Abstract
Databases are needed for the ozone (O3 ) risk assessment on adult forest trees under stand conditions, as mostly juvenile trees have been studied in chamber experiments. A synopsis is presented here from an integrated case study which was conducted on adult Fagus sylvatica trees at a Central-European forest site. Employed was a novel free-air canopy O3 fumigation methodology which ensured a whole-plant assessment of O3 sensitivity of the about 30 m tall and 60 years old trees, comparing responses to an experimental 2 × ambient O3 regime (2 × O3 , max. 150 nl O3 l-1 ) with those to the unchanged 1 × ambient O3 regime (1 × O3 = control) prevailing at the site. Additional experimentation on individual branches and juvenile beech trees exposed within the forest canopy allowed for evaluating the representativeness of young-tree and branch-bag approaches relative to the O3 sensitivity of the adult trees. The 2 × O3 regime did not substantially weaken the carbon sink strength of the adult beech trees, given the absence of a statistically significant decline in annual stem growth; a 3 % reduction across five years was demonstrated, however, through modelling upon parameterization with the elaborated database. 2 × O3 did induce a number of statistically significant tree responses at the cell and leaf level, although the O3 responsiveness varied between years. Shade leaves displayed an O3 sensitivity similar to that of sun leaves, while indirect belowground O3 effects, apparently mediated through hormonal relationships, were reflected by stimulated fine-root and ectomycorrhizal development. Juvenile trees were not reliable surrogates of adult ones in view of O3 risk assessment. Branch sections enclosed in (climatized) cuvettes, however, turned out to represent the O3 sensitivity of entire tree crowns. Drought-induced stomatal closure decoupled O3 intake from O3 exposure, as in addition, also the “physiologically effective O3 dose” was subject to change. No evidence emerged for a need to lower the “Critical Level for Ozone” in risk assessment of forest trees, although sensitive tree parameters did not necessarily reflect a linear relationship to O3 stress. Exposure-based concepts tended to overestimate O3 risk under drought, which is in support of current efforts to establish flux-related concepts of O3 intake in risk assessment.
Key words
Ozone flux - dose - exposure - adult Fagus sylvatica trees - ontogeny - free-air fumigation - canopy - scaling - modelling.
References
Fagus sylvatica L.) and Norway spruce (Picea abies L.) trees in a mixed forest stand.
Plant Biology.
(2007);
9
227-241
Scaling water vapor and carbon dioxide exchange from leaves to a canopy: rules and tools. Ehleringer, J. R. and Field, C. B., eds. Scaling Physiological Processes, Leaf to Globe. San Diego; Academic Press (1993): 77-114
(Fagus sylvatica) growing at high altitude in the Bavarian Forest (Germany) in comparison with young beech trees grown in the field and in phytotrons.
Environmental Pollution.
(2000);
109
431-442
Fraxinus pennsylvanica Marsh. and Prunus serotina Ehrh.
Environmental and Experimental Botany.
(1992);
32
33-41
Fagus sylvatica L.) under chronic free-air O3 fumigation.
Plant Biology.
(2007);
9
207-214
Effects of tropospheric ozone on woody plants. Agrawal, S. B. and Agrawal, M., eds. Environmental Pollution and Plant Responses. New York, Boca Raton; Lewis Publishers (2000): 153-182
Ozone air pollution in the Sierra Nevada: distribution and effects on forests. Krupa, S. V., ed. Developments in Environmental Science, Vol. 2. Amsterdam; Elsevier (2003): 402
Tree response to ozone. Lefohn, A. S., ed. Surface Level Ozone Exposures and Their Effects On Vegetation. Chelsea, MI; Lewis (1992): 271-324
(Prunus serotina) trees.
Environmental Pollution.
(2000);
108
297-302
(Betula pendula) leaves as determined by digital image-analysis and X‐ray microanalysis.
New Phytologist.
(1996);
132
135-143
(Betula pendula) under low ozone concentration.
Trees.
(1993);
7
104-114
(Fagus sylvatica) under double ambient O3 concentrations in a free-air exposure system.
Plant Biology.
(2007 a);
9
215-226
15 N and total N in Fagus sylvatica and associated mycorrhizal fungi.
Plant Biology.
(2007 b);
9
242-252
KROCO, Freising, Germany: Canopy research in a temperate mixed forest of Southern Germany. Basset, Y., Horlyck, V., and Wright, S. J., eds. Studying Forest Canopies from Above: The International Canopy Crane Network. Oxford; Smithsonian Tropical Research Institute and UNEP (2003): 71-78
Quercus rubra L. foliage: differential sensitivity to ozone exposure.
Tree Physiology.
(1994);
14
1351-1366
Physiological processes and plant responses to ozone exposure. Sandermann, H., Wellburn, A. R., and Heath, R. L., eds. Forest Decline and Ozone, a Comparison of Controlled Chamber and Field Experiments , Ecological Studies 127,. Berlin; Springer-Verlag (1997): 317-368
Die geschichtliche Entwicklung des Buchen-Vorbaus in Deutschland. Kalkkuhl, R. and Schmidt, A., eds. Waldumbau von Nadelholzreinbeständen in Mischbestände durch Buchen-Voranbau und Buchen-Voraussaat, Vol. 13, Schriftreihe der Landesanstalt für Ökologie, Bodenordnung und Forsten, Landesamt für Agrarordnung Nordrhein-Westfalen, Münster. (1997): 7-16
Fagus sylvatica under experimental free-air ozone exposure.
Environmental Pollution.
(2005);
137
476-482
Fagus sylvatica L.) trees.
Plant Biology.
(2007);
9
253-264
(Betula pendula) saplings.
Environmental Pollution.
(2003);
124
485-495
FACE systems for studying the impacts of greenhouse gases on Forest Ecosystems. Karnosky, D. F., Scarascia-Mugnozza, G., Ceulemans, R., and Innes, J. L., eds. The Impacts of Carbon Dioxide and Other Greenhouse Gases On Forest Ecosystems. Vienna; CABI Press (2001): 297-324
3 moderates responses of temperate hardwood forests to elevated CO2 : a synthesis of molecular to ecosystem results from the Aspen FACE project.
Functional Ecology.
(2003);
17
289-304
Quercus rubra.
.
Water, Air, and Soil Pollution.
(1995);
85
1317-1324
2 .
Science.
(2005);
309
1360-1362
2 and/or O3 concentrations throughout two subsequent growing seasons.
Global Chance Biology.
(2005 a);
11
1387-1401
2 and/or O3 on intra- and interspecific competitive ability of aspen.
Plant Biology.
(2007);
9
342-355
(Betula pendula) .
New Phytologist.
(1997);
137
389-397
Ozone responses of trees: results from controlled chamber exposures at the GSF phytotron. Sandermann Jr., H., Wellburn, A. R., and Heath, R. L., eds Forest Decline and Ozone. Berlin, Heidelberg, New York; Springer (1997): 163-200
Fagus sylvatica L.) in environmental chambers.
Trees.
(1996);
10
268-275
(Fagus sylvatica) .
Trees.
(2006);
20
539-548
3 flux-related responsiveness of photosynthesis, respiration, and stomatal conductance of adult Fagus sylvatica to experimentally enhanced free-air O3 exposure.
Plant Biology.
(2007);
9
197-206
Phytophthora citricola .
Plant Biology.
(2005);
7
640-649
2 ), ozone (O3 ), and ultraviolet-B (UV‐B) radiation on plant diseases.
Environmental Pollution.
(1995);
88
219-225
(Betula pendula) caused by low ozone concentrations.
Trees.
(1991);
5
5-13
13 C in leaves and stem, and phloem structure of birch (Betula pendula) under low ozone concentrations.
Trees.
(1992);
6
69-76
Response mechanisms of conifers to air pollutants. Smith, W. K. and Hinckley, T. H., eds. Physiological Ecology of Coniferous Forests. Physiological Ecology Series, New York; Academic Press (1995 a): 255-308
Betula pendula .
Tree Physiology.
(1995 b);
15
159-165
Ozone and the forests in Austria and Switzerland. Sandermann Jr., H., Wellburn, A. R., and Heath, R. L., eds. Forest Decline and Ozone: A Comparison of Controlled Chamber and Field Experiments , Ecological Studies 127,. Berlin; Springer-Verlag (1997): 95-134
3 stress in forest trees.
Plant Biology.
(2006 c);
8
11-17
3 flux concept for European Forest trees.
Environmental Pollution.
(2006 a);
How sensitive are forest trees to ozone - new research on an old issue. Omasa, K., Nouchi, I., and De Kok, L. J., eds. Plant Responses to Air Pollution and Global Change. Tokyo; Springer-Verlag (2006 b): 21-28
(Betula pendula) . II. Carbon balance, water-use efficiency and nutritional status of the whole plant.
Trees.
(1997);
12
11-20
Methods for controlled and field ozone exposures of forest tree species in North America. Sandermann Jr., H., Wellburn, A. R., and Heath, R. L., eds. Forest Decline and Ozone: A Comparison of Controlled Chamber and Field Experiments , Ecological Studies 127,. Berlin, Heidelberg, New York; Springer (1997): 277-315
(Fagus sylvatica) .
Environmental Pollution.
(2005 b);
137
494-506
3 sensitivity with mature forest tree responses (Fagus sylvatica and Picea abies).
.
Tree Physiology.
(2006 a);
26
1391-1403
(Betula pendula) dry mass within a five year period.
Water, Air, and Soil Pollution.
(2001);
130
947-952
(Betula pendula) saplings exposed to low concentrations of ozone.
Tree Physiology.
(1996);
16
597-605
Betula pendula Roth.) clones as affected by low ozone exposure.
Annals of Botany.
(1995);
75
285-294
2 ameliorate tree response to ozone? A review on stomatal responses.
Environmental Pollution.
(2005);
137
483-493
Defense strategies against ozone in trees: the role of nutrition. Agrawal, S. B. and Agrawal, M., eds. Environmental Pollution and Plant Responses. New York, Boca Raton; Lewis Publishers (2000): 223-245
Quercus rubra L.
New Phytologist,.
(1993);
125
373-379
Quercus rubra seedlings and mature trees after three seasons of ozone exposure.
Environmental Pollution.
(1996);
91
317-320
Scaling up from molecular to ecological processes. Sandermann, H., ed. Molecular Ecotoxicology of Plants , Ecological Studies 170,. Berlin; Springer Verlag (2004): 207-226
Forest decline and ozone: synopsis. Sandermann Jr., H., Wellburn, A. R., and Heath, R. L., eds. Forest Decline and Ozone: A Comparison of Controlled Chamber and Field Experiments , Ecological Studies 127,. Berlin, Heidelberg, New York; Springer (1997 b): 369-377
13 C in Betula pendula .
Oecologia.
(1995);
103
397-406
Plant life forms and their carbon, water, and nutrient relations. Lange, O. L., Nobel, P. S., Osmond, C. B., and Ziegler, H., eds. Physiological Plant Ecology, Vol. II , Encyclopedia of Plant Physiology 12B,. Berlin; Springer Verlag (1982): 615-676
The role of carbon balance and branching pattern in the growth of woody species. Givnish, T. J., ed. On the Economics of Plant Form and Function. Cambridge; Cambridge University Press (1986): 585-602
(Picea abies) on acid soils, Ecological Studies 77. Berlin; Springer-Verlag (1989): 475
Picea abies L.).
Plant Science.
(1988);
57
113-117
Diagnostics in beech exposed to chronic free air O3 fumigation. 2. Comparison between young and adult trees at the branch and tree level. Kinnunen, H. and Huttunen, S., eds. Proceedings IUFRO Meting Forests under Changing Climate, Enhanced UV and Air Pollution , Oulu, Finland, 25 - 30 August 2004, University of Oulu,. (2004): 143-150
3 effects in entire tree crowns.
Plant Biology.
(2007);
9
309-319
3 background levels and trends.
Atmospheric Environment.
(2004);
38
3431-3442
Acer saccharum Marsh. and hybrid Populus L. seedlings. II. Diagnostic gas exchange and leaf chemistry.
New Phytologist.
(1993);
124
637-646
Pinus halepensis Mill.
Journal of Experimental Botany.
(1996);
47
1361-1367
Larix decidua Mill.: a comparison between different altitudes.
Tree Physiology.
(1995);
15
253-258
Picea abies and Pinus cembra : a synthesis.
Environmental Pollution.
(2000);
110
415-422
(Picea abies) susceptibility to ozone uptake: a novel approach relating stress avoidance to defense.
Tree Physiology.
(2002 b);
22
583-590
Picea abies [L.] Karst.) across tree age: implications for the sun and shade crown.
Phyton.
(2002 a);
42
245-253
Fagus sylvatica L.) against oxidative stress.
Annals of Forest Science.
(2003);
60
131-135
Exchange of trace gases at the tree - atmosphere interface: ozone. Gasche, R., Papen, H., and Rennenberg, H., eds. Trace Gas Exchange in Forest Ecosystems. Dordrecht; Kluwer Academic Publishers (2002): 211-226
Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) under free-air ozone fumigation.
Plant Biology.
(2005);
7
611-618
matyssek@wzw.tum.de
Editor: J. T. M. Elzenga
