Do exotic trees have less arboreal lichen than native coniferous trees? : A field study on occurrence of arboreal lichen on exotic tree species used in forestry research in northern Sweden | Har främmande trädslag färre hänglavar än inhemska barrträd? : En fältstudie på hänglavars förekomst på främmande trädslag från ett skogsbruksförsök i norra Sverige
2025
Magnusson, David
The arboreal lichen density on five exotic tree species and the reintroduced Larix sukaczewii grown in harsh climate in boreal Sweden was measured and compared to the native coniferous trees in the area. This was to investigate whether the exotic trees could be sufficient hosts to arboreal lichen, which are an increasingly important food resource for reindeer, in areas where forest rejuvenation has proven to be difficult. Data was collected by estimating lichen density on a scale ranging from 0 to 3, where 0 = no lichen, and 3 = frequently occurring. Tree species, diameter at breast height (DBH) and temperature sum were then used as variables in a multinomial logistic regression to test whether they affect the occurrence of arboreal lichen. The native Norway spruce (Picea abies) has the highest odds of having high density of arboreal of lichen. Some exotic tree species, e.g., white spruce (Picea glauca), show higher odds of high lichen densities in some cases compared to both Norway spruce and Scots pine. While temperature sum and DBH had small effects on the odds of a tree species having more or less lichen, there was some variance between study sites in their effect on lichen density. This is most likely due to the landscape configuration surrounding the studied plots, which will affect lichen occurrence as well as how well lichen fragments can be dispersed to new habitats.
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