scholarly journals Assessing the Contrasting Effects of the Exceptional 2015 Drought on the Carbon Dynamics in Two Norway Spruce Forest Ecosystems

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 988
Author(s):  
Caleb Mensah ◽  
Ladislav Šigut ◽  
Milan Fischer ◽  
Lenka Foltýnová ◽  
Georg Jocher ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Large Scale ◽  
Forest Ecosystems ◽  
Heat Waves ◽  
Ecosystem Respiration ◽  
Vapour Pressure Deficit ◽  
Climate Projections ◽  
Summer Drought ◽  
Spruce Forest ◽  
Norway Spruce Forest

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 suggested that a vapour pressure deficit played a more important role than the soil volumetric water content at both investigated sites, highlighting the often neglected importance of considering the species hydraulic strategy (isohydric vs. anisohydric) in drought impact assessments. The study indicates the high vulnerability of the Norway spruce forest to drought stress, especially at sites with precipitation equal or smaller than the atmospheric evaporative demand. Since central Europe is currently experiencing large-scale dieback of Norway spruce forests in lowlands and uplands (such as for CZ-RAJ conditions), the findings of this study may help to quantitatively assess the fate of these widespread cultures under future climate projections, and may help to delimitate the areas of their sustainable production.

scholarly journals The impact of drought on total ozone flux in a mountain Norway spruce forest

2020 ◽  
Vol 66 (No. 7) ◽  
pp. 280-278 ◽  
Author(s):  
Thomas Agyei ◽  
Stanislav Juráň ◽  
Kojo Kwakye Ofori-Amanfo ◽  
Ladislav Šigut ◽  
Otmar Urban ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Stomatal Closure ◽  
Severe Drought ◽  
Summer Drought ◽  
Spruce Forest ◽  
Soil Humidity ◽  
Drought Period ◽  
The Impact ◽  
Mild Drought ◽  
Norway Spruce Forest

In order to understand the impact of summer drought on dry deposition of tropospheric ozone (O<sub>3</sub>), we compared severe and mild drought periods of summer 2018 in a mountain Norway spruce forest at Bílý Kříž, Beskydy Mts. An eddy covariance technique was applied to measure diurnal courses of the ecosystem O<sub>3</sub> and CO<sub>2</sub> fluxes. Low O<sub>3</sub> deposition was recorded in the morning and evening, while the highest CO<sub>2</sub> and O<sub><sup>3</sup></sub> fluxes were recorded during the central hours of the day. Total O<sub>3</sub> deposition during severe drought (soil humidity 13%) was significantly higher than the deposition during the mild drought period (soil humidity 19%). Our data indicate that high vapour pressure deficit and low soil humidity during severe drought led to the stomatal closure, while non-stomatal O<sub>3</sub> deposition, associated with chemical reactions of O<sub>3</sub> with NO and volatile organic compounds, are responsible for higher total O<sub>3</sub> deposition during the severe drought period. Therefore, we assume that under severe drought stomatal O<sub>3</sub> uptake decreases but non-stomatal depositions to forest ecosystems substantially increase.

scholarly journals Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Alexander Ač ◽  
Zbyněk Malenovský ◽  
Otmar Urban ◽  
Jan Hanuš ◽  
Martina Zitová ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Norway Spruce ◽  
Forest Ecosystems ◽  
Gross Primary Production ◽  
Imaging Spectroscopy ◽  
Fluorescence Emission ◽  
Net Ecosystem Exchange ◽  
Spruce Forest ◽  
Temporal Dimension ◽  
Norway Spruce Forest

We explored ability of reflectance vegetation indexes (VIs) related to chlorophyll fluorescence emission (, ) and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as ) to track changes in the CO2assimilation rate and Light Use Efficiency (LUE) in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO2assimilation () was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ() of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to (). In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP), Net Ecosystem Exchange (NEE), and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index with NEE and GPP.

The contribution of hydroxylamine content to spatial variability of N2O formation in soil of a Norway spruce forest

2016 ◽  
Vol 178 ◽  
pp. 76-86 ◽  
Author(s):  
Shurong Liu ◽  
Michael Herbst ◽  
Roland Bol ◽  
Nina Gottselig ◽  
Thomas Pütz ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Norway Spruce ◽  
Spruce Forest ◽  
N2o Formation ◽  
Norway Spruce Forest

scholarly journals Upside-down fluxes Down Under: CO<sub>2</sub> net sink in winter and net source in summer in a temperate evergreen broadleaf forest

2018 ◽  
Vol 15 (12) ◽  
pp. 3703-3716 ◽  
Author(s):  
Alexandre A. Renchon ◽  
Anne Griebel ◽  
Daniel Metzen ◽  
Christopher A. Williams ◽  
Belinda Medlyn ◽  
...  
Keyword(s):  
Large Scale ◽  
Vegetation Index ◽  
Ecosystem Respiration ◽  
Vapour Pressure Deficit ◽  
Summer Rainfall ◽  
Mean Annual Precipitation ◽  
Surface Conductance ◽  
Mean Annual Temperature ◽  
Eddy Covariance Method ◽  
Area Index

Abstract. Predicting the seasonal dynamics of ecosystem carbon fluxes is challenging in broadleaved evergreen forests because of their moderate climates and subtle changes in canopy phenology. We assessed the climatic and biotic drivers of the seasonality of net ecosystem–atmosphere CO2 exchange (NEE) of a eucalyptus-dominated forest near Sydney, Australia, using the eddy covariance method. The climate is characterised by a mean annual precipitation of 800 mm and a mean annual temperature of 18 ∘C, hot summers and mild winters, with highly variable precipitation. In the 4-year study, the ecosystem was a sink each year (−225 g C m−2 yr−1 on average, with a standard deviation of 108 g C m−2 yr−1); inter-annual variations were not related to meteorological conditions. Daily net C uptake was always detected during the cooler, drier winter months (June through August), while net C loss occurred during the warmer, wetter summer months (December through February). Gross primary productivity (GPP) seasonality was low, despite longer days with higher light intensity in summer, because vapour pressure deficit (D) and air temperature (Ta) restricted surface conductance during summer while winter temperatures were still high enough to support photosynthesis. Maximum GPP during ideal environmental conditions was significantly correlated with remotely sensed enhanced vegetation index (EVI; r2 = 0.46) and with canopy leaf area index (LAI; r2 = 0.29), which increased rapidly after mid-summer rainfall events. Ecosystem respiration (ER) was highest during summer in wet soils and lowest during winter months. ER had larger seasonal amplitude compared to GPP, and therefore drove the seasonal variation of NEE. Because summer carbon uptake may become increasingly limited by atmospheric demand and high temperature, and because ecosystem respiration could be enhanced by rising temperatures, our results suggest the potential for large-scale seasonal shifts in NEE in sclerophyll vegetation under climate change.

scholarly journals Former agriculture impacts on properties of Norway spruce forest

2011 ◽  
Vol 20 (3) ◽  
pp. 437 ◽  
Author(s):  
D. Kacalek ◽  
D. Dusek ◽  
J. Novak ◽  
M. Slodicak ◽  
J. Bartos ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Spruce Forest ◽  
Norway Spruce Forest
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