Why do untouched forests have fewer weeds and bushes than the recently cleared land along roadsides?

Untouched forests have fewer weeds and bushes compared to recently cleared land along roadsides because the natural ecosystem of the forest is balanced and established over time, with native plants and trees dominating the environment. In contrast, when land is cleared for roadsides, it disrupts the natural balance, allowing for opportunistic plants like weeds and bushes to quickly colonize the area due to the disturbance and availability of sunlight and nutrients.