Yellowstone National Park, in Wyoming, USA, is a popular vacation place. But in the summer of 1998, it was a danger to visitors. Why? The place visited for its beautiful sights was on fire. The park soon closed to the visitors. Fires burned(燃烧) for almost four months. Lots of plants and animals died in the fire. By the end, about 45% of the park had burned.
Although wildfires can be bad for the environment, they are also an important part of the ecosystems(生态系统)。Some forests can get crowded for other trees that not much sunlight reaches the forest floor. This makes it hard for other plants to grow. Fires can make these forests less crowded so that trees, seedlings, and wildflowers can grow.
Wildfires also help forests by burning leaves and plants on the ground. It will add nutrients（养分）to the soil, which helps plants grow.
Wildfires help forests in another way, too. Some evergreen trees can release（释放）their seeds in a forest fire！The fire reaches to even the top of the highest trees. After the fire, new trees start to come out.
A forest is a busy place after a wildfire. New plants begin to grow. The soil is rich with nutrients, and more sunlight reaches the ground. This helps the new plants grow quickly. When plants come back to a forest, animals are not far behind. New flowers bring insects, birds, and other animals. The animals use the plants for food. They also help spread the plants' seeds. This helps the forest grow back even faster. Many animals make their homes in trees after a fire. The forest quickly becomes full of life again.
