抄録
On the present experiment by the windtunnel method the writer investigated, using various model fences, the breaking effects when many windbreaks were set in lavers and when the windbreaks which had a great deal of openings at the lower part as the row planting of pine tree was helped by the hedge of a dwarf plant. The results obtained were as follows: 1. When the fences which have openings and have no vortex region on the leeward are set in layers, the more the fences are used in layers, the more effective they are. On the country when the fences which have few openings and have some vortex regions on the leeward are used in layers, its breaking effect don't almost increase. 2. To help the windbreak which have a great of openings on lower part, it is desirable that the location of hedge comes near the main windbreak, though there are no difference on the leeward and on the windward.
