23
rd
IUFRO Conference. Air Pollution and Climate Change Effects on Forest Ecosystems. Abstracts
Air Pollution and Climate
Change at Contrasting Altitude
and Latitude
23
rd
IUFRO Conference for Specialists in Air Pollution
and Climate Change Effects on Forest Ecosystems
Murten, Switzerland
September 7–12, 2008
Abstracts
Swiss Federal Institute for Forest,
Snow and Landscape Research
iufro_proceedings_us.qxp:Layout 1 15.8.2008 10:26 Uhr Seite 1 Air Pollution and Climate
Change at Contrasting Altitude
and Latitude

23
rd
IUFRO Conference for Specialists in Air Pollution
and Climate Change Effects on Forest Ecosystems

Murten, Switzerland


Michèle Kaennel Dobbertin
Swiss Federal Research Institute WSL, Birmensdorf, Switzerland

Doris Steiner
Swiss Federal Research Institute WSL, Birmensdorf, Switzerland Scientific Board
Rainer Matyssek
Technical University of Munich TUM, Freising, Germany

Marcus Schaub
Swiss Federal Research Institute WSL, Birmensdorf, Switzerland

Gerhard Wieser
Research and Training Centre for Forests, Natural Hazards and Landscape BFW,
Innsbruck, Austria

Elena Paoletti
Institute of Plant Protection, National Council of Research, Florence, Italy Recommended form of citation
Schaub, M., Kaennel Dobbertin, M., Steiner, D. (Eds) 2008. Air Pollution and Climate
Change at Contrasting Altitude and Latitude. 23rd IUFRO Conference for Specialists in Air
Pollution and Climate Change Effects on Forest Ecosystems. Murten, Switzerland, 7-12
Sept 2008. Abstracts. Birmensdorf, Swiss Federal Research Institute WSL. 162 pp.
by exposure versus dose-related approaches of stress
diagnosis? How realistic are potentials towards process-based,
i.e. mechanistic concepts for risk assessment? In respect to the
above questions the state of the art will be highlighted.

We cordially invite you to this conference and would be
delighted to address the air pollution and climate change
effects on forests which will provide a broad, cause-effect
related basis for environmental policy making.

Marcus Schaub, WSL
Rainer Matyssek, TUM
Gerhard Wieser, BFW
Elena Paoletti, IPP-CNR


Carlo Calfapietra, Silvano Fares, Francesco Loreto
Volatile organic compounds from vegetation and their interaction with ozone
21
Pierre Dizengremel, Yves Jolivet, Didier le Thiec, Marie-Paule Hasenfratz-Sauder, Matthieu
Bagard
Reducing power dependent on metabolic changes as an indicator of effective ozone
phytotoxicity
22
Matthias Dobbertin, Britta Eilmann, Peter Bleuler, Arnaud Giuggiola, Elisabeth Graf Pannatier,
Werner Landolt, Andreas Rigling
Response of mature Scots pines to drought stress: comparing various foliar and stem
wood indicators
23
Raphael Mainiero, Marian Kazda
Fine root dynamics of Fagus sylvatica and the influence of elevated ozone
concentrations
24
Rocío Alonso, Susana Elvira, Victoria Bermejo, Ignacio González-Fernández, Benjamín S.
Gimeno
Relating ozone effects on Mediterranean evegreen forests species with ozone uptake
fluxes: a review of experiments in Spain
25
Carlos Calderón Guerrero, Madeleine S. Günthardt-Goerg, Pierre Vollenweider
Visible and microscopic ozone symptoms in Quercus ilex
26
5
Izabella Franiel, Anna Błocka
Leaf fluctuating asymmetry of Betula pendula Roth as an indicator of environment
quality
27

The effect of elevated CO2 on leaf nitrogen partitioning between photosynthetic and
non-photosynthetic functions in poplar (EuroFACE) during and after CO2 fumigation
35
Suvi Nikula, Pertti Pulkkinen, Sirkku Manninen
Growth and frost hardiness of European and hybrid aspen as influenced by water and
nitrogen
36
Elena Paoletti, Angela J. Nunn, Nancy Grulke, Ursula Metzger, Rainer Matyssek
Ozone amplifies short-term water loss from mature trees by slowing down stomatal
dynamics
37
Martina Pollastrini, Rosanna Desotgiu, Chiara Cascio, Filippo Bussotti, Giacomo A. Gerosa,
Riccardo Marzuoli, Marcus Schaub, Kris Novak, Reto J. Strasser
Populus maximowiczii Henry x P. x berolinensis Dippel: a model tree to study ozone
stress
38
Soo-zin Ryang, Su-young Woo, Sun-mi Je, Seong-han Lee, Hyo-cheng Cheng, Kyeong-nam
Kim, Saeng-gul Baek, Eu-ddeum Lee, Myeong-ja Gwak, Rae-kyoung Han
Ozone effects on physiological, anatomical and morphological changes of several
urban tree species in Seoul
39
6
Ingmar Tulva, Olaf Räim, Eve Eensalu
In situ photosynthesis of three poplar species in EuroFACE
40
Pierre Vollenweider, Andrzej Bytnerowicz, Mark Fenn, Terry Menard, Madeleine S. Günthardt-
Goerg
Structural changes in Ponderosa pine needles exposed to high ozone concentrations
in the San Bernardino Mountains near Los Angeles, CA
41

Yusuf Serengil, Süleyman Özhan
Nutrient and hydrological cycles in forest ecosystems: results of a long-term hydro-
ecological study
49
Adina Călugăr
Effect of fluorine and heavy metals pollution on gamasid mite communities (Acari:
Gamasina) in forest ecosystems in Romania
50
Dongsu Choi, Yoko Watanabe, Tokihisa Agari, Kaichiro Sasa, Hiroto Toda, Takayoshi Koike
The photosynthetic characteristics and nitrogen allocation of black locust (Robinia
pseudoacacia L.) grown in FACE (Free Air CO2 Enrichment) system
51
Elisabeth Graf Pannatier, Peter Blaser, Lorenz Walthert
Importance of bedrock composition for BC/Al ratios in the root zone and
consequences for critical loads of acidity
52
7
Rosa Inclán, Daniel De La Torre, Dolores M. Sánchez, Ana Maria Fernandez, Ángeles Clavero,
Maria del Mar Gonzalez, Ana Cardeña, Ramón Morante, Carla Uribe
Soil-surface CO2 efflux after a fire in a Holm oak, a Scots pine and a Pyrenean oak
forest in Central Spain
53
Ahmet Karakaş, Mustafa Zengin, Mehmet Sarıgül, Faruk Ş. Özay, Kazım Uluer
Assessment of forest damages caused by air pollution (SO2) in the western Black
Sea and Marmara region
54
Václav Lochman, Vít Šrámek, Věra Fadrhonsová, Zora Lachmanová
Long-term acid deposition in the Ore Mountains and its influence on the chemistry of
forest soil
55

Andrzej Bytnerowicz
Need for more integrated collaboration between Europe and North America in
developing and implementing critical loads methodologies
63
Mark Fenn, Edith Allen, Stu Weiss, Fengming Yuan, Thomas Meixner, Benjamin Sanchez
Gimeno
Nitrogen critical loads and management alternatives for N-impacted ecosystems in
California
64
8
Benjamin S. Gimeno, Fengming Yuan, Mark Fenn, Thomas Meixner
Unique characteristics of Mediterranean ecosystems in relation to the determination
of N critical loads
65
Rock Ouimet, Paul A. Arp, Julian Aherne, Shaun Watmough
The critical loads approach: providing the basis for sustainable forest land
management and policies in Canada
66
Lars Lundin
Effects of S, N and HM deposition on natural forest ecosystems
67
Till Spranger
Critical loads of nitrogen: definition and application in European air pollution policy
68
Sarah Jovan, Andrzej Bytnerowicz, Mark Fenn
Effects of elevated nitrogen deposition on lichen communities of mixed conifer forests
in south-eastern Sierra Nevada, California
69
Henning Meesenburg
Critical loads of acidity and nitrogen - application to intensive monitoring plots in

saplings grown under elevated temperature and O3
77
9
Rolf Siegwolf, Maria Rossella Guerrieri,, Matthias Saurer, Maya Jäggi, Paolo Cherubini,
Francesco Ripullone, Marco Borghetti
Different stressors in combination change the initial response of trees to air
pollutants: NO2 and drought effect on tree growth and stable C and O isotopes
78
Pierre Vollenweider, Madeleine S. Günthardt-Goerg
Structural changes triggered by zinc and ozone in plant foliage: comparison of
uptake routes, tissue and cell reactions of two abiotic stress elicitors
79
Ligia Acatrinei, Constantin Ciornei
Physiological aspects in leaves of Quercus petraea under chemical pollution in
Northeastern Romania
80
Masatoshi Aoki, Shino Mizuno, Takahiro Kurohata, Shiro Hatakeyama , Katsutoshi Horie,
Toshiko Fukunaga
Single and combined effects of atmospheric concentration levels of ozone and
peroxides on stomata response
81
Masatoshi Aoki, Merina Azad Shahin, Yun Fan, Takahiro Kurohata, Takeshi Yokoyama, Osamu
Ninagi, Shiro Hatakeyama, Katsutoshi Horie
Single and combined effects of atmospheric concentration levels of ozone and
peroxides on the growth and survival of silkworm
82
Carlos Calderón Guerrero, Madeleine S. Günthardt-Goerg, Pierre Vollenweider
Urban trees and air pollution: Quantitative and qualitative results from Madrid
83
Carlos Correia, Jorge Ferreira Cardoso, Cármen Moreira, Berta Gonçalves, Eunice Bacelar,

birch (Betula pendula)
90
Ivan Seletković, Nenad Potočić, Damir Ugarković, Anamarija Jazbec, Renata Pernar, Ante
Seletković
The influence of climate and relief properties on crown condition status of Fagus
sylvatica: a case study in Medvednica massif, Croatia
91
Anu Sõber, Priit Kupper, Jaak Sõber, Arne Sellin, Krista Lõhmus, Olevi Kull
Free air experiment in deciduous tree canopy with air humidity manipulation (FAHM)
92
Gerhard Wieser, Walter Oberhuber, Andreas Gruber, Michael Bahn
High-elevation forests in a changing environment
93
Vitali Zverev
Impact of pollution and annual climatic fluctuations on growth of mountain birch
94
Elena Zvereva, Mikhail V. Kozlov
Biotic effects of pollution in relation to climate: results of meta-analyses
95
Session 5: Genetic aspects
5
Gail Taylor
Tree genes, air pollution and climate change
96
Maren Olbrich, Elke Gerstner, Günther Bahnweg, Werner Heller, Frank Fleischmann, Wolfgang
Oßwald, Wilma Ritter, Thorsten E. Grams, Maren Schmalmack, Wolfgang zu Castell, Karin
Pritsch, Barbro J. Winkler, Dieter Ernst
Effects of abiotic and biotic stress on gene transcription in European beech (Fagus
sylvatica L.): from saplings to mature trees
97

Apiognomonia errabunda in leaves of adult European beech trees
104
Cristina Vettori, Matthias Fladung, Maren Olbrich, Dieter Ernst, Markussen T., Manfred
Forstreuter, Maik Veste, D. Paffetti, G. Emiliani, Giorgio Citterio, Raffaello Giannini
Gene expression and ecophysiological analyses of different Fagus sylvatica genotypes
under high levels of CO2
105
Session 6: Detection, monitoring and evaluation
6
Werner Eugster
CO2 flux measurements near the alpine treeline at Davos: the need for long-term
research
106
Marco Ferretti, Filippo Bussotti, Marco Calderisi, Gianfranco Fabbio, Bruno Petriccione
Evidence of change in climate, pollution and vegetation in selected forest ecosystems
in Italy over the period 1995-2005
107
Giacomo A. Gerosa, Angelo Finco, Riccardo Marzuoli, Antonio Ballarin Denti
Ozone, water, carbon dioxide and energy fluxes over a Mediterranean macchia in
Italy
108
Mikhail V. Kozlov, Elena Zvereva, Vitali Zverev
Impact of point polluters on terrestrial biota: Comparative analysis
109
Angela J. Nunn, Stan Cieslik, Nancy E. Grulke, Elena Paoletti, Ursula Metzger, Rainer Matyssek
Comparison of ozone fluxes as determined above-canopy, at the canopy and the leaf
level in a mixed beech/spruce stand
110
Remigijus Ozolinčius, Vidas Stakėnas, Rasa Buožytė, Brigita Serafinavičiūtė
Effects of artificial drought on the ground vegetation, crown condition and litterfall in

Seasonal variations of ozone exposure and fluxes in a coastal Holm oak forest
119
Stefan Godzik, Piotr Kubiesa, Włodzimierz Łukasik, Jerzy Szdzuj, Tomasz Staszewski
Response of spruce (Picea abies Karst.) seedlings to different pollution and climatic
conditions in a field experiment
120
Laura González, David Elustondo, Esther Lasheras, Raúl Bermejo, Jesús Miguel Santamaría
Moss biomonitoring of heavy metals and nitrogen in a Pyrenean forest ecosystem
121
Marcel Holy, Sébastien Leblond, Roland Pesch, Winfried Schröder
Spatiotemporal patterns of metal and nitrogen accumulation in French mosses
122
Lukas Kleppin, Roland Pesch, Winfried Schröder
Implementation of the WebGIS MossMet for the UNECE Moss Monitoring
123
Eugenija Kupcinskiene, Satu Huttunen
Factors influencing ammonia pollution effects on Scots pine stands
124
Eugenija Kupcinskiene, Alfredas Radzevicius, Ricardas Taraskevicius, Vitas Marozas, Aida
Stikliene, Asta Judzentiene, Sabina Mikulioniene, Almantas Kliucius, Edmundas Bartkevičius,
Dalia Jasineviciene, Isabelle Schwob, Jacques Rabier, Rimante Zinkute
Present cement dust pollution still effects Scots pine (Pinus sylvestris L.)
125
Niina M. Lappalainen, Satu Huttunen, Kaisa Lakkala, Hanne Suokanerva
Acclimation of an endohydric moss Polytrichum juniperinum Hedw. to light and
ultraviolet radiation
126
Leona Matoušková, Iva Hůnová
Surface ozone concentrations and visible leaf injury of selected species in the
Jizerske hory Mts, the Czech Republic

pollution along traffic routes through the Swiss Alps
134
Session 7: Risk assessment and modeling
7
Peter E. Thornton, Scott C. Doney, Keith Lindsay, J. Keith Moore, Natalie Mahowald, James T.
Randerson, Inez Fung, Jean-François Lamarque, Johannes J. Feddema, Yen-Huei Lee
Fundamental influence of carbon-nitrogen cycle coupling on climate-carbon cycle
feedbacks
135
Aleksander Astel, Stanisław Małek
Multiple modeling in water chemistry flows assessment in a mountain spruce
catchment
136
Marek Fabrika, Katarína Střelcová, Ľubica Ditmarová
Tree growth simulator as a tool for tree transpiration modeling depending on climatic
parameters
137
Johan Uddling, Ronald M. Teclaw, Kurt S. Pregitzer, Davis S. Ellsworth
Stomatal ozone uptake of forest trees under rising atmospheric [CO2] and
tropospheric [O3]
138
Colin Whitfield, Shaun Watmough, Julian Aherne, Marjorie McDonald
Assessing the risk of acidification from industrial activities in the Athabasca Oil Sands
Region of Alberta
139
Salim Belyazid, Harald Sverdrup, Sabine Braun, Dani Kurz
Forest ecosystem responses to nitrogen loads under a changing climate: results from
integrated dynamic modelling of forest ecosystems in Switzerland and Sweden
140
Alessandra De Marco, Ilaria D’Elia, Mariantonia Bencardino, Augusto Screpanti, Giovanni

injuries in young forest trees
147
Markus Meili, Ishi Buffam, Peder Blomkvist, Hjalmar Laudon, Kevin Bishop
Climatic influences on the coupling of water fluxes, organic carbon fluxes and
mercury fluxes from boreal forest soils
148
Roland Pesch, Gunther Schmidt, Winfried Schröder
Mapping the carbon sequestration in forests of North Rhine-Westphalia - applying
regression kriging
149
Gerhard Soja, Werner Hann, Stephan Pietsch
Medium-term trends in meteorological conditions, ozone exposure and ozone uptake
of oak trees in eastern Austria: a trend analysis 1990–2007
150
Makoto Watanabe, Naoki Matsuo, Masahiro Yamaguchi, Hideyuki Matsumura, Yoshihisa Kohno,
Takeshi Izuta
Risk assessment of ozone for carbon absorption of representative Japanese conifers
151
Author index
153
Keyword index
157
15
16
Martin Beniston
While changes in the long-term mean state of climate will have many important consequences
on numerous environmental, social, and economic sectors, the most significant impacts of
climatic change are likely to arise from shifts in the intensity and frequency of extreme weather
events. Indeed, insurance costs resulting from extreme weather events have been steadily
increasing over the last two decades, in response to both population pressures in regions that

ever. Still, knowledge about O3 effects on trees is dominated by the outcome of experimental
studies with juvenile individuals under growth conditions of limited ecological significance.
Available information of this kind mostly shows distinct O3 sensitivity, although evidence is
inconsistent across tree species and genotypes as well as successional status (pioneer vs.
climax) or growth habit (evergreenness vs. deciduousness). New perspectives towards
ecologically meaningful clarification have been opened, through advances in free-air fumigation
methodology, allowing controlled experimentation with enhanced O3 regimes, also in
combination with elevated CO2, on mature trees in plantations and forests. Two prominent
studies of this latter kind were Aspen FACE (Rhinelander, USA) and CASIROZ/SFB 607
(Freising, Germany), key findings of which will be cross-compared and examined for
consistencies.
Tendencies emerge of ameliorating effects of elevated CO2 on O3 impact, or inversely, of the
potential of O3 in mitigating C sink strength under high CO2 supply. Evidently, tree
responsiveness is largely biased through the kind of competition and interactions with parasites
and drought. Pioneer tree species appear to be more sensitive to O3 than climax species,
becoming evident within Aspen FACE (Populus tremuloides/Betula papyrifera vs. Acer
saccharum) compared to CASIROZ/SFB 607 (Fagus sylvatica vs. Picea abies). Comparisons will
be extended towards experimental findings on O3 responsiveness from the harsh timberline
ecotone of the European Alps, exemplifying Larix decidua (deciduous pioneer) vs. Pinus
cembra (evergreen climax species). In demonstrating such comparisons, the need for basing
O3 risk assessment on mechanistic grounds will become evident, the latter being defined
through the biophysics of O3 uptake (i.e., actual O3 dose) and the metabolic sensitivity
expressed on an O3 uptake basis (i.e., effective dose). Novel experimental concepts for
achieving this task will be addressed, enabling for tree-stand process scaling and new modeling
tools for O3 risk assessment. On the grounds of methodological advances and recent evidence
gained, a research concept will be outlined that should succeed Aspen FACE and CASIROZ/SFB
607 to complete the elaboration of mechanistically founded O3 risk assessment tools for forest
trees and stands in view of the demanding requirements of "climate change" scenarios.
(1) Ecophysiology of Plants, Technische Universität München, Freising, Germany
(2) School of Forest Resources and Environmental Science, Michigan Technological University, Houghton,

A
is fully oxidised) to F
P
(where F
P
= F
M
under saturating excitation light) had a polyphasic
behavior. The analysis of the transient is called the JIP-test.
Ambient ozone concentrations lead to the closure of reaction centres (RC), which function as
dissipater centers. All the parameters connected to dissipation were also increased. The
quantum yield efficiency (F
V
/F
M
) demonstrated only little sensitivity. The response was not
proportional to ozone exposition and/or fluxes. During the first part of the season, leaves were
very resilient and photosynthesis could be transiently stimulated by ozone. Only towards the
end of the growing season, efficiency and performance parameters showed a sudden drop. For
species with terminated growth during the first part of the season, ozone has little effect on
carbon fixation and storage. Growth was significantly reduced in species with a continuous
growth pattern. The comparison of the shape of FT normalized per F
0
and F
M
and per F
0
and F
J
shows evident peaks at the steps K, J and I. Each peak corresponds to specific biochemical

phytotronic chambers with different levels of ozone. In all cases, we showed a coordinated
increase of several enzymes involved in phenolic synthesis and particularly in lignin synthesis
in response to ozone treatment in leaves. The stimulation of enzyme activities was generally
associated with a higher Klason lignin content in extract-free leaves. In addition, stress lignins
synthesized in response to ozone displayed a distinct structure, relative to constitutive lignins.
The highest changes in lignification and in enzyme activities were obtained with the highest
ozone dose. All these results suggested a possible role of lignin in tolerance to ozone by
limiting the necrosis extension.
Ozone combined with elevated carbon dioxide resulted in similar observations. Nevertheless,
the stimulation of lignin biosynthesis was less marked than with ozone alone. High carbon
dioxide could lower the detrimental effect of ozone in leaves.
In stems, ozone reduced lignin biosynthesis probably due to lower availability in carbon
skeletons. The modifications in cell-wall component synthesis were related to anatomical
modifications and some wood properties.
(1) UMR1137 INRA-Nancy Université, Ecologie et Ecophysiologie Forestières, Nancy, France
(2) UMR 206 AgroParisTech-INRA, AgroParisTech, Centre de Grignon, France
(3) LERMAB, ENGREF, Nancy, France
Effects of ozone and elevated carbon dioxide on lignification in leaves
and stems
In: Schaub, M., Kaennel Dobbertin, M., Steiner, D. (Eds) 2008. Air Pollution and Climate Change at Contrasting Altitude
and Latitude. 23rd IUFRO Conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems.
Murten, Switzerland, 7-12 Sept 2008. Abstracts. Birmensdorf, Swiss Federal Research Institute WSL. 162 pp.
Session 1: Mechanisms of action and indicator development
Corresponding author: Mireille Cabané ()
20
Carlo Calfapietra, Silvano Fares, Francesco Loreto
Volatile Organic Compounds (VOCs) emitted from vegetation (particularly isoprenoids)
represent an important source of the atmospheric hydrocarbons (Guenther et al., 1991).
Biogenic VOC emissions almost double the anthropogenic source. When biogenic VOCs mix
with NOx in the presence of UV radiation, ozone is being formed. Biogenic contribution to

ozone
In: Schaub, M., Kaennel Dobbertin, M., Steiner, D. (Eds) 2008. Air Pollution and Climate Change at Contrasting Altitude
and Latitude. 23rd IUFRO Conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems.
Murten, Switzerland, 7-12 Sept 2008. Abstracts. Birmensdorf, Swiss Federal Research Institute WSL. 162 pp.
Session 1: Mechanisms of action and indicator development
Corresponding author: Carlo Calfapietra ()
21
Pierre Dizengremel (1), Yves Jolivet (1), Didier le Thiec (2), Marie-Paule Hasenfratz-Sauder
(1), Matthieu Bagard (1)
Long-term exposures of higher plants to low ozone concentrations affect biochemical processes
prior to any detectable symptoms of visible injury. On the other hand, the current critical level
of ozone used to determine the threshold for damaging plants (biomass loss) is still based on
the seasonal sum of the external concentrations of the pollutant above 40 nL.L
-1
(AOT40). A
more relevant concept developed a flux-based approach taking into account the actual ozone
flux in the leaf through the stomata (cumulative uptake of ozone=CUO). CUO however ignores
the internal capacity of leaf defense, which led to the concept of "effective ozone flux", a
balance between stomatal flux and the intensity of cellular detoxification (Musselman et al.,
2006; Paoletti and Manning, 2007; Wieser and Matyssek, 2007).
Although the direct detoxification of ozone (and ROS) can primarily be carried out by cell wall
ascorbate, the existing level of ascorbate is not sufficient as a good indicator for the degree of
cell sensitivity (D’Haese et al., 2005). A regeneration of the antioxidant barrier is needed,
implying an increased production of reducing power (NAD(P)H). It is made possible through
the increased participation of the catabolic pathways. In addition, the large change in the
rubisco/PEPcase ratio, due to a huge increase in activity of the latter enzyme, leads to changes
in carbon isotopic discrimination which could, in turn, modify water use efficiency. The
challenge is to adjust these indicators in a leaf-model system (Dizengremel et al., 2008).
References:
D’Haese, D., Vandermeiren, K., Asard, H., Horemans, N., 2005. Other factors than apoplastic

m altitude with annual precipitation of 600 mm. The four irrigated and four control plots were
randomly assigned. They are 0.1 ha in size with 75 trees on average. The irrigation, which is
carried out at night during the monthsof April to October, roughly doubled the mean annual
precipitation. Various tree crown parameters were annually assessed on all trees, including
relative foliage amount in 5%-steps and mortality. In 2004, 13 dominant trees were selected,
7 from the irrigated and 6 from the control plots covering the whole range of foliage classes.
Their inter-annual growth was assessed weekly using the pinning method. These trees were
harvested in April 2006 and analyzed for tree ring width, stable carbon isotope ratios, shoot
and needle length, fresh and dry weight and projected needle area.
Irrigation had a significant effect on all of the parameters. But tree foliage class also correlated
significantly with most parameters showing the influence of the sample tree selection. Mean
needle length, fresh and dry needle weight, shoot length and ring width all correlated positively
with estimated foliage amount. Specific leaf area and dry/fresh needle weight were negatively
correlated. Water use efficiency, as estimated from stable carbon isotope ratios, correlated
highly with a calculated drought index and was higher for trees with lower foliage amount.
Trees with more foliage began stem growth earlier and ended later than trees with low foliage.
Irrigation increased foliage amount between 2003 and 2007 by roughly 6%, while trees in
control plots showed a loss of 10% foliage, probably due to the dry years 2003-2005. Mortality
was 6.1% on the control plots as compared to 2.5% on the irrigated plots. Irrigation increased
needle length by up to 70%, shoot length up to 100%, ring width up to 150% of the control
trees. Ring width and water use efficiency reacted already in the first year of irrigation, shoot
and needle length with a one-year delay. Irrigated trees showed longer stem growth and a
delayed earlywood/latewood transition than control trees. Their water-use efficiency decreased
significantly, even for trees for lower foliage amount.
Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
Response of mature Scots pines to drought stress: comparing various
foliar and stem wood indicators
In: Schaub, M., Kaennel Dobbertin, M., Steiner, D. (Eds) 2008. Air Pollution and Climate Change at Contrasting Altitude
and Latitude. 23rd IUFRO Conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems.
Murten, Switzerland, 7-12 Sept 2008. Abstracts. Birmensdorf, Swiss Federal Research Institute WSL. 162 pp.

Mainiero, R., Kazda, M., 2006. Depth-related fine root dynamics of Fagus sylvatica during
exceptional drought. Forest Ecology and Management 237, 135-142.
(1) Institute For Applied Plant Biology IAP, Schönenbuch, Switzerland
(2) Ulm University, Ulm, Germany
Fine root dynamics of Fagus sylvatica and the influence of elevated ozone
concentrations
In: Schaub, M., Kaennel Dobbertin, M., Steiner, D. (Eds) 2008. Air Pollution and Climate Change at Contrasting Altitude
and Latitude. 23rd IUFRO Conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems.
Murten, Switzerland, 7-12 Sept 2008. Abstracts. Birmensdorf, Swiss Federal Research Institute WSL. 162 pp.
Session 1: Mechanisms of action and indicator development
Corresponding author: Raphael Mainiero ()
24