The shelterwood forest system is a natural regeneration method of forest management that supplies the next generation of trees from overstory tree seeds without planting. This method lowers the cost of forest management by reducing the need for artificial reforestation through planting. This means that the understory trees must be preserved from felled trees during harvest.
Click here for original story, The spatial relationship between damaged understory and felled trees in a shelterwood forest
Source: Phys.org