In the Northern Hemisphere these forest types are often referred to as "Deciduous Summer Forests" and typically have a 5-6 month growing season that may range from between 150 to 200 days. About 30 to 60 inches of rain falls each year, and is fairly evenly distributed throughout the year. The soils of the deciduous forest are relatively fertile, due to plenty of leaf litter. There is extensive plant diversity in the deciduous forest dominated by broadleaf deciduous hardwood trees such as oak, hickory, maple, ash, beech and others. The forests consist of 3-5 layers, which are relatively open with rich ground flora. There are usually one or two strata of trees, an understory of shrubs, and low growing forbs. Animals that typically inhabit the deciduous forests' of North America are bears, deer, bobcats, raccoons, squirrels, as well as many birds and invertebrates. The greatest concentration of animals is on and just below the forest floor.