This means they are often the first trees to grow in areas of a forest that have been cleared by logging or forest fires. Over a period of time, the ground is covered with aspen trees. Aspen can multiply quickly because they don't have to rely on seeds for regeneration.
New trees grow from the roots of the aspen tree.
These roots aren't destroyed by fire or logging. This ability to grow new trees from the root system is a big advantage over trees like pine and spruce that must rely on seed dispersal for renewal. As the aspen trees grow, they help create an environment for other plants. They provide shade for shrubs and grasses, and each year they drop thousands of leaves that decay and enrich the soil for other plants. Larger aspen trees have small leaves that allow sunlight to reach the lower levels of the forest.