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Kritisk belastning av aciditet för skogsmark i norra Tjeckien

Akselsson, Cecilia (1997) In Lunds universitets Naturgeografiska institution - Seminarieuppsatser
Dept of Physical Geography and Ecosystem Science
Abstract
Forest decline is an increasing problem in Europe. "The Black Triangle" area, situated in the mountainous region where the borders of Germany, the Czech Republic and Poland meet, is one of the worst damaged areas. The reasons for the forest dieback are not fully understood, but the soil acidification caused by the burning of sulphur rich coal in the region is considered a major cause.
To reduce the soil acidification the emissions of acidifying compounds must decrease. For this to be possible the decision makers must have some kind of concrete information about the acidification status in different regions. This is the background of the construction of the concept "Critical load of acidity", which is the highest deposition of acidifying... (More)
Forest decline is an increasing problem in Europe. "The Black Triangle" area, situated in the mountainous region where the borders of Germany, the Czech Republic and Poland meet, is one of the worst damaged areas. The reasons for the forest dieback are not fully understood, but the soil acidification caused by the burning of sulphur rich coal in the region is considered a major cause.
To reduce the soil acidification the emissions of acidifying compounds must decrease. For this to be possible the decision makers must have some kind of concrete information about the acidification status in different regions. This is the background of the construction of the concept "Critical load of acidity", which is the highest deposition of acidifying compounds that does not cause long-term harmful effects on specified elements of an ecosystem. By comparing the critical load with the acid deposition, areas where the critical load is exceeded can be identified. Critical load maps give useful information when it comes to decisions to forest soils in the Czech part of "the Black Triangle", have been calculated using the Simple Mass Balance model (SMB). The SMB model is based on a long-term steady state approach using long-term sources and sinks of acidity. The main source of acidity is the acid deposition, and one of the dominating sinks is the weathering of base cations in the soil. The harmful effects on the forest ecosystem can be linked to the acid deposition by specifying a critical limit on the molar ratio between the concentrations of base cations [BC] and aluminium ions [Al] in the soil solution. The critical limit used in this study is [BC]/[Al]=1.0. The critical load is the deposition which ensures that the [BC]/[Al] ratio does not decrease below 1.0 in a long-term perspective.
The critical load was exceeded in 76% of the forest area according to the model calculations, using deposition data from 1992. The highest exceedances were found in the mountains along the Czech border, northwest of Prague. Non-exceedance areas were found in regions with rich soils.
The exceedance of the critical load was compared with forest damages in 13 regions. The coverage fraction of forest with severe damages, expressed as needle loss, in the different regions were plotted against the mean exceedance, the maximum exceedance and the median of the exceedance in the regions. The same type of analysis was performed using the coverage fraction of forest damage related c1earcuts. Relationships were found between the calculated exceedance and forest damage. This was most obvious when the maximum value of the exceedance was used. The magnitude of forest damage degree on 51 permanent plots was compared with the exceedance, but no clear relations were found.
Many parameters are included in the SMB model, and since all parameters inherit uncertainties, the uncertainties in the result can be expected to be substantial. Improvements can be made continuously, when new data, with less uncertainties, become available. Of highest priority are improvements of the weathering data and the deposition data. However, although large uncertainties are accounted for in the calculations, the trends are considered to be reliable. (Less)
Abstract (Swedish)
Skogsskador och skogsdöd är ett växande problem i Europa. "Svarta Triangeln", som ligger i bergsområdet där Tysklands, Tjeckiens och Polens gränser möts, är en av de värst drabbade områdena. I dagsläget saknas kunskap för att kunna förklara skogsskadorna helt och hållet, men markförsurningen i området, som orsakas främst av förbränning av svavelrikt kol i de många kolkraftverken, är troligtvis en starkt bidragande orsak.
För att förhindra en fortsatt markförsurning måste utsläppen reduceras. Detta kräver att beslutsfattarna förses med konkreta fakta om vilka områden som är värst drabbade. Med detta som bakgrund konstruerades begreppet "kritisk belastning av aciditet", som är den högsta deposition av försurande ämnen som inte orsakar... (More)
Skogsskador och skogsdöd är ett växande problem i Europa. "Svarta Triangeln", som ligger i bergsområdet där Tysklands, Tjeckiens och Polens gränser möts, är en av de värst drabbade områdena. I dagsläget saknas kunskap för att kunna förklara skogsskadorna helt och hållet, men markförsurningen i området, som orsakas främst av förbränning av svavelrikt kol i de många kolkraftverken, är troligtvis en starkt bidragande orsak.
För att förhindra en fortsatt markförsurning måste utsläppen reduceras. Detta kräver att beslutsfattarna förses med konkreta fakta om vilka områden som är värst drabbade. Med detta som bakgrund konstruerades begreppet "kritisk belastning av aciditet", som är den högsta deposition av försurande ämnen som inte orsakar långsiktigt skadliga effekter hos en specificerad organism i ett ekosystem. Genom att jämföra den kritiska belastningen med depositionen av aciditet, kan områden där den kritiska belastningen överskrids identifieras. Detta är användbar information vid beslut om utsläppsminskningar.
I denna studie har den kritiska belastningen och överskridandet av den kritiska belastningen i den tjeckiska delen av "Svarta Triangeln" beräknats med "Simple Mass Balance"-modellen (SMB). SMB bygger på en jämvikt mellan försurande processer, främst deposition av aciditet, och processer som motverkar försurningen, bl a baskatjonvittring. Genom att specificera en kritisk gräns på kvoten mellan koncentrationerna av baskatjoner, [BC], och aluminiumjoner, [Al], i marklösningen, kan depositionen av aciditet kopplas till skadliga effekter på ekosystemet. Den kritiska gräns som användes i denna studie var [BC]/[Al]=l.O. Den kritiska belastningen är den högsta deposition som kan förekomma utan att [BC]/[Al]-kvoten understiger 1.0 i ett långsiktigt perspektiv.
Den kritiska belastningen överskreds enligt modellberäkningarna på 76% av skogsmarken i studieområdet, baserat på 1992 års deposition. Det högsta överskridandet fanns i bergsområdet längs gränsen mot Tyskland, nordväst om Prag. Områden där den kritiska belastningen underskreds sammanföll med bördiga jordar.
Överskridandet av den kritiska belastningen jämfördes med skogsskador i 13 områden. Andel skog med svåra skador, uttryckt som stor barrförlust, i de olika områdena plottades mot medelvärdet, medianvärdet och maximumvärdet av överskridandet. Samma typ av analys gjordes med andel skogsskaderelaterade kalhyggen. Samband fanns, både då andel skog med svåra skador och då andel skogsskaderelaterade kalhyggen användes. Sambanden var mest tydliga då maximumvärdet av överskridandet användes. Skogsskadegraden på 51 permanenta provytor jämfördes också med överskridandet men inget tydligt samband påträffades.
SMB innefattar många olika parametrar, alla med ett visst mått av osäkerhet. Detta leder till att osäkerheten i resultatet kan förväntas vara stor. Förbättringar, dvs reducering av osäkerheten, kan göras kontinuerligt, allt eftersom nya och mer tillförlitliga data blir tillgängliga. Av största vikt är att förbättra vittrings- och depositionsdata. Även om resultatet är behäftat med stora osäkerheter kan trenderna i området anses vara trovärdiga. (Less)
Please use this url to cite or link to this publication:
author
Akselsson, Cecilia
supervisor
organization
alternative title
Critical load of acidity to forest soils in the Northern Czech Republic
year
type
H1 - Master's Degree (One Year)
subject
keywords
geografi, naturgeografi, aciditet, skogsmark, norra Tjeckien
publication/series
Lunds universitets Naturgeografiska institution - Seminarieuppsatser
report number
46
funder
Svenska Institutet
language
Swedish
additional info
Andreas Barkman, vid avdelningen för kemisk teknologi på Kemicentrum i Lund.
id
2027126
date added to LUP
2011-11-23 10:40:52
date last changed
2011-11-23 10:40:52
@misc{2027126,
  abstract     = {Forest decline is an increasing problem in Europe. "The Black Triangle" area, situated in the mountainous region where the borders of Germany, the Czech Republic and Poland meet, is one of the worst damaged areas. The reasons for the forest dieback are not fully understood, but the soil acidification caused by the burning of sulphur rich coal in the region is considered a major cause.
To reduce the soil acidification the emissions of acidifying compounds must decrease. For this to be possible the decision makers must have some kind of concrete information about the acidification status in different regions. This is the background of the construction of the concept "Critical load of acidity", which is the highest deposition of acidifying compounds that does not cause long-term harmful effects on specified elements of an ecosystem. By comparing the critical load with the acid deposition, areas where the critical load is exceeded can be identified. Critical load maps give useful information when it comes to decisions to forest soils in the Czech part of "the Black Triangle", have been calculated using the Simple Mass Balance model (SMB). The SMB model is based on a long-term steady state approach using long-term sources and sinks of acidity. The main source of acidity is the acid deposition, and one of the dominating sinks is the weathering of base cations in the soil. The harmful effects on the forest ecosystem can be linked to the acid deposition by specifying a critical limit on the molar ratio between the concentrations of base cations [BC] and aluminium ions [Al] in the soil solution. The critical limit used in this study is [BC]/[Al]=1.0. The critical load is the deposition which ensures that the [BC]/[Al] ratio does not decrease below 1.0 in a long-term perspective.
The critical load was exceeded in 76% of the forest area according to the model calculations, using deposition data from 1992. The highest exceedances were found in the mountains along the Czech border, northwest of Prague. Non-exceedance areas were found in regions with rich soils.
The exceedance of the critical load was compared with forest damages in 13 regions. The coverage fraction of forest with severe damages, expressed as needle loss, in the different regions were plotted against the mean exceedance, the maximum exceedance and the median of the exceedance in the regions. The same type of analysis was performed using the coverage fraction of forest damage related c1earcuts. Relationships were found between the calculated exceedance and forest damage. This was most obvious when the maximum value of the exceedance was used. The magnitude of forest damage degree on 51 permanent plots was compared with the exceedance, but no clear relations were found.
Many parameters are included in the SMB model, and since all parameters inherit uncertainties, the uncertainties in the result can be expected to be substantial. Improvements can be made continuously, when new data, with less uncertainties, become available. Of highest priority are improvements of the weathering data and the deposition data. However, although large uncertainties are accounted for in the calculations, the trends are considered to be reliable.},
  author       = {Akselsson, Cecilia},
  keyword      = {geografi,naturgeografi,aciditet,skogsmark,norra Tjeckien},
  language     = {swe},
  note         = {Student Paper},
  series       = {Lunds universitets Naturgeografiska institution - Seminarieuppsatser},
  title        = {Kritisk belastning av aciditet för skogsmark i norra Tjeckien},
  year         = {1997},
}