4.5. Collectors and Collection
The incoming rainfall was measured at a nearby farm 300 m from the throughfall sampling area. A rain gauge
of type SMHI with a diameter of 16 cm and fitted with a wind shelter was used (SMHI 1958), placed with the
opening 1.5 m above ground. A comparison with data obtained with other gauges used in the forest (see below)
showed that the results was usually within the reported range of observations (Nihlgård 1970), although occa-sionally they were 3% lower.
The throughfall was collected in 12 gauges randomly spread in a forested area of 1600 m
2
. The gauges con-sisted of 1-L polythene bottles with a plastic funnel with diameter 15 cm fitted in the lid. A filter of inert glass
wool was placed in the bottom of the funnel to prevent material entering the bottle. To stabilise the gauges, they
were placed on the ground inside metal tubes (diameter 16 cm). The top of the gauges was 30 cm above the
ground.
The rain gauges were emptied after each rain event between December 2, 1966 and November 2, 1967. The
volume was measured and the pH was determined in order to identify samples with impurities. The bottles were
stored cool and then brought to the laboratory on 15 occasions during the measurement period for chemical
analyses.