Related Experiment Videos
Northern environment predisposes birches to ozone damage
E Oksanen1, S Kontunen-Soppela, J Riikonen
1Department of Biology, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland. elina.oksanen@joensuu.fi
Plant Biology (Stuttgart, Germany)
|July 26, 2006
Summary
Ozone exposure negatively impacts silver birch growth, with simple exposure metrics being insufficient for risk assessment. Site-specific factors and climate change interactions are crucial for accurate evaluation of ozone damage in birch trees.
Area of Science:
- Environmental science
- Forestry
- Plant physiology
Background:
- Silver birch (BETULA PENDULA Roth) sensitivity to ozone has been studied since the early 1990s in Finland.
- Previous research indicates a need for more refined methods to assess ozone impact on forest ecosystems.
Purpose of the Study:
- To evaluate the effectiveness of different ozone exposure indices for silver birch.
- To identify key factors for developing accurate, flux-based ozone risk assessment models for birch.
Main Methods:
- Long-term open-field experiments were conducted.
- Non-destructive growth indicators, including basal diameter and stem volume increment, were measured.
- Ozone impact was analyzed against Accumulated Ozone dose (AOTX).
Main Results:
- Annual percentage reduction in basal diameter and stem volume increment were the best non-destructive indicators of ozone impact against AOTX.
- Differences in defense strategies, stomatal conductance, and phenolic compounds suggest external exposure indices are inadequate.
- Increasing CO2 may mitigate negative ozone effects, while spring frost can worsen ozone damage.
Conclusions:
- Flux-based ozone risk assessment for birch requires site-specific parameters like G(max) and G(dark).
- Further model development needs to incorporate detoxification capacity, leaf aging, and cumulative ozone impact.
- Climate change factors, such as elevated CO2 and frost, must be integrated into future ozone risk assessments for silver birch.