The aim of this study was to examine the effects of pruning the root system and different doses of nitrogen fertilization on the height and root collar diameter of 2-year-old beech seedlings (Fagus sylvatica L.). This research was conducted in the forest nursery Muchów (Jawor Forest District, regional directorate of State Forests in Wrocław) and two different pruning treatments (no pruning and at 12 cm depth) and nitrogen fertilization doses (25 and 50 kg×ha−1) were applied. Results from an ANOVA showed statistically significant differences between the two pruning treatments (p = 0.000) as well as for the interaction of both treatment factors (p = 0.019). Root collar diameter correlated with seedling height, both of which were significantly different for the two pruning treatments (p = 0.000). No statistically significant impact by the nitrogen fertilization doses on seedling height could be observed (p = 0.125). To conclude, we found that it is reasonable to reduce the doses of nitrogen fertilization to half the recommended amount, 25 kg×ha−1, if the root system is not pruned during the second growth year. Seedlings that do receive pruning should be fertilized using the recommended nitrogen doses.
Three of the most frequently used sigmoidal growth curves from the Richards family are the logistic model, Gompertz model and Richards model. They are used in the analysis of organismal growth over time in many disciplines/studies and were proposed in many parameterisations. Choosing the right parameterisation is not easy. The correct parameterisation of the model should take into account such parameters that are useful to describe the analysed growth phenomenon and are biologically relevant without additional calculations. In addition, each parameter of the model only affects one shape characteristic of each growth curve, which makes it possible to determine standard errors and confidence intervals using statistical software.
Growth curves in germination dynamics studies should provide information on topics such as the length of the lag in onset of germination, the maximum germination rate and, when it occurs, the time at which 50% of seeds will germinate and the final germination proportion. In this article, we present three parameterisations of the logistic, Gompertz and Richards models and indicate two parameterisations for each model, corresponding to the above-mentioned issues. Our proposition is parameterisation by taking into account the maximum absolute growth rate. Parameterisations indicated as useful for germination dynamics are characterised by the fact that each parameter has the same meaning in every model, so its estimates can be compared directly amongst the models. We also discussed the goodness-of-fit measures for nonlinear models and in particular measures of nonlinear behaviour of a model’s individual parameters as well as overall measures of nonlinearity.
All described models were used to study the dynamics of the epicotyl emergence of pedunculate oak. After checking the close-to-linear behaviour of the studied model parameters and by taking into account the criteria of model selection (AICc of each growth curve and the residual variance [RV]), the best model describing the dynamics of epicotyl appearance of pedunculate oak was the Richards curve.
Evolutionary processes lead to the survival of individuals best adapted to local environment. This gives rise to allele polymorphism and genetic diversity of populations. Isoenzyme proteins, which are the product of gene expression, are an effective tool for tracking these changes. On the other hand, the reproductive potential of a given population can be assessed based on its ability to produce viable and efficiently germinating seeds. The present results combine molecular analyses of isoenzyme proteins with anatomical and morphological studies of Scots pine seeds (Pinus sylvestris L.). The study was conducted in 6 populations that are characteristic of this species occurrence range in the country. The results confirm the correlation between seed weight and embryo size. They also show a population from northeastern Poland had a higher effective number of alleles and seed with lower germinative energy and capacity. There was genetic homogeneity in all except for the population from Woziwoda, which was significantly different based on the Fst test. The genetic characteristics of Scots pine from Woziwoda may be associated with the lower levels of rainfall that occur there during the growing season. The results improve our knowledge of Scots pine variability and contribute to the discussion of the impact of local environment on genetic variability.
The purpose of this study was to determine the growth variability of four provenances of Picea abies on experimental plots in the Wyszków Forest District, central Poland. The experiment was established as a system of random blocks with four repetitions per block. We selected 48 trees from each provenance and the increment cores were colected from sample trees. Standard measurements of the width of annual increments were performed using the WinDendro software. Raw data was then indexed and subject to dendroclimatic analyses based on the average monthly temperatures and precipitation of the period from 1969 to 2012. Furthermore, the COFECHA software was used to check the consistency of the data and to determine the pointer years. High data consistency as well as growth variability of particular provenances in response to climatic conditions was observed. The results obtained here will allow for an improved selection of populations best suited for growing in the climate of central Poland
The aim of the study was to determine the vulnerability of selected silver fir populations to damage from late frost in the climatic conditions of south-eastern Poland. To determine the vulnerability of apical and lateral shoots to damage caused by late frosts, we observed four test plots in 2009 and 2014, each containing progenies of selected seed stands. Our statistical analyses were based on a model incorporating the following variables: site, year, type of frost damage, population as well as the possible interaction between these variables. Significant differences between the populations were found in terms of their sensitivity to damage from low temperature occurring during the growth period. Furthermore, we indirectly demonstrated differences in the severity of late frost on the experimental plots, as well as the intensity and variability of late frost shoot damage. Based on these results, we divided the studied populations into two groups of low (EF, KRA1 and NAR) and high (LES2 and BAL2) sensitivity to late frost damage.