scholarly journals Energy dissipation in drought-avoiding and drought-tolerant tree species at midday during the Mediterranean summer

2000 ◽  
Vol 20 (2) ◽  
pp. 131-138 ◽  
Author(s):  
E. Martinez-Ferri ◽  
L. Balaguer ◽  
F. Valladares ◽  
J. M. Chico ◽  
E. Manrique
Keyword(s):  
Energy Dissipation ◽  
Tree Species ◽  
Drought Tolerant ◽  
The Mediterranean

scholarly journals Drought-influenced mortality of tree species with different predawn leaf water dynamics in a decade-long study of a central US forest

2015 ◽  
Vol 12 (10) ◽  
pp. 2831-2845 ◽  
Author(s):  
L. Gu ◽  
S. G. Pallardy ◽  
K. P. Hosman ◽  
Y. Sun
Keyword(s):  
Water Potential ◽  
Tree Species ◽  
Tree Mortality ◽  
Leaf Water ◽  
Water Dynamics ◽  
Annual Variations ◽  
Rooting Zone ◽  
Risk Of Death ◽  
Drought Tolerant ◽  
Precipitation Regimes

Abstract. Using decade-long continuous observations of tree mortality and predawn leaf water potential (ψpd) at the Missouri Ozark AmeriFlux (MOFLUX) site, we studied how the mortality of important tree species varied and how such variations may be predicted. Water stress determined inter-annual variations in tree mortality with a time delay of 1 year or more, which was correlated fairly tightly with a number of quantitative predictors formulated based on ψpd and precipitation regimes. Predictors based on temperature and vapor pressure deficit anomalies worked reasonably well, particularly for moderate droughts. The exceptional drought of the year 2012 drastically increased the mortality of all species, including drought-tolerant oaks, in the subsequent year. The drought-influenced tree mortality was related to the species position along the spectrum of ψpd regulation capacity with those in either ends of the spectrum being associated with elevated risk of death. Regardless of species and drought intensity, the ψpd of all species recovered rapidly after sufficiently intense rain events in all droughts. This result, together with a lack of immediate leaf and branch desiccation, suggests an absence of catastrophic hydraulic disconnection in the xylem and that tree death was caused by significant but indirect effects. Species differences in the capacity of regulating ψpd and its temporal integral were magnified under moderate drought intensities but diminished towards wet and dry extremes. Severe droughts may overwhelm the capacity of even drought-tolerant species to maintain differential levels of water potential as the soil becomes exhausted of available water in the rooting zone, thus rendering them more susceptible to death if predisposed by other factors such as age.

scholarly journals Floristic Change at the Drought Limit of European Beech (Fagus sylvatica L.) to Downy Oak (Quercus pubescens) Forest in the Temperate Climate of Central Europe

2017 ◽  
Vol 45 (2) ◽  
pp. 646-654 ◽  
Author(s):  
Albert REIF ◽  
Fotios XYSTRAKIS ◽  
Stefanie GÄRTNER ◽  
Uwe SAYER
Keyword(s):  
Fagus Sylvatica ◽  
Tree Species ◽  
European Beech ◽  
Temperate Climate ◽  
Soil Conditions ◽  
Quercus Pubescens ◽  
Drought Tolerant ◽  
Tolerant Species ◽  
Fagus Sylvatica L ◽  
Shallow Soils

An increase in drought could cause shifts in species composition and vegetation structure. In forests it limits the occurrence of drought sensitive tree species which become replaced by drought tolerant tree species and forest communities. Under temperate macroclimatic conditions, European beech (Fagus sylvatica L.) naturally dominates the forested landscape, except on extremely shallow soil in combination with high irradiation. On these sites beech reaches its drought limit, and is replaced by forests dominated by species like downy Oak (Quercus pubescens s.l.) and English Oak (Quercus petraea L). Phytosociological and ecological data were collected in the transition (ecotone) between European beach stands and stands of more drought tolerant species in order to quantify the drought intensity threshold, above which beech is replaced by drought tolerant species. It was shown that favourable topographic and soil conditions partially compensated the unsuitable climatic conditions for beech. The ecotone between these forest types was found to be characterized by shallow soils with an available soil water storage capacity of 73 l/m² or less, and an irradiation intensity of 6000 MJ/m2 or more during the growing season. This indicates that under conditions of climate change beech would naturally still remain the dominant tree species on the majority of central European forest sites.

scholarly journals Characterization of turbulence and validation of fine-scale parametrization in the Mediterranean Sea during BOUM experiment

2011 ◽  
Vol 8 (5) ◽  
pp. 8961-8998 ◽  
Author(s):  
Y. Cuypers ◽  
P. Bouruet-Aubertot ◽  
C. Marec ◽  
J.-L. Fuda
Keyword(s):  
Energy Dissipation ◽  
Mediterranean Sea ◽  
Fine Scale ◽  
Data Set ◽  
Mean Values ◽  
The Mediterranean ◽  
Microstructure Measurements ◽  
High Level ◽  
Anticyclonic Eddies

Abstract. One main purpose of BOUM experiment was to give evidence of the possible impact of submesoscale dynamics on biogeochemical cycles. To this aim physical as well as biogeochemical data were collected along a zonal transect through the western and eastern basins. Along this transect 3 day fixed point stations were performed within anticyclonic eddies during which microstructure measurements were collected over the first 100 m. We focus here on the characterization of turbulent mixing induced by internal wave breaking. The analysis of microstructure measurements revealed a high level of turbulence in the seasonal pycnocline and a moderate level below with energy dissipation mean values of the order of 10−6 W kg−1 and 10−8 W kg−1, respectively. Fine-scale parameterizations developed to mimic energy dissipation produced by internal wavebreaking were then tested against these direct measurements. Once validated a parameterization has been applied to infer energy dissipation and mixing over the whole data set, thus providing an overview over a latitudinal section of the Mediterranean sea. The results evidence a significant increase of dissipation at the top and base of eddies associated with strong near inertial waves. Vertical turbulent diffusivity is increased both in these regions and in the weakly stratified eddy core.

scholarly journals Eriobotrya japonica (loquat).

2020 ◽  
Author(s):  
Julissa Rojas-Sandoval
Keyword(s):  
South Africa ◽  
New Zealand ◽  
Trinidad And Tobago ◽  
Tree Species ◽  
Mediterranean Region ◽  
Eriobotrya Japonica ◽  
Native Vegetation ◽  
Galápagos Islands ◽  
Ornamental Tree ◽  
The Mediterranean

Abstract Eriobotrya japonica is a perennial tree species that has been widely grown as an ornamental tree and for its sweet, edible fruits. Mammals and birds feed on the fruit and disseminate the seeds into the wild, facilitating the establishment of new plants in areas outside cultivation. Once established, this species has the potential to form tall stands that replace native vegetation. Currently it is listed as invasive in the Mediterranean region, Australia, New Zealand, Réunion, Hawaii, Chile, Galapagos Islands, Trinidad and Tobago and South Africa.

scholarly journals The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric co-dominants

2021 ◽  
Author(s):  
Michael Benson ◽  
Chelcy Miniat ◽  
Andrew Oishi ◽  
Sander Denham ◽  
Jean-Christophe Domec ◽  
...  
Keyword(s):  
Tree Species ◽  
Acer Saccharum ◽  
The Other ◽  
Stand Age ◽  
Carbon Uptake ◽  
Quercus Alba ◽  
Forest Species ◽  
Xylem Embolism ◽  
Drought Tolerant ◽  
Xylem Vulnerability

The coordination of plant leaf water potential (Ψ) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. There is a general consensus that trees with vulnerable xylem regulate Ψ more conservatively than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh., and Liriodendron tulipifera L., by synthesizing 1600 Ψ observations, 122 xylem embolism curves, and xylem anatomical measurements across ten forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated Ψ less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose Ψ regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought-prone future. We end by discussing mechanisms that allow these species to tolerate and/or recover from hydraulic damage.

A tree species range in the face of climate change: cork oak as a study case for the Mediterranean biome

2017 ◽  
Vol 136 (3) ◽  
pp. 555-569 ◽  
Author(s):  
Federico Vessella ◽  
Javier López-Tirado ◽  
Marco Cosimo Simeone ◽  
Bartolomeo Schirone ◽  
Pablo J. Hidalgo
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Cork Oak ◽  
Species Range ◽  
The Face ◽  
Study Case ◽  
The Mediterranean

scholarly journals Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants

2013 ◽  
Vol 10 (9) ◽  
pp. 5855-5873 ◽  
Author(s):  
A. Bracho-Nunez ◽  
N. M. Knothe, ◽  
S. Welter ◽  
M. Staudt ◽  
W. R. Costa ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Plant Species ◽  
Tree Species ◽  
Mediterranean Species ◽  
Voc Emission ◽  
Mediterranean Plants ◽  
Volatile Organic ◽  
Leaf Level ◽  
The Mediterranean

Abstract. Emission inventories defining regional and global biogenic volatile organic compounds (VOC) emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects). The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene < limonene < sabinene < ß-pinene). Mediterranean plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed heterogeneous emissions, including reactive VOC species which are not easily detected by flux measurements, give reason to perform more screening at leaf level and, whenever possible, within the forests under ambient conditions.

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