|5th Needle/Leaf Interlaboratory Comparision Test 2001/2002|
Ursula Busch and Hans Joachim Fermer
State Environment Agency (LUA)
Wallneyer Str. 6 / D-45133 Essen
In co-operation with:
Austrian Federal Office and Research Centre for Forests, Vienna
The Finnish Forest Research Institute, Parkano
Bundesministerium f. Ernährung, Landwirtschaft und Forsten, Bonn
International co-operative Programme Forests of UN-ECE in collaboration with EU initialised a programme for intensive and continuous monitoring of forest ecosystems for Europe in order to realise a better understanding of air pollution processes. An important task in this field is the needle/leaf-analysis of trees, because they serve as bioindicators for nutrition state and damages.
Necessary is the harmonising and the improvement of analytical techniques. A high and comparable laboratory standard in all countries is indispensable for a European-wide survey of forest state. Important steps on this way have been the edition of the "Manual on methods and criteria for harmonised sampling, assessment, monitoring and analysis of the effects of air pollution on forests" (UN-ECE, Hamburg and Prague 1994) and the performance of the first European needle/leaf interlaboratory test on two certified standards (BCR 100-beech leaves and BCR 101 - spruce needles) with 24 laboratories from 21 countries, organised by France in 1993.
The intensive discussion of the forest foliar expert panel in As 1994 ended with the recommendation of a second test with 4 unknown samples (spruce, pine, oak) during the running level-II monitoring programme. It was organised by Germany in 1995/96 and subsequently discussed on expert panels in Vienna 1997. The expert panel in Vienna therefore decided on a complete repetition and authorised the Landesumweltamt North-Rhine-Westfalia (LUA) to organise another interlaboratory test on foliage every two years. The 3rd interlaboratory study with 5 unknown samples (spruce, pine, oak, beech) and its consequences for the analytical quality manegement were intensively discussed in Bonn 1999 and ended with a revision of Part IV "Sampling and analysis of needles and leaves" of the above mentioned manual.
52 Laboratories from 29 European countries took part in the 4th Needle/Leaf Interlaboratory Test 1999/2000. In comparison to the 3rd test, the results show a distinct improvement of analysis quality at European laboratories working on the issue of forestry analysis.5th Needle/Leaf Interlaboratory Test 2001/2002
The percentage of results out of the given tolerable limits decreases for all elements, especially for all mandatory elements. Even for Nitrogen and Carbon, where the limits became much stronger, we do not notice any significant deterioration. The reason may be that according to the suggestions of ICP-Forests some laboratories changed from classical methods to CNS-elemental analysers. But the experiences with these apparatus are probably still too low. This fact may cause also that 25 percent of all Cabon values are out of the limits. We recognize that the number of data sets with carbon increased about 100 percent from the 4th to the 5th ringtest.
Download (pdf-files):Final Report (135k)
Results (mandatory and optional elements) (229k)
Evaluation pretreatment methodes (640k)
Evaluation determination methodes (641k)
Additional elements (38k)