- Research in Plant Ecophysiology and impact of global change on ecosystemsedit
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Leaf area index (LAI) and radiation use efficiency (RUE) are two key crop parameters widely used to estimate the biomass production and carbon accumulation. However, long term LAI and RUE has rarely been studied on arable land in fast... more
Leaf area index (LAI) and radiation use efficiency (RUE) are two key crop parameters widely used to estimate the biomass production and carbon accumulation. However, long term LAI and RUE has rarely been studied on arable land in fast growing poplar short rotation coppice (SRC) and cereal crops. For better understanding and improving the potential of biomass accumulation of poplar SRC on arable land, and cereal crops (winter wheat and spring barely), we evaluated and compared the development of LAI and RUE in SRC poplar culture, winter wheat and spring barley. Poplar SRC culture was based on hybrid poplar clone J-105 (Populus nigra x P. maximowiczii) grown in a high-density (9216 trees ha-1). Poplar plantation was established in 2002, winter wheat (Triticum aestivum) was sowed in October 2011 and spring barley (Hordeum vulgare) was sowed in April to May 2012. Our results demonstrate an enhanced LAImax and RUE values with an increase in the growing season (GS) in SRC poplar. However, maximum RUE value was found in cereal crops as compared to SRC poplar culture (woody crop). LAI and RUE may be considered as a good estimator of biomass in woody and cereal crops.
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Stem wood density (SWD) of young Norway spruce trees (Picea abies [L.] Karst.) growing at ambient (A variant, 350 µmol(CO2)/mol) and elevated (E variant, A + 350 µmol(CO2)/mol) atmospheric CO2 concentration inside of the glass domes with... more
Stem wood density (SWD) of young Norway spruce trees (Picea abies [L.] Karst.) growing at ambient (A variant, 350 µmol(CO2)/mol) and elevated (E variant, A + 350 µmol(CO2)/mol) atmospheric CO2 concentration inside of the glass domes with adjustable windows was estimated after six and eight years of the cultivation. Stand density of two subvariants (s – sparse with ca 5,000 trees/ha and d – dense with ca 10,000 trees/ha) and thinning impact (intensity of 27%) on SWD and its variation along the stem vertical profile were investigated. After six years of CO2 fumigation, stems of sparse subvariant had about 10% lower values of SWD comparing to dense ones, although the difference was not statistically significant. In 2004 (two years after thinning), the SWD values were higher in all subvariants along the whole stem vertical profile. This increase was more obvious in E variant (about 6% in d subvariant and only 3% in s subvariant). The highest increase of SWD values was found in Ed subvar...
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Accurate wind analyses using six wind classes and twelve splitting directions were done to deeply evaluate wind conditions on Štítná CzeCOS’s ecosystem station in the Czech Republic. The analysis brings information about contribution of... more
Accurate wind analyses using six wind classes and twelve splitting directions were done to deeply evaluate wind conditions on Štítná CzeCOS’s ecosystem station in the Czech Republic. The analysis brings information about contribution of different part of the research-forested area to the measurement of CO2 exchange between the studied ecosystem and atmosphere. Štítná station is located inside of a forest composed of Fagus sylvatica with age 114 years and the forest can be harvested sometime forward. Total of 82 % of the wind contributions speed are in the range of 1.0 - 6.0 m s-1 and the major accumulation of winds comes from SE (9 %), SSE (17 %) and S (14 %); 13 % were calm periods. The obtained information will be useful for evaluate the conditions of the use of the eddy covariance technique in the research area.
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The measurements of soil CO2 efflux in a Norway spruce (Picea abies [L.] Karst.) forest stand are reported for a 6-month period (from May 1st to October 26th 1999). Forest floor CO2 efflux was measured at four positions using a portable... more
The measurements of soil CO2 efflux in a Norway spruce (Picea abies [L.] Karst.) forest stand are reported for a 6-month period (from May 1st to October 26th 1999). Forest floor CO2 efflux was measured at four positions using a portable infra-red gas analyser (LI-COR), operating as a closed dynamic system and connected to a portable soil chamber. Soil CO2 efflux was measured 3–4 times per month. Soil temperature at a depth of 5 cm was recorded during the whole period with an interval of ten minutes. An exponential regression was used to describe the relationship between soil temperature and soil CO2 efflux. On the basis of this relationship Q10 values were calculated. The averaged value of Q10 for the studied Norway spruce forest stand was 3.74.
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Bud phenology and shoot elongation growth were monitored on Norway spruce (Picea abies [L.] Karst.) trees grown inside glass domes with adjustable windows for six years under ambient (355 µmol CO2∙mol–1) and elevated (700 µmol CO2∙mol–1)... more
Bud phenology and shoot elongation growth were monitored on Norway spruce (Picea abies [L.] Karst.) trees grown inside glass domes with adjustable windows for six years under ambient (355 µmol CO2∙mol–1) and elevated (700 µmol CO2∙mol–1) atmospheric CO2 concentrations CO2. Each treatment consisted of two stand densities – sparse (5,000 trees∙ha–1) and dense (10,000 trees∙ha–1). The age of spruce trees was 10 years at the beginning of the experiment.Elevated CO2 slightly accelerated the consequential bud germinating phases and it significantly induced shoot elongation growth, especially of sun-exposed shoots in a stand with sparse density. This accelerated growth lasted one to three weeks after full bud development in E compared to A. At the end of the growing season the total shoot length did not show any differences between the treatments. We supposed that limiting nitrogen supply to needles slowed down subsequent shoot elongation growth in E treatment. Nevertheless, faster shoot g...
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This investigation examined the effects of two different carbon dioxide concentrations ([CO
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Leaf area index (LAI) is an important determinant of biomass production and yield of short rotation bio-energy plantation. An accurate measurement of LAI is critical for quantifying light interception and penetration within the canopy,... more
Leaf area index (LAI) is an important determinant of biomass production and yield of short rotation bio-energy plantation. An accurate measurement of LAI is critical for quantifying light interception and penetration within the canopy, and subsequently understanding its influence on the stand carbon and energy balance. The aim of the current study is validation of the Sunscan Plant Canopy Analyzer which serves as an indirect method for the evaluation of the seasonal patterns of LAI, relation between LAI and above ground woody dry biomass and to determine the specific leaf area in short-rotation poplar hybrid clone J-105 (Populus nigra × P. maximowiczii) in uncoppiced (1st rotation) and coppiced (2nd rotation), respectively. LAI was measured in uncoppiced and coppiced by two different methods using indirect (SunScan Plant Canopy Analyzer) and direct (litterfall collection). Sunscan Plant Canopy Analyzer was compared against litterfall collection (only way to retrieve the actual LAI)....
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Marková I., Janouš D., Marek M.V.: Total net radiation of the mountain Norway spruce stand at The presented paper reports results from the comprehensive measurements carried out in the mountain Norway spruce stand at the experimental... more
Marková I., Janouš D., Marek M.V.: Total net radiation of the mountain Norway spruce stand at The presented paper reports results from the comprehensive measurements carried out in the mountain Norway spruce stand at the experimental study site of Bílý Kříž (the Czech Republic). Determination of total net radiation during the growing season is an important information used in an ecophysiologi-cal research of the growth processes of a spruce stand under study and it is one of the input value for a description of atmospheric carbon allocation. Four components (incoming and outgoing shortwave radiation and incoming and outgoing long-wave radiation) of the total net radiation were measured and analyzed separately and from these values total net radiation were calculated. Linear relationship between the total net radiation and incoming shortwave radiation was confirmed for the studied stand the whole growing season. Mean daily sums of total net radiation related to the mean daily sums of...
The radiation exchange drives the plant ecosystems energy balance and provides the energy for photosynthesis, transpiration and plant growth. The investigation on net radiation and its component during vegetation season in relation to the... more
The radiation exchange drives the plant ecosystems energy balance and provides the energy for photosynthesis, transpiration and plant growth. The investigation on net radiation and its component during vegetation season in relation to the clearness index and sun elevation in a cultivated 31-year-old mountain spruce [Picea abies (L.) Karst.] stand is presented. Downward short-wave radiation – S d (incident on the spruce stand was the main part of the short-wave radiation balance during the whole growing season (April–October) 2008. The S d amount is seasonally variable factor determined by the duration of solar shine and the atmosphere transmissivity. Obtained value of net radiation (R n ) and downward short-wave radiation (S d ) ratio amounts to 0.61 on average during the growing season 2008 documenting the importance of the downward short-wave radiation in the net radiation of investigated spruce stand.
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Globally, forests provide several functions and services to support humans’ well-being and the mitigation of greenhouse gases (GHGs). The services that forests provide enable the forest-dependent people and communities to meet their... more
Globally, forests provide several functions and services to support humans’ well-being and the mitigation of greenhouse gases (GHGs). The services that forests provide enable the forest-dependent people and communities to meet their livelihood needs and well-being. Nevertheless, the world’s forests face a twin environmental problem of deforestation and forest degradation (D&FD), resulting in ubiquitous depletion of forest biodiversity and ecosystem services and eventual loss of forest cover. Ghana, like any tropical forest developing country, is not immune to these human-caused D&FD. This paper reviews Ghana’s D&FD driven by a plethora of pressures, despite many forest policies and interventions to ensure sustainable management and forest use. The review is important as Ghana is experiencing an annual D&FD rate of 2%, equivalent to 135,000 hectares loss of forest cover. Although some studies have focused on the causes of D&FD on Ghana’ forests, they failed to show the chain of causa...
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The relationship between mineral nutrition and the rate of photosynthesis is very complex. In brief, a certain rate of photosynthesis is necessary to maintain the mineral element absorption by the roots, and conversely, a certain rate of... more
The relationship between mineral nutrition and the rate of photosynthesis is very complex. In brief, a certain rate of photosynthesis is necessary to maintain the mineral element absorption by the roots, and conversely, a certain rate of mineral absorption is necessary to maintain photosynthesis (R. Brouwer, 1962). In the case of nitrogen nutrition this relationship is very clear. The RuBP carboxylase/oxygenase (RuBPCO), the main enzyme of photosynthetic CO2 fixation, contains the majority of leaf nitrogen (J.K. Bolton, R.H. Brown, 1980). Nitrogen supply affects the RuBPCO content and activity (K. Winter et al., 1982). The total volume of leaves is reduced under nitrogen deficiency (J. Pazourek, L. Natr, 1981), and hence, the transport of CO2 into chloroplasts is affected, which is evident from the change of the mesophyll and stomatal resistances to CO2 transfer. The nitrogen deficient plants exhibit a greater portion of mitochondrial respiration in light than do normal plants.
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Abstract Forests provide many supporting, regulating and cultural services. Extensive environmental changes have resulted in a substantial loss or degradation of forest ecosystem services (ES). Unclear interactions of climate-change... more
Abstract Forests provide many supporting, regulating and cultural services. Extensive environmental changes have resulted in a substantial loss or degradation of forest ecosystem services (ES). Unclear interactions of climate-change phenomena make it difficult to estimate forest ES. Research on interactive effects of climate change and air pollution has become a central issue in forest science during the past decade. Climate change in interaction with air pollution brings novel combinations of severity and timing of multiple stresses, which may significantly affect many forest ES. The aims of the present chapter are to identify basic concepts of evaluating ES with a focus on forest ES, to provide physiological and ecological bases for their evaluation, and to discuss the interactive effects of climate change and air pollution on forest ES based on selected tree physiological functions. Climate regulation mediated by deforestation-induced changes in the hydrological cycle is discussed. Adaptive governance and communication to the public promotes sustainable forest–multi-stakeholder collaboration. A case study is presented evaluating selected ES in a forest–agricultural landscape in the Czech Republic on the basis of monitored energy, water and material flows estimation. From this study, it is apparent that future research must include multi-factorial anthropogenic and natural interactions of climatic changes and air pollution in conjunction with sustainable forest ES provisions. Sustainable forest management is an essential tool for reducing the vulnerability of forests to environmental change.
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Research Interests: Botany, Forestry, Photosynthesis, Plant Biology, Biology, and 15 moreCanopy, Oak, Relative Humidity, Primary Production, Mathematical Model, Forestry Sciences, Forest ecosystem, Deciduous, Microclimate, Air Temperature, Carpinus Betulus, Forest Floor, Photosynthetic Rate, Deciduous Forest, and Respiration Rate
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In order to understand the effect of phytotoxic tropospheric ozone (O3) on terrestrial vegetation, we quantified the impact of current O3 concentration ([O3]) on net ecosystem production (NEP) when compared to the conditions of the... more
In order to understand the effect of phytotoxic tropospheric ozone (O3) on terrestrial vegetation, we quantified the impact of current O3 concentration ([O3]) on net ecosystem production (NEP) when compared to the conditions of the pre-industrial era. We compared and tested linear mixed-effects models based on [O3] and stomatal O3 flux (Fsto). The managed ryegrass–clover (Lolium perenne and Trifolium pratense) mixture was grown on arable land in the Czech Republic, Central Europe. Values of [O3] and Fsto were measured and calculated based on resistance analogy, respectively, while NEP was calculated from eddy covariance CO2 fluxes. We found the Fsto-based model more precise when compared to measured NEP. High Fsto was found even at low [O3], while broad summer maximum of [O3] was not necessarily followed by significant NEP decline, due to low soil water content leading to a low stomatal conductivity and Fsto. Comparing to low pre-industrial O3 conditions, current levels of O3 result...
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The strong effects of climate change are expected to negatively impact the long-term resilience and function of forest ecosystems, which could lead to changes in forest carbon balance and productivity. However, these forest responses may... more
The strong effects of climate change are expected to negatively impact the long-term resilience and function of forest ecosystems, which could lead to changes in forest carbon balance and productivity. However, these forest responses may vary with local conditions and forest types. Accordingly, this study was carried out to determine gross primary productivity (GPP) sensitivity to changes in environmental parameters. Central European beech (at Štítná) and spruce species (at Bílý Kr̆íz̆ and Rájec), growing under contrasting climatic conditions, were studied. The comparative analyses of GPP were based on a five-year-long dataset of eddy covariance fluxes during the main growing season (2012–2016). Results of forest GPP responses with changes in environmental factors from a traditional Stepwise multiple linear regression model (SMLR) were used and compared with Random forest (RF) analyses. To demonstrate how actual GPP trends compare to potential GPP (GPPpot) courses expected under nea...
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The occurrence of extreme drought poses a severe threat to forest ecosystems and reduces their capability to sequester carbon dioxide. This study analysed the impacts of a central European summer drought in 2015 on gross primary... more
The occurrence of extreme drought poses a severe threat to forest ecosystems and reduces their capability to sequester carbon dioxide. This study analysed the impacts of a central European summer drought in 2015 on gross primary productivity (GPP) at two Norway spruce forest sites representing two contrasting climatic conditions—cold and humid climate at Bílý Kr̆íz̆ (CZ-BK1) vs. moderately warm and dry climate at Rájec (CZ-RAJ). The comparative analyses of GPP was based on a three-year eddy covariance dataset, where 2014 and 2016 represented years with normal conditions, while 2015 was characterized by dry conditions. A significant decline in the forest GPP was found during the dry year of 2015, reaching 14% and 6% at CZ-BK1 and CZ-RAJ, respectively. The reduction in GPP coincided with high ecosystem respiration (Reco) during the dry year period, especially during July and August, when several heat waves hit the region. Additional analyses of GPP decline during the dry year period s...
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We investigated how reduced summer precipitation modifies photosynthetic responses of two model tree species—coniferous Norway spruce and broadleaved sessile oak—to changes in atmospheric CO2 concentration. Saplings were grown under... more
We investigated how reduced summer precipitation modifies photosynthetic responses of two model tree species—coniferous Norway spruce and broadleaved sessile oak—to changes in atmospheric CO2 concentration. Saplings were grown under mountainous conditions for two growing seasons at ambient (400 μmol CO2 mol–1) and elevated (700 μmol CO2 mol–1) CO2 concentration. Half were not exposed to precipitation during the summer (June–August). After two seasons of cultivation under modified conditions, basic photosynthetic characteristics including light-saturated rate of CO2 assimilation (Amax), stomatal conductance (GSmax), and water use efficiency (WUE) were measured under their growth CO2 concentrations together with in vivo carboxylation rate (VC) and electron transport rate (J) derived from CO2-response curves at saturating light. An increase in Amax under elevated CO2 was observed in oak saplings, whereas it remained unchanged or slightly declined in Norway spruce, indicating a down-reg...
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A growing body of scientific evidence indicates that we have entered the Anthropocene Epoch. Many assert that society has exceeded sustainable ecological planetary boundaries and that altered biogeophysical processes are no longer... more
A growing body of scientific evidence indicates that we have entered the Anthropocene Epoch. Many assert that society has exceeded sustainable ecological planetary boundaries and that altered biogeophysical processes are no longer reversible to natural rates of ecosystem functioning. To properly and successfully address societal needs for the future, more holistic and complex methods need to be applied at various spatial and temporal scales. The increasingly interconnected nature of human and natural environments—from individuals to large megacities and entire continents and from cells through ecosystems to the biosphere as a whole (e.g., as seen in the carbon cycle)—demand new and often interdisciplinary and international approaches to address emerging global challenges. With that perspective in mind, the Czech Republic’s National Climate Program was established in 1991 with the aim to understand the impact of global environmental change on society. The National Climate Program was...
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Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature... more
Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature optima of photosynthetic processes will shift towards higher temperatures and the thermostability of the photosynthetic apparatus will increase. The hypothesis was tested for saplings of broadleaved Fagus sylvatica and coniferous Picea abies exposed for 4-5 years to either ambient (AC; 385 µmol mol(-1)) or elevated (EC; 700 µmol mol(-1)) CO2 concentrations. Temperature response curves of photosynthetic processes were determined by gas-exchange and chlorophyll fluorescence techniques. Initial assumptions of reduced light-saturated stomatal conductance and increased leaf temperatures for EC plants were confirmed. Temperature response curves revealed stimulation of light-saturated rates of CO2 assimilation (Amax) and a decline in photorespiration (RL)...
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Carbon assimilation of plants is regarded to be a principal process of the plant's life. Because of the role of carbon dioxide as the nutrient of photosynthesis is possible to consider the process of carbon carboxylation as the direct... more
Carbon assimilation of plants is regarded to be a principal process of the plant's life. Because of the role of carbon dioxide as the nutrient of photosynthesis is possible to consider the process of carbon carboxylation as the direct interconnection between metabolism of plants and global change The results of the experiment with the – long-term fumigation of an experimental N. spruce stand by the doubled (cca 700 ppm) concentration of CO 2 are presented The long-term response of the spruce photosynthetic activity is strongly seasonal-dependent, i.e. the sink strength. The one principal phenomenon was discovered – the manifestation of the photosynthetic acclimation, depression. The level of the photosynthetic rate is decreasing under the long-term effects of elevated CO 2 , i.e. manifestation of the feed-back reaction, comparing the the control-ambient level of CO 2 . The manifestation of photosynthetic acclimation is strongly related to the nutrients status of leaf tissue, the...