood at a lower rate due to the projected warmer central European climate with increased heatwaves and summer droughts. [ABSTRACT FROM AUTHOR]

Highlights • The climatic conditions of Central Europe favor primarily IADFs in earlywood and transition zone. • Frequency of IADFs in Norway spruce is mainly caused by site-related climatic conditions. • Temperature and precipitation sensitivity determines the variability between Norway spruce provenances in the IADFs frequency. • Frequency of IADF E and E + depends on climatic distance between provenance trials and provenance origin. Abstract Understanding the growth pattern of trees of various provenances in response to climatic conditions provides information on the adaptive potential of trees. Intra-annual density fluctuations (IADFs) are anatomical markers of variations in wood density within the annual wood increment. Latewood-like cells within earlywood, resulting from severe drought during spring and early summer, express the structural adaptation of the wood tissue to unfavorable climatic conditions. In this study, we used two 40-year old IUFRO provenance trials of Norway spruce located in the western and north-eastern Poland to i) determine the effect of provenance on the IADF frequency and ii) to define the climatic factors determining the formation of IADF. Three highly polymorphic nuclear microsatellites are used to determine the differentiation among provenances in particular between the northern and southern Polish distribution area. Our results demonstrate that the frequency of all types of IADFs is determined by the growing conditions, and only the IADFs in the transition zone are determined by provenance origin. The highest variability between provenances in response to climatic differences was observed for IADF in transition zone, where temperatures and rainfall of spring and early summer differentiated northern and southern provenances. Moreover, the IADF frequency was influenced by drought, thereby differentiating provenances in terms of their sensitivity to severe conditions. Furthermore, environmental differentiation of climate-growth reaction was expressed by a stronger impact of climatic conditions observed in the western than in the northeastern trial site. The results of this study confirm the dependency of climate related changes in wood characteristics on provenance origin. Therefore, density fluctuations seem to be an appropriate adaptive trait for selecting Norway spruce provenances with varying degree of drought sensitivity. [ABSTRACT FROM AUTHOR]

Tradeoffs between intra and interspecific distances of individual plants determine the spatial distributions of local plant communities and small‐scale community assembly. Here we use an individual based approach and null model standardization to compare intra‐ and interspecific nearest neighbour distances of plant ramets as well as mean differences in functional trait expression to nearest heterospecifics within local communities of temperate forest understorey plants in northern Poland. We found a general tendency towards clustered intraspecific and segregated interspecific ramet distributions. Spatial distribution patterns of understorey plants differed considerably between two nearby forest sites that mainly differed in the age structure of trees. Individuals of clonal species tended to have significantly smaller intraspecific and larger interspecific nearest neighbour distances than seed dispersing species. Our results indicate a major influence of dominant plant species on the spatial distributions of subdominants. Trait expressions related to plant growth (specific leaf area and leaf mass) and reproduction (seed mass) were significantly segregated in comparison to the spatial distribution of conspecific individuals and less so in comparison to heterospecific individuals. We argue that spatially explicit analyses of plant community assembly need to consider respective distributions of important traits and that the tradeoffs of contrasting trait distributions trigger small scale plant community composition and species distributions. We present a general framework for the analysis of plant community assembly based on the spatial distributions of individual plants and functional traits. [ABSTRACT FROM AUTHOR]

Research Highlights: This study used a 99-year time-series of daily climatic data to determine the climate-growth relationship for Scots Pine (Pinus sylvestris L.) growing in Northern Poland. The use of daily climatic data improved the calculated climatic response of the trees. Background and Objectives: It was hypothesised that daily temperature and precipitation data would more precisely identify climate–growth relationships than monthly data. We compared our results to a previous study conducted in the 1990s that utilised monthly precipitation and temperature data. Materials and Methods: The chronology construction and data analyses were performed using CooRecorder, CDendro and R packages (dplR, treeclim, dendrotools). Forty-nine cores from 31 trees were included in the final chronology. Results: The precipitation and temperature of March had the strongest influence upon ring-widths. Despite a statistically significant correlation between monthly temperature and ring-widths, reduction of error (RE) and coefficient of efficiency (CE) statistics confirmed that daily data better describe the effect of climate on tree rings width than monthly data. Conclusions: At this site, the growing season of Scots pine has changed with the observed association with precipitation now starting as early as February–March and extending to June–July. [ABSTRACT FROM AUTHOR]