New Sampler for Dry Deposition in Forest Canopy

Abstract

A new type of sampler for dry deposition in a forest canopy was designed and tested to confirm its usefulness. The new sampler is made of Teflon chips packed in a nylon net, and tied on a rod like a branch in the canopy. The validity and characteristics of the new sampler were checked by comparing it with the conventional bucket sampler and the foliar extraction method using hinoki (Chamaecyparis obtusa) trees. The comparison between the deposited amounts on the dummy branch and those on the bucket indicates that the dummy could trap gaseous matter more effective than the bucket. From a comparison with the foliar extracting method, it is concluded that the trapping of particulate matter by the new dummy branch is comparable to that of natural needle leaves. However, its efficiency for gaseous matter is relatively small. This disadvantage should be improved by applying other materials to the dummy. Moreover, it is found that the uptake of gas especially SO2 through the stomata is an important point in the discussion about dry deposition. To evaluate the amounts of dry deposition in the forest canopy more precisely, combination with the additional method should be useful.