Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress

• Published in: Water, air and soil pollution air and soil pollution, 1995-01, Vol.85 (3), p.1269-1274
• Main Authors: Bussotti, F, Ferretti, M, Cozzi, A, Grossoni, P, Bottacci, A, Tani, C
• Format: Article
• Language: English
• Subjects: abscission; abscission zone; acid deposition; air pollution; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; crown; crown transparency; density; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; flowers; Fundamental and applied biological sciences. Psychology; leaf fall; leaves; Mediterranean climate; ozone; petioles; phenology; plant anatomy; plant morphology; Quercus ilex; rain; temporal variation; ultrastructure
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/BF00477156

In order to study the possible interactions between air pollution and climate conditions in Mediterranean evergreen broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Mediterranean broadleaves, so that even the role of non-acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against pollutants.