How much sunlight reaches the floor of a tropical rainforest?

In a tropical rainforest, the dense, multi-layered canopy prevents most sunlight from reaching the forest floor. It is estimated that only about 1 percent of the light received at the top of the canopy penetrates to the ground level.1

This creates a dark, gloomy environment at the surface, which is generally bare of living plants and shrubs. Instead, the ground is typically covered by a layer of rapidly decomposing organic matter, such as fallen leaves. Because of this intense competition for light, most plants in the rainforest are adapted to either capture sunlight in the upper layers or survive in the deep shade of the understory. When a gap in the canopy is created—often due to tree death or wind damage—the resulting increase in solar radiation reaching the forest floor is vital for the regeneration of many plant species, allowing seedlings and saplings to accelerate their growth.1