National Repository of Grey Literature 66 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Measured and modelled fluxes of tropospheric ozone in mountainous Norway spruce forest
Juráň, Stanislav ; Zapletal, Miloš ; Večeřa, Zbyněk ; Cudlín, Pavel ; Urban, Otmar
Tropospheric ozone fluxes (O3) were measured in Norway spruce forest at Bily Kriz, Czech Republic by eddy covariance technique. Within-canopy concentration gradient was measured by APOA-370 analysers (Horiba, Japan) in 7m, 25m and 30m above ground. Fluxes of O3 were modelled from the concentration gradient by applying Inverse Lagrangian Transport Model (Raupach, 1989). Next, O3 fluxes were modelled on the basis of resistent analogy. Ozone flux measured by eddy covariance technique amounted up to 1.19 nmol m-2 s-1 on daily average and the lowest -0.75 nmol m-2 s-1. Studied forest stand was net sink for ozone in 7.14 mmol m-2 per day (=0.343 g m-2 per day). The highest ozone emission peaked during noon hours, suggesting closure of stomata due to low air temperature and ozone production due to sufficient radiation. Both models proved to be imprecise when compared to measured data in autumn-winter transition period.
Research on inflence of SO2 and NOx on spruce growth
Hruška, Jakub ; Oulehle, Filip ; Kolář, Tomáš
Radial growth of Norway spruce (Picea abies) in Krušné and Jizerské Mts.responded qiuckly on the decline of SO2 and NOx emissions and S deposition. At the end of 1990´s it was equal to growh measured before the period of high emissions. The best correlation was founded with ambient SO2 concentrations, then with S atmosperic deposion and less important correlation was found with soil chemistry as it is correlated with deposition levels. At present there is no evidence of influence of SO2 and NOX on decline of radial growht. Observed decline in last decade is most probably attributed to climatic conditions.
Laboratory/Field Spectroscopy and Remote Sensing Image Data for Vegetation Studies
Červená, Lucie ; Kupková, Lucie (advisor) ; Pavelka, Karel (referee) ; Müllerová, Jana (referee)
Dominant vegetation species of two structurally and functionally different montane ecosystems were studied by means of laboratory and field spectroscopy and remote sensing image data: (1) a homogeneous human-influenced evergreen coniferous forest represented by a Norway spruce forest in the Krušné hory Mountains and (2) a heterogeneous natural ecosystem of a relict arctic-alpine tundra in the Krkonoše Mountains with predominance of grasses. The first part dealing with the Norway spruce forest is especially focused on the methods of laboratory spectroscopy. The assessment of Norway spruce stands on a regional and a global scales requires detailed knowledge of their spectral properties at the level of needles and shoots in the beginning, but ground research is very time-demanding. Open spectral libraries could help to get more ground-truth data for subsequent analysis of tree species in forests ecosystems. However, the problem may arise with the comparability of spectra taken by different devices. The present thesis focuses on a comparability of spectra measured by a field spectroradiometer coupled with plant contact probe and/or two integrating spheres (Paper 3) and proves the significant differences in spruce needle spectra measured by the contact probe and integrating sphere, spectra of...
Vliv environmentálních faktorů na přežívání smrku ztepilého v oblastech rozpadu horských smrčin v důsledku lýkožrouta smrkového
In the first part of this study, I attempted to classify and describe factors, that could increase the resistence of Norway spruce against a bark beetle attack. I tested the impact of selected factors on the survive of Norway spruce in the forest decay compared to live forest in the second part of this study.
The state of the Natural Regeneration in Bavarian Forest National Park, 10 Years after the Total Death Parent Stands
Červenka, J. ; Wild, Jan ; Svoboda, M. ; Kopecký, Martin ; Macek, Martin ; Brůna, Josef ; Zenáhlíková, J.
The presented research is focused on the state of natural regeneration (Norway spruce and Rowan), 10 years after total death of parent stands in the core untouched part Bavarian Forest National Park. The 16 permanent plots 40m x 40m are located on the southeast of Bavaria. We determined exact height, size of the last height increment, condition and species of trees. Number of saplings were counted and classified by heights. These number ranged from 53 to 17276 saplings per hectare. The spruce species composition was 96.7%. The height structure of spruce shows that almost 73% found spruce trees reached heights greater than 0.5 m. The average height increment increased with increasing height of saplings. This paper presents state of natural regeneration in mountain spruce forests in Bavarian Forest National Park without the human influence in summer 2010, 10 years after total death of parent stands.
Application of imaging spectroscopy in monitoring of vegetation stress caused by soil pollutants in the Sokolov lignite basin
Mišurec, Jan ; Kupková, Lucie (advisor) ; Pavelka, Karel (referee) ; Homolová, Lucie (referee)
Forests can be considered as one of the most important Earth's ecosystems not only because of oxygen production and carbon sequestration via photosynthesis, but also as a source of many natural resources (such as wood) and as a habitat of many specific plants and animals. Monitoring of forest health status is thus crucial activity for keeping all production and ecosystem functions of forests. The main aim of the thesis is development of an alternative approach for forest health status based on airborne hyperspectral data (HyMap) analysis supported by field sampling. The proposed approach tries to use similar vegetation parameters which are used in case of the current methods of forest health status assessment based on field inspections. It is believed that importance of such new methods will significantly increase in the time when the planned satellite hyperspectral missions (e.g. EnMap) will move into operational phase. The developed forest health monitoring approach is practically demonstrated on mature Norway spruce (Picea abies L. Karst) forests of the Sokolov lignite basin which were affected by long-term coal mining and heavy industry and therefore high variability of forest health status was assumed in this case. Two leaf level radiative transfer models were used for simulating spectral...
Modulation of ozone flux in a mountain spruce forest under different cloud cover
Juráň, Stanislav ; Fares, S. ; Urban, Otmar
Ozone (O3) fluxes were modelled from a concentration gradient in a Norway spruce forest at the Bílý Kříž experimental station for years 2012–2016. Daily and seasonal O3 depositions were calculated separately for days with cloudy, partly cloudy, and clear sky conditions. The hypothesis that overcast conditions modulate O3 flux in the forest ecosystem via controlled stomatal conductance is tested. Indeed, the highest stomatal conductance followed by the highest O3 deposition was found during partly cloudy and cloudy sky conditions in all seasons.
Tree-ring chronologies of Norway-spruce on west-east longitudinal gradient in the mountain ranges of central Europe
Ponocná, Tereza ; Treml, Václav (advisor) ; Kolář, Tomáš (referee) ; Vejpustková, Monika (referee)
The Earth's climate system has recently experienced substantial warming which likely impacts temperature-limited communities close to their distribution margins. The alpine treeline ecotone represents upper distributional limit of montane/subalpine forests. This biogeographic boundary relies mainly on decreasing temperature with increasing elevation. Surprisingly the response of treeline ecotone to ongoing warming has varied a lot and the reasons of this variability are poorly understood. The aim of this dissertation thesis is the assessment of growth trends and tree ring response of Norway spruce (Picea abies[L.] Karst.) to climatic oscillations at treelines and montane forests of East-Central Europe. This dissertation deals with both inter-regional and intra-regional (aspect, elevation) variability of tree growth. The presented results are based on an extensive data set of growth curves for almost 1400 trees. All study sites revealed close relationship between tree ring widths and growing season temperatures as well as the temperatures of October preceding to ring formation season. The main site-dependent differences in growth trends and temperature responses were attributed to elevation, the effect of aspect was relatively less significant. At treelines between the Krkonoše Mts. and Nízké Tatry...
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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