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The influence of climate on the radial growth of Scots pine in the northern Scandinavia
Tomeš, Miroslav ; Treml, Václav (advisor) ; Šefrna, Luděk (referee)
The presented master's thesis deals with the influence of climate on the radial growth of Scots pine in the northern Scandinavia. Trees growing at the polar treeline are sensitive to environmental changes, and therefore their wood is used to study growth responses to ongoing climate change. During the period of the 20th and the beginning of the 21st century, air temperatures and precipitation sums were correlated with tree rings and dendroanatomical data of Scots pine from northern Finland. It was found that the widths of the tree rings had a slightly increasing trend during the observed period. Within the framework of the correlation relations, the controlling influence of the air temperatures of the current July on annual increments was confirmed. Thanks to the higher temperatures of the summer season, wider tree rings were formed. In addition, May and summer precipitation have been shown to be important for the final width of the tree ring. The currently often discussed problem of decoupling the tree ring chronology curve from rising summer temperatures ("divergence problem") was not clearly observed in this work. In order to evaluate the dendroanatomical parameters, the tree rings of the studied individual were divided into four sectors with a similar number of cells in the radial file. During...
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Zhodnocení výskytu a růstu jmelí bílého (Viscum album) na vybrané lokalitě
Halfar, Jan
European mistletoe (Viscum album L.) is an evergreen semi-parasitic plant, with a wide host range of both deciduous and coniferous trees. As a native species, this plant is widespread throughout Europe. The first part of this paper is aimed as a literature review, which includes a description of European mistletoe, a general description of its occurrence and its effect on host woody plants. The second part focuses on a survey of a selected area between the villages of Bělá and Chuchelná (Opava district), where the degree of infestation of individual trees, the species of infested trees and their age are assessed. At the same time, the number of mistletoe plants, their distribution in the crown, and in the oldest mistletoe specimens their age and haustorium length were determined at three sites in the forest area belonging to the Lesy města Brno a.s. In this work it was found that mistletoe occurred mainly on Scots pine at site 1, but was also found on silver fir and small-leaved linden. At site 1, mistletoe began to invade pine after the age of 30. Mistletoe in young stands grew mainly on trees with the greatest high growth and in the upper part of the crown. On the basis of these results, I recommend to concentrate the management of mistletoe-infested forest stands on tree age above 30 years during planned thinning and to actively remove infested individuals from the stand. Changing the species composition of forest stands in favour of mistletoe-resistant species is also one of the ways to prevent the spread of mistletoe in threatened areas. At site 2, the age of the largest mistletoe shrubs ranged from 9 to 18 years. The longest measured haustorium was 18 cm in length and was measured on mistletoe at 17 years of age. From the measurement results, a relationship between mistletoe age and haustorium length was found. Knowing the haustorium length is important in the context of tree protection when performing branch pruning. Therefore, based on the results of this work, I recommend removing infested branches at a minimum distance of 30 cm from the mistletoe shrub, especially for older mistletoes.
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Assessment of drought response in local Scots pine ecotypes using anatomical, biochemical, and fluorescence stress markers.
Štěpánová, Kristýna ; Lhotáková, Zuzana (advisor) ; Stejskal, Jan (referee)
Global climate change and associated global warming is already a problem for temperate forest ecosystems and will continue to exacerbate the problem in the coming decades. Many species will have to adapt to a multifactorial combination of stresses, with increases in average air temperature, frequency and intensity of precipitation increasing drought episodes and drought-affected areas will enlarge. It is necessary to find ways to help the landscape cope with these intensifying phenomena. The possibility of planting suitable tree species that can manage water efficiently and survive even in periods of intense water scarcity is an option. The drought tolerance of trees is related to their phenotypic plasticity and ecotypic differentiation. Scots pine (Pinus sylvestris L.) is characterised by modest ecological demands on the environment and climate of the habitat, is phenotypically plastic and relatively drought resistant. The objectives of this study were 1) to evaluate and compare the response of different Scots pine ecotypes to drought stress due to reduced water availability using anatomical, biochemical, and fluorescence indicators of physiological status, and 2) to determine the biochemical phenotype of selected genotypes within a local Scots pine ecotype in a seed orchard in terms of...
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Scots pine climate-growth response in the topographically complex landscape of the Kokořínsko region
Fišer, Petr ; Treml, Václav (advisor) ; Šefrna, Luděk (referee)
The extensive Scots pine Pinus sylvestris forests in topographically complex landscape of the Kokořínsko region in the Czech Republic are a suitable area for investigating how trees react differently to climate factors depending on local site conditions. Individual habitats are characterized by specific conditions which can influence a wide range of growth factors. It is therefore important to understand these differences also from the point of view of ongoing climate change, which threats forest ecosystems in central Europe. The relatively dry environment of the highly permeable sandstone landscape is vulnerable to increasing drought, which will increase the stress of local Scots pine population. Samples from 20 sites divided into 4 categories of northern slopes, southern slopes, plateaus and valley bottoms are supposed to sufficiently represent variability of the local terrain. Correlation of tree-ring chronologies with climate variables as well as PCA analysis revealed that the greatest differences are between plateaus and valley bottoms. In case of highly exposed plateaus, drought seems to be the most important limiting factor, whereas at the valley bottoms temperatures at the turn of winter and spring are the main controlling factor. Signifficant differences between northern and southern...
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Geographical characteristics of extreme growth depressions of Scots pine in Central Europe
Mík, Milan ; Treml, Václav (advisor) ; Rybníček, Michal (referee)
The presented diploma thesis studies extreme growth depressions of Scots pine (Pinus sylvestris L.) in Central Europe. Examination of significant growth anomalies (pointer year analysis) is one of the methods, which investigates the reactions of forest stands to the ongoing climate change. Dendrochronological data was obtained from Czechia (23 sites) and Slovakia (4 sites). The main hypotheses of the thesis states that the extreme growth depressions relate to climatic anomalies, hence they can be explained geographically. The objectives were to 1) create a Cropper values chronology for each site which describes growth extreme depressions; 2) explain climatic causes of negative Cropper values for each site; 3) define geographical predispositions of a spatial distribution of extreme growth depressions; 4) spatially interpolate extreme growth depressions. The calculation of Cropper values was based on a normalisation in a moving window method with a 13-year window size and the input data detrended by a 50-year cubic smoothing spline. Created chronologies were correlated with monthly climate data (temperatures, precipitation, SPEI). Geographical predispositions of the spatial distribution of growth depressions were calculated using a hierarchical cluster analysis. The cluster analysis was also applied...
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Development and interpretation of site tree-ring chronology of Pinus sylvestris
Mašek, Jiří ; Treml, Václav (advisor) ; Šefrna, Luděk (referee)
The presented bachelor thesis deals with the study of climatic factors that influence the growth of the pine (Pinus sylvestris) in the locality near Rabštejn nad Střelou. The primary objective was to determine the limiting factors of tree growth and to perform dendroclimatic reconstruction. For this purpose, samples were taken at the site and local chronologies were created using various standardization methods. Using the correlation coefficients, limiting growth factors were determined, and reconstruction by regression and scaling was performed based on the highest correlation. The results showed a strong relationship of rings width to rainfall and humidity conditions, especially in the summer months and in various seasons from April to August. Most of the chronologies also showed the positive influence of February temperatures. Observed signature rings in many cases are well responsive to various climatic anomalies. For the most correlated variable, dendroclimatic reconstruction was calculated for the period 1850 - 2016 when the chronology was reliable. The reconstructed average rainfall corresponds well with the Klementinum climate line and other rainfall reconstructions.
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Remnant of forest at the transition from Late Glacial period to Holocene: dendroecological and palaeobotanical reconstruction
Moravcová, Alice ; Šamonil, Pavel (advisor) ; Rybníček, Michal (referee)
The remains from a sub-fossil pine forest burried in layers of peat deposits at the northern edge of the CHKO Křivoklátsko in the Central Bohemia is completely unique findings for the area of the Czech Republic. It offers new opportunities for palaeoenvironmental reconstruction and related climate changes during the Late Glacial and early Holocene epoch. The methods of dendrochronology and radiocarbon dating were used to date subfossil trees. The results of radiocarbon dating determined the existence of the forest in the period approximately 12,000 to 10,300 cal yr BP. The dendrochronological analyses revealed two continuous floating chronologies. The chronology RD4, which is long 200 years, originates from the Younger Dryas. The chronology RD6, 300 years long, originates from the Preboreal. The growth dynamics of the forest were reconstructed on the basis of the tree- ring analysis. Hydrological regime has been identified as a major disturbancy factor that influenced the growth of trees. This has been evident from synchronous phase depressions in the growth of synchronized tree-ring series. The high water table was the main cause of their extinction. This was in concordance with the results of macrofossils analyses. The effect of hydrological regime was largely influenced by microsite differences...
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