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Biologic Markers of Air-Pollution Stress and Damage in Forests (1989) / Chapter Skim
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Symptoms as Bioindicators of Decline in European Forests
Pages 119-124

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From page 119...
... none of the familiar biotic, edaphic, climatic, and air-pollution causes of stress in forests (fungi, insects, poor soil conditions, drought, storms of various types, or airborne sulfur dioxide or fluoride) appear to provide an adequate explanation for the changes observer!
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From page 120...
... Thus, most well-informed scientists in central Europe share the view that air pollutants are involved, but we share this view largely because no other set of causal and/or contributing factors has so far been found to explain the diverse symptoms observed on the trees themselves. THE IMPORTANCE OF SYMPTOMS AS BIOINDICATORS OF STRESS In human medicine, in the veterinary sciences, and in the study of disease and dysfunction in plants, observations of symptoms are almost invariably the first indicators that something is wrong with the individual organism or the ecosystem in which the individuals live.
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From page 121...
... Thus, the crown becomes very open and transparent, even though the total number of leaves in the whole crown may not be greatly changed (Roloff, 1986~. In Quercus, a similar phenomenon is based on an increased intensity of apical dominance -- leaves are formed by only the most distal buds of much foreshortened sets of branch internodes so that the crown consists of some portions that have a very bushy appearance and other portions that are almost devoid of leaves.
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From page 122...
... Formation of such shoots usually occurs only during the year immediately following the stress. In the case of Waldsterben-affected trees of Picea abies and Picea rubens, however, epicormic branches continue to be formed year-after-year so that they gradually replace the normal branches, which tend to lose their foliage by one or more of the mechanisms described above.
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From page 123...
... Careful study of symptoms with the perspective of discovering clues to the identification of probable causal and contributing factors is one of the special skills of forest pathology. In the case of forest decline in central Europe, the detection of reliable specific symptoms is extremely complicated because of the large number of tree species involved and the very wide range of climatic, edaphic, ecological, and elevational conditions under which the symptoms have been observed.
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From page 124...
... 1986. So stirbt der Wald.
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Key Terms

  • picea abies
  • forest decline
  • epicormic branches
  • common symptom
  • tree crowns

  • crown transparency
  • tree species
  • tree growth
  • branching habit
  • normal foliage

  • foliage symptoms
  • contributing factors
  • primary cause
  • leaf position
  • norway spruce

  • stress factors
  • european larch
  • declining trees
  • recent changes
  • branching intensity

  • untersuchungen zum
  • larix decidua
  • scots pine
  • elevational conditions
  • forest trees

  • pollutant chemicals
  • abies alba
  • airborne pollutant
  • develop herbaceous
  • similar phenomenon


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