Forest decline declining forests

Plants may be affected by indirect modifications of the environment. Soil acidification, for example, can cause the leaching of nutrients, and the release of toxic aluminum. These effects may operate together to produce nutrient deficiencies or imbalances to plants. High soil concentrations of aluminum may prevent uptake and utilization of nutrients by plants.Increased availability of aluminum in soils has been implicated as a cause of forest declines in both Europe and the United States, possibly through the toxic effects on small feeder roots 14),... 

Forests in particular must endure the combined stresses imposed by climatic extremes/changes, invasion of insects and diseases, and forest management practices in addition to the added stress of acidic pollutants. All of these stresses modify forest health and productivity. Under this complex situation, it has not been possible to establish the exact role that acidification has had on forest decline nor to develop critical deposition levels at which damages are believed to become important 14), However, the geographical coincidence of forest decline and elevated levels of acidic pollutants offer strong evidence that a linkages exists. 

Cowling, E. Krahl-Urban, B. Schimansky, C. In Forest Decline] Krahl-Urban, B. Brandt, C.J. Schimansky, C.S. Peters, K. Eds. Assessment Group of Biology, Ecology and Energy of the Jiilich Nuclear Research Center Jiilich, FRG, 1988 pp 120-125. 

Forest Decline Program, Botany Department, University of Vermont, Burlington, VT 05405... 

Contemporary forest declines were initiated about 1950-1960, virtually simultaneously throughout the industrial world at the same time as damage to aquatic systems and structures became apparent. A broad array of natural and anthropogenic stresses have been identified as components of a complex web of primary causal factors that vary in time and space, interact among each other, affect various plant growth and development systems and may result in the death of trees in mountainous ecosystems. As these ecosystems decline, the alterations in forest ecology, independent of the initial causal complex, become themselves additional stress factor complexes leading to further alterations. 

Obviously, one looks for causes. That declines in one or another species have natural factor etiologies is unequivocal. The demise of American elms and of the chestnut were due to natural factors. Insect infestations, bacterial and fungal diseases, hurricanes, floods, freezes, droughts and many other stresses can cause extensive tree death (5). But in such declines typically only a single species is affected or climatic events caused decline in a delimited area. In almost all declines caused by natural events, the causal factors can be identified we know their precise etiologies. Natural events are always part of the natural environment and must be factored in when evaluating forest declines (Table I). 

The initial causes of forest decline - natural and anthropogenic - have resulted in a forest decline syndrome that is, per se, a new series of causal factors whose consequences are themselves new causes for ecosystem alteration. 

KLEIN PERKINS Long-Term Fates of Declining Forests... 

Acknowledgments. Research and preparation of this manuscript supported by the R. K. Mellon Foundation and the Vermont Agricultural q)eriment Station. Data obtained from research of Forest Decline Project participants, including Gregory Adams, Mark Easter, Maureen Jennings, Mark Hemmerlein and Heiko liedeker. 

Forest Decline and Air Polhitioru A Study of Spruce (Picea abies) on Acid Soils. Schulze, E.D. Lange, O.L. Oren, R, Eds., Springer-Verlag Berlin. 1989. 

Spruce, Picea abies, Germany, 1984 Declining spruce forest ... 

Backhaus, B. and R. Backhaus. 1986. Is atmospheric lead contributing to mid-European forest decline Sci. Total Environ. 50 223-225. 

Durka W, Schulze ED, Gebauer G, VoerkeUus S (1994) Effects of forest decline on uptake and leaching of deposited nitrate determined from N and 0 measurements. Nature 372 765-767... 

The toxicity of aluminum has been recognized most clearly by the development of bone disease caused by deposition of A1 in bones of patients on hemodialysis and in infants on intravenous therapy/ 6 Excessive A1 in the water used for dialysis may also cause brain damage. Dietary aluminum may be one cause of Alzheimer s disease/ h but this is controversial as is a possible role of aluminum in vaccines in causing inflammation in muscle.1) Solubilization of soil aluminum by acid rain has been blamed for the decline of forests in Europe and North America,) for the death of fish in acid waters,k and for very large reductions in yield for many crops/ An aluminum-resistant strain of buckwheat makes and secretes from its roots large amounts of oxalate which binds and detoxifies the Al3+ ions. ... 

Rippen G, Zietz E, Frank R, et al. 1987. Do airborne nitrophenols contribute to forest decline Environ Technol Lett 8 475-482. 

Cape JN, Freersmith PH, Paterson IS, Parkinson JA, Wolfenden J. 1990. The nutritional status of Picea abies (L) Karst across Europe, and implications for forest decline. Trees Struct Funct 4 211-224. 

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