Sulphur dioxide threshold concentration values for Cladina rangiferina in the Mackenzie Valley, N.W.T.
A simulation model for the prediction of threshold concentration values of gaseous sulphur dioxide for damage to Cladina rangiferina over a 24-h period is presented. The model requires inputs of near surface relative humidities and air temperatures as well as lichen surface temperatures, and nearby...
| Published in: | Canadian Journal of Botany |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | French |
| Published: |
Canadian Science Publishing
1985
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/b85-103 http://www.nrcresearchpress.com/doi/pdf/10.1139/b85-103 |
| Summary: | A simulation model for the prediction of threshold concentration values of gaseous sulphur dioxide for damage to Cladina rangiferina over a 24-h period is presented. The model requires inputs of near surface relative humidities and air temperatures as well as lichen surface temperatures, and nearby airport wind speeds. An initial value of percent lichen water content must also be specified. Studies of lichen water relationships provided expressions utilized in the model for the calculation of the percent lichen water content. The model was applied to four microclimatically different days for an open lichen–spruce woodland near Inuvik, N.W.T. Boundary-layer resistance was found to be not as important as internal thallus resistance to sulphur dioxide uptake. For all days examined, threshold gaseous concentration values of sulphur dioxide for a 24-h period ranged from 20 to 30 μg∙m −3 . |
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