Transcript Document

The impact of industrial SO2 pollution on north Bohemia conifers
Rydval & Wilson (2012) – Water, Air, & Soil Pollution. doi: 10.1007/s11270-012-1310-6
Miloš Rydval – [email protected], Rob Wilson – [email protected]
University of
St Andrews
School of Geography & Geosciences, University of St Andrews, St Andrews, United Kingdom
Methodology
Aim
Assessing the spatio-temporal impact of atmospheric SO2 pollution from a
single point source of pollution (a coal-fired power station) on conifer treegrowth in the Jizerské Mts. using dendrochronological methods.
Paper number: B53B-0665
Suppression and Distance
Climate model: Modelling of tree growth based
on available temperature (and precipitation data
where applicable) using OLS regression was
used to predict theoretical growth between 19752005 based on the relationship established in the
1940-1974 calibration period.
Sites with similar attributes (e.g. elevation, aspect) were
selected for sampling, with distance from pollution source as
the primary modulating variable.
Sites included 1 Silver fir and 5 (+1 additional dataset ’KRK’
from ITRDB) Norway spruce sites located SE of the power
station.
Gridded climate data were used as climate model inputs and a
composite of 44 regional SO2 datasets were used as SO2
inputs.
Climate + SO2 model: A second model was
developed which also included regional SO2 data
in addition to climate data.
Fig.5: Scatter plot showing a strong positive relationship between
(A) the 1980, and (B) mean of 1975-1985 Norway spruce site ringwidth indices, and distance from Turów
A strong relationship between growth suppression and distance of sites from
Turów was identified (Fig.5).
Results
Tree growth responded mainly to summer
temperatures, although precipitation also had an
additional minor influence at some sites.
Comparing
Jizerské Mts. and
Bavarian Forest
Presence of abrupt, decade-long growth suppression
in all spruce chronologies was observed (Fig.3).
Fig.1: Regional context and site locations
Background
The study region (Fig.1), centrally situated inside the so-called ‘Black
Triangle’ in the heavily industrialised border area of the Czech Republic,
Poland and Germany, is considered to have had some of the highest
levels of atmospheric pollution in Europe in the 1970s and 1980s.
Sites closest to Turów experienced greatest
suppression in 1980 and the following decade.
Analysis of 268 identified missing rings (Fig.4) revealed
increased incidence at sites closest to Turów around
1980, further reflecting stressful growth conditions.
Fig.6: Comparison of Czech
and German conifer sites,
and regional SO2 index /
emissions
Rapid response to high SO2 concentrations suggested
greater significance of direct atmospheric SO2 rather
than an indirect influence through soil acidification
A comparison of SO2 emissions / atmospheric concentrations with spruce and
fir affected by SO2 emissions in the Bavarian Forest, Germany reveal
differences in the timing of growth suppression coinciding with differing
emission regimes (Fig.6).
(Elling et al. 2009).
The 2100 MW Turów power station, in operation since 1962 is fuelled by
locally mined lignite with a high sulphur content and is the dominant
source of regional pollution.
Modernisation of the power station in the 1990s resulted in an 82%
decrease of SO2 emissions, reduction of NOX by 45% and a 96%
reduction of dust pollution (Nordic Investment Bank, 2005).
Unfavourable climatic conditions (e.g. heavy winter
frost) likely 'triggered' a period of growth suppression
in stands stressed by high pollution levels.
Fig.3: Site chronologies together with ‘Climate’
and ‘Climate + SO2’ model results
Conclusions
Local stands exhibited clear signs of environmental stress (Fig.2).
Poor performance of the ‘Climate’ model in the prediction
period indicates a period of divergence manifested as a
weakening of the climate signal (Fig.3).
Marked increase in agreement between modelled and
actual ring-width when SO2 data are included in models.
The mis-fit between actual and modelled growth
post~1992 suggests no return to pre~1980 growth
response despite lower pollution levels.
Unlike spruce, the lower elevation (FIR) site retained a
climate signal, although missing rings suggest increased
and longer-term stress at this site (Fig.4).
Fig.2: Example of Norway spruce ‘telephone
poles’ (standing deadwood) at site 3
The different response of both species between the two regions reflects
influence of regional factors (e.g. distance from pollution source, elevation),
resulting in a complex story.
Fig.4: Number and percentage of
missing rings in site chronologies
• Decreasing influence of pollution on growth suppression with increasing
distance from pollution source.
• Growth suppression detected in 1980 and the following decade was most likely
caused by a combination of high pollution levels and adverse climatic conditions.
• Distinct difference in response between Norway spruce and Silver fir.
• Indication that growth response has not returned to the pre-impact state.
• Difference in timing of response between Jizerské Mts. and Bavarian Forest.
• Influence of pollution as a potential contributor to the ‘divergence problem’
(D’Arrigo et al. 2008) has implications for dendroclimatic reconstructions in regions
affected by pollution.
References: D’Arrigo, R., Wilson, R., Liepert, B., & Cherubini, P. (2008). On the ‘divergence problem’ in northern forests: a review
of the tree-ring evidence and possible causes. Global and Planetary Change, 60, 289–305.
Elling, W., Dittmar, C., Pfaffelmoser, K., & Rötzer, T. (2009). Dendroecological assessment of the complex causes of decline and recovery of the
growth of silver fir (Abies alba Mill.) in Southern Germany. Forest Ecosystem Management, 257, 1175–1187.
Nordic Investment Bank (2005). July Bulletin: cross-border cooperation.URL: http://www.nib.int/filebank/233-2005-1en.pdf.Accessed 15 Dec 2011.