Bioindication

Conifer needles are frequently used as bioindicators. (Bioindication is a way to monitor environmental conditions, especially pollution, through their impact on living organisms.)

Airborne POPs are trapped efficiently in conifer needles because of the chemical affinity to the waxy needle surface. Moreover, the rough canopy structure of coniferous woodland virtually combs the bypassing air for pollutants.

MONARPOP uses needles from Norway spruce (Picea abies [L.] Karst.) which are harvested from September to October. The needles have thus been exposed to ambient pollution loads for half a year since budburst. This duration allows intercomparison with SPMD samplers ("artificial needles", see section on air sampling). Norway spruce has been chosen as a conifer which can be found throughout the largest part of the alps, often afforested as homogeneous stands which facilitates the selection of standard sites and enhances comparability. Also, bioindication with Norway spruce can rely on the experience and evidence gathered during numerous earlier studies.

A professional tree climber does the harvest.