Sampling in a variable environment: selection of representative positions of throughfall collectors for volume and chemistry under three tree species in the UK

Abstract

Throughfall volume and chemistry for three tree species were measured at 10 sites in the UK using funnel collectors under the canopy and in nearby clearings to measure bulk precipitation. Additional collectors were added for several collection periods at each site in turn, in order to test how representative the original collectors were of the site. Both sets of collectors were compared using graphical displays of principal components analyses and, as a result, some of the original set were repositioned. The method was useful in detecting outliers and allowed all elements under investigation to be tested together.