- Standardsignatur11994
- TitelBiometrical Features of Needles of Scots Pine and Norway Spruce Under Air Pollution - a Trial of Verification of Field Assessment of Crown Transparency : Expertentagung Waldschadensforschung im oestlichen Mitteleuropa und in Bayern
- Verfasser
- Erscheinungsjahr1991
- SeitenS. 378-383
- Illustrationen8 Lit. Ang.
- MaterialUnselbständiges Werk
- Datensatznummer200099157
- Quelle
- AbstractThe results of verification of the field assessment of crown defoliation, performed on the basis of ECE-Manual criteria, by measurements of number and length of needles as well as dry weight of needles-indexes are described. The parameters of needles from the top, upper and middle parts of crown of pine growing in the 1st and 3rd zones of industriogenic stress and of spruce growing in the 3rd zone were compared with the same features in healthy trees growing in unpolluted area. The big differentation in parameters between stands and classes of crown transparency were found. The indexes of dry weight of 1 needle, of dry weight of 1mm of needle and the total dry weight of needles per 1 annual shoot did not confirmed the field assessment of crown defoliation as "classes of damage". For evaluation of tree vitality the above mentioned indexes seem to be more credible than the field-assessed degrees of defoliation of the crown. Status of the crowns transparency is one of the indirect criterions for the estimation of trees vitality in forest damage surveys (1, 3). Total real image of the crown lets observer to conclude about defoliation and to evalute changes in the status of health of trees (2, 4). Number of needles, loss and yellowing of them are treated so far as symptoms for practical classification of the individual trees to different classes of damages (5). The presented study describes the results of measurements of needles of pine and spruce growing under industriogenic stress in order to attain the objectivization the assessed classes of damage. It was assumed that the direct effect of polluants on photosynthesis apparatus as well as the indirect influence of deformed soil habitat are expressed in morphological features of needles (6, 7). The observed trees grew in 3 mature stands - pine (Pinus silvestris) in the 1st and 3rd zones of industriogenic SO2 and NOX threat in louland and spruce (Picea excelsa) in the 3rd zone of SO2 threat in mountain region. The level of immissions, measured as dry gasdeposition of SO2 and NOX (in mg/Quadratmeter/24 hrs), was respectively for Scots pine in the 3rd zone - 11,71 and 0,28, for Scots pine in the 1st zone - 8,79 and 0,15, for norway spruce - 19,45 and 0,13 (8) . The trees were classified on the basis of the appearance of crown according to ECE-Manual criteria (5), into 1st and 2nd classes of crown transparency. The symptoms of defoliation were following - reduced length of shoots, reduced number and length of needles and changed colour of needles. The assessed defoliation was estimated at 20% in the 1st class of damage (warning class) and at 50% in the 2nd class (moderately damaged). Three trees for each class in particular stands were studied and compared with the healthy trees "O" (bit damaged). The trees evaluated as healthy grew in louland, the site conditions like tested trees but in the area..
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