Towards harmonization of forest deposition collectors - case study of comparing collector designs

Abstract

In recent years the harmonization of methods in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) operating under the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP) has been intensified. Among the C-actions of the FutMon project (LIFE07 ENV/D/000218; 2009-2010) the C1-Dep-22(SI) action was established with the goal to harmonize and develop the deposition monitoring procedures and sampling methods. The sampling equipment, spatial design of sampling plots and sampling frequency throughout Europe vary considerably. Therefore a step-by-step approach was made where the harmonized sampling equipment was developed and tested first. The selected collectors were installed at one observation plot of each participating country where measurements of throughfall and bulk deposition were run in parallel with the national collectors for a period of one year. To evaluate the agreement between methods, different statistical analyses were used including Altman-Bland plots, model II regression, and repeated measures ANOVA. Preliminary results from the “Intensive forest ecosystem monitoring plot” plot Brdo in NW Slovenia show a good agreement between national and harmonized bulk (both funnel-type) collectors, while comparison of throughfall measurements indicates systematic bias between harmonized (funnel-type) and national (gutter-type) collectors.