Regeneration of forests, particularly that for conservation of environment or national lands, must be undertaken by the ecological recipe based on the potential vegetation in individual regions. In the tropical forests such as dipterocarp forests in the South-east Asia, a large number (68 - 320 /m²) of juvenile seedlings are found on the forest floors for a certain short period under the dense canopy. These seedlings mostly die due to the lack of enough light but could be utilized as regeneration sources in other areas. As it is very difficult to collect seeds at the right time and to preserve them for a long period, utilization of seedlings in the forest is worth to consider.
Planting seeds in a high density (300 - 3000 /m²) guarantees formation of climax or its approximate forests in a shorter period than on-going, natural regeneration.