An orchard is a deliberate planting of trees or shrubs that is maintained for food production. Orchards are usually comprised of fruit- or nut-producing trees that are grown for commercial production. Examples of orchard fruits include apples, pears, oranges, bananas, cherries, and nuts such as pecans, walnuts, and almonds. Orchards can be a feature of large gardens, where they serve both an aesthetic and productive purpose. Orchard activities include pruning the trees, picking the fruit and nuts, checking for insects, and replacing old trees with new ones. Orchards can be laid out in a regular grid, with a grazed or mown grass or bare soil base that makes maintenance and fruit gathering easy. Most modern commercial orchards are planted for a single variety of fruit, but it would be beneficial to introduce some genetic diversity in orchard plantations as well by interspersing other trees through the orchard. Orchards can be complex horticultural systems with a number of landscape characteristics and features or be a relatively simple system with few landscape characteristics.