Gunkanjima used to be regarded as a totally lifeless and artificial island. But this is not true. Certainly there are no tall trees, but in the residential area after the war they managed to make small flower gardens, rooftop vegetable gardens, and green houses using any available space. In the working area, the rock wall was ivy covered. Otherwise no plants were seen on the concrete paved streets, in the square or in the school ground immediately after the mine was closed. But after ten years, the upper parts of wooden concrete buildings (No. 8, 17, 18) have become ivy-covered and the ground, the park and the courts of apartment blocks are overgrown with weeds. As a result, salt spray and rain do not dry up and this accelerates the weathering. Above all the veranda of building No. 8 which has a wooden floor covered in concrete is seriously damaged. It became wholly ivy-covered and the wooden parts got rapidly rotten after eight years and were almost ruined after ten years. Therefore this damage was caused not by the weathering of reinforced concrete structure but b y the decay of wooden structure. It is a good example of weathering caused by plants. According to the report written by Sadako Matsumura in 1936, areas of bare earth along the roadsides were covered with concrete in order to prevent weeds from growing. It is said that this was done to prevent the roots of plants from undermining the revetment wall.