Practical method

The Five Points of the Natural Forest Restoration Method

Dr. Akira Miyawaki, professor emeritus of Yokohama National University, proposed the restoration of natural forests in the world more than 50 years ago and has since been making these forests, all of which have succeeded. This method is known as the Miyawaki Method.

Dr. Akira Miyawaki

The Five Points of the Natural Forest Restoration Method (Miyawaki Method)

  1. Species: Use potential natural vegetation 
  2. Seedlings: Plant young seedlings, not mature trees
  3. Topsoil: Dress the soil with rich organic material and decomposers
  4. Mulch: Mulch thickly with rice straw
  5. Maintenance: Weeding is required for three years after planting

1. Species

The most important point is the species you plant. The trees to be planted must be based on potential natural vegetation (PNV). PNV refers to the vegetation group (forest) that would be growing in the final stage if no human influence were given to the vegetation society. They are the original and indigenous species of each local place.

In Japan, ecological scientists surveyed the entire country to decide the vegetation groups most suitable to each place.

Potential Natural Vegetation Map

2. Seedlings

When using this method, please plant young seedlings grown in plastic pots and not mature trees. Young seedlings with dense root systems developed in the pot will not receive any damage when planted.

Plant young seedlings densely and at random. Plant two to three seedlings in one square meter; the space in between should be 60-70 cm. Different species should be planted side by side, the same as in natural conditions.

Seedling full of dense roots


  The potential natural forest grows on organic substantial soil. Dress the plantation site with topsoil or with organically fertilized soil at a thickness of 20-30 cm. If topsoil is hard to obtain, permeable soil mixed with organic fertilizer can be used instead.

Useful material for the plantation bed

4. Mulch

After plantation, place rice straw or dried grass as mulch. Thick mulching is necessary for the following reasons: to prevent weeds from growing, stop soil from drying up, and protect the site from heavy rains. The mulch eventually becomes fertilizer.

Put rice straw mulch along the contour line

5. Maintenance

Weeding for three years after plantation is the only necessary maintenance for this method. After this term, trees grow up higher than the weeds. Thinning or pruning the trees are basically prohibited. The tree density is decided not by human beings but by the vegetation society.

Remove soil from the weeds’ roots and leave them in the area