nickname is the evergreen state Why that?

Washington state is nicknamed the "Evergreen State" because of its extensive evergreen forests. The state's western slopes are home to lush rainforests, while the eastern slopes are covered in drier, more open woodlands. The state is also home to several national parks and forests, including Mount Rainier National Park, North Cascades National Park, and Olympic National Park. Washington's evergreen forests provide a variety of benefits, including clean air and water, habitat for wildlife, and recreational opportunities.