Stability and Destabilization of Central European Forest Ecosystems—A Theoretical, Data Based Approach
Based on a thermodynamic model of a forest ecosystem, stability is defined as a system in quasi-steady state. The steady state is defined by the balance between ion uptake (phytomass production) and ion mineralization (secondary production) and by the balance between input and output. In steady state, the ion cycle of the system is closed. A de-coupling (opening) of the ion cycle leads to net production or consumption of protons, which causes changes in the chemical soil environment. Resilience is defined as the ability of the system to maintain the H+ /OH− balance. Several buffering mechanisms operate in soils and organisms to maintain this balance. The various buffer rates are critical in regulating system resilience. The natural climatic variation, the necessity to re-establish system elements continuously, and the biomass utilization by man lead to a de-coupling of the ion cycle and thus produce chemical stress. A sequence of ecosystem states exist: aggradation, stability with high resilience, humus disintegration, stability with low resilience, buildup of decomposer refuge, and podzolization. From the data known about rates of proton loading and proton buffering, it must be concluded that acid deposition shifts forest ecosystems from stability ranges into destablization phases (transition states), even at low rates of deposition.
KeywordsForest Ecosystem Mineral Soil Acid Deposition Cation Acid Silicate Weathering
Unable to display preview. Download preview PDF.
- Bache, B.W. 1983. The implications of rock weathering for acid neutralization. Pages 175–187 in Ecological effects of acid deposition. Nat. Swed. Environ. Prot. Board, Rep. SnV pm 1636.Google Scholar
- Mazzarino, M.J., H. Heínrichs, and H. Fölster. 1983. Holocene versus accelerated actual proton consumption in German forest soils. Pages 113–123 in B. Ulrich and J. Pankrath, eds. Effects of accumulation of air pollutants in forest ecosystems. Reidel, Dordrecht, The Netherlands.CrossRefGoogle Scholar
- Prigogine, I. 1947. Etude Thermodynamique des Processus Irreversibles. Desoer, Liege, Belgium.Google Scholar
- Tamm, C.O., and G. Wiklander. 1980. Effects of artificial acidification with sulphuric acid on tree growth in Scots Pine forest. Pages 188–189 in D. Drabls and A. Tollan, eds. Proc. Int. Conf. Ecol. Impact Acid Precip. SNSF-project, Oslo-As, Norway.Google Scholar
- Ulrich, B., R. Mayer, and P.K. Khanna. 1979. Deposition von Luftverunreinigungen und ihre Auswirkungen in Waldökosystemen im Solling. Schriftenr. Forstl. Fak. Univ. Göttingen 58, Sauerländer, Frankfurt, W. Germany.Google Scholar