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Pluies acides, production de nitrate dans les sols forestiers et annees de secheresse estivale: cofacteurs de risque de deperissement des forets. Reflexions sur la synergie.
1989
Bardy J.A.
Deperissement des forets et pollution atmospherique [pluies acides, degats par region et par essence].
1987
Muller M. | Wunenburger R.
Possible causes of the recent rapid increase in the radial increment of silver fir in the Western Carpathians
2014
Bošeľa, Michal | Petráš, Rudolf | Sitková, Zuzana | Priwitzer, Tibor | Pajtík, Jozef | Hlavatá, Helena | Sedmák, Róbert | Tobin, Brian
Silver fir is one of the most productive and ecologically valuable native European tree species, however, it has been experiencing decline which has periodically occurred over its natural range. This paper aims to investigate the recent climate–growth relationships of silver fir (Abies alba Mill.) and its temporal change along the course of its life. Long-term tree-ring databases, as well as records on climate, atmospheric SO2, NO3 and acid concentrations from four different regions in the Western Carpathians were used. The results provide clear evidence of significant increase of silver fir's radial increment over the entire Western Carpathian area since 1970–1980. The results indicated that the most probable factors behind the rapid recovery of tree radial increment were reductions in emissions of NO3 and SO2, alongside a significant increase in mean June, July and April temperatures.
Afficher plus [+] Moins [-]Within season and carry-over effects following exposure of grassland species mixtures to increasing background ozone
2011
Hayes, Felicity | Mills, Gina | Harmens, Harry | Wyness, Kirsten
Few studies have investigated effects of increased background ozone in the absence of episodic peaks, despite a predicted increase throughout the northern hemisphere over the coming decades. In this study Leontodon hispidus was grown with Anthoxanthum odoratum or Dactylis glomerata and exposed in the UK to one of eight background ozone concentrations for 20 weeks in solardomes. Seasonal mean ozone concentrations ranged from 21.4 to 102.5 ppb. Ozone-induced senescence of L. hispidus was enhanced when grown with the more open canopy of A. odoratum compared to the denser growing D. glomerata. There was increased cover with increasing ozone exposure for both A. odoratum and D. glomerata, which resulted in an increase in the grass:Leontodon cover ratio in both community types. Carry-over effects of the ozone exposure were observed, including delayed winter die-back of L. hispidus and acceleration in the progression from flowers to seed-heads in the year following ozone exposure.
Afficher plus [+] Moins [-]Anthropogenic nitrogen deposition alters growth responses of European beech (Fagus sylvativa L.) to climate change
2018
Hess, Carsten | Niemeyer, Thomas | Fichtner, Andreas | Jansen, Kirstin | Kunz, Matthias | Maneke, Moritz | von Wehrden, Henrik | Quante, Markus | Walmsley, David | von Oheimb, Goddert | Härdtle, Werner
Global change affects the functioning of forest ecosystems and the services they provide, but little is known about the interactive effects of co-occurring global change drivers on important functions such as tree growth and vitality. In the present study we quantified the interactive (i.e. synergistic or antagonistic) effects of atmospheric nitrogen (N) deposition and climatic variables (temperature, precipitation) on tree growth (in terms of tree-ring width, TRW), taking forest ecosystems with European beech (Fagus sylvatica L.) as an example. We hypothesised that (i) N deposition and climatic variables can evoke non-additive responses of the radial increment of beech trees, and (ii) N loads have the potential to strengthen the trees' sensitivity to climate change. In young stands, we found a synergistic positive effect of N deposition and annual mean temperature on TRW, possibly linked to the alleviation of an N shortage in young stands. In mature stands, however, high N deposition significantly increased the trees’ sensitivity to increasing annual mean temperatures (antagonistic effect on TRW), possibly due to increased fine root dieback, decreasing mycorrhizal colonization or shifts in biomass allocation patterns (aboveground vs. belowground). Accordingly, N deposition and climatic variables caused both synergistic and antagonistic effects on the radial increment of beech trees, depending on tree age and stand characteristics. Hence, the nature of interactions could mediate the long-term effects of global change drivers (including N deposition) on forest carbon sequestration. In conclusion, our findings illustrate that interaction processes between climatic variables and N deposition are complex and have the potential to impair growth and performance of European beech. This in turn emphasises the importance of multiple-factor studies to foster an integrated understanding and models aiming at improved projections of tree growth responses to co-occurring drivers of global change.
Afficher plus [+] Moins [-]Behaviour of arsenic in forested catchments following a high-pollution period
2011
Novák, Martin | Erbanova, Lucie | Fottova, Daniela | Cudlin, P. (Pavel) | Kubena, Ales
Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north–south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007–2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha⁻¹ yr⁻¹). In contrast, the preceding period (1995–2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil.
Afficher plus [+] Moins [-][Forest decline in Federal Republic of Germany [photooxidants, ozone, soil nutrients, "new damage"]]
1987
Prinz, B. (Landesanstalt fuer Immissionsschutz des Landes Nordrhein-Westfalen, Essen (Germany, F.R.)) | Krause, G.H.M.
Well-intentioned, but poorly implemented: Debris from coastal bamboo fences triggered mangrove decline in Thailand
2019
Pranchai, Aor | Jenke, Michael | Berger, Uta
Along the Upper Gulf of Thailand, coastal fences and breakwaters have been constructed using bamboo since 2005. Despite their potential benefits, bamboo structures disintegrate within seven years releasing floating debris which severely damages mangrove tree stems. The aim of the study was to investigate whether such stem damage resulted in the decline of Avicennia spp. stands along the Upper Gulf of Thailand. Tree health assessments were conducted to assess the probability of crown dieback in damaged and undamaged trees. Satellite-derived time-series of vegetation indices were used to detect long-term forest decline. In contrast to the unaffected landward mangroves, seaward mangroves were unable to recover from insect-induced defoliation events after the collapse of a nearby fence. Furthermore, there was a significantly higher probability that damaged trees showed signs of moderate-to-severe crown dieback. It is recommended that bamboo fences be secured by replacing individual stems before they become detached.
Afficher plus [+] Moins [-]Chernoff-Flury faces: a statistical means for representing multivariate response parameters of air pollution induced injury on plants
1989
Schwela, D.H. | Krause, G.H.M. (Landesanstalt fur Immissionsschutz des Landes NW, Wallneyerstrasse 6, 4300 Essen 1 (Germany, F.R.))
[Forest decline and atmospheric pollution [acid rain, damage by region and by species]]
1987
Muller, M. (Ministere de l'Environnement, Neuilly-sur-Seine (France). Service de Recherche des Etudes et du Traitement sur l'Environnement) | Wunenburger, R.