colloquially for trails or paths used primarily for people making day treks on horses, and used primarily on the east coast, whereas out west the equivalent term is simply trail. The United States has few if any formal designations for bridle paths, though horses are generally allowed on most state and federal trails, roads and public routes except where specifically restricted, although rules differ among locations. There is some criticism of trail riding when excess or improper use of trails may lead to erosion, the spread of invasive plants, conflict with hikers, or harassment of wildlife. Off-road or trail activity is usually not permitted, as such activity may also raise the risk of soil erosion, spread weeds, and cause other damage. However, many responsible equestrians, mountain bikers, and off-road motorcyclists, especially those who get involved in these sports by joining an organized club, perform hours of trail maintenance every year. Many organizations also sponsor educational events to teach newcomers about safety, responsible land stewardship and how to improve riding techniques. Equestrian use Many long-distance trails throughout the world have sections suitable for horse riding, some suitable throughout their length, and some have been developed primarily for horse riding. Within the United States National Trail Classification System, equestrian trails include simple day-use bridle paths and others built to accommodate long strings of pack animals on journeys lasting many days. Some trails managed by the U. S. Forest Service and other governmental entities may restrict access of horses, or restrict access during certain times of the year. Access to trails and pathways on private land is generally left to the discretion of the landowner, subject to the general trespass laws of each of the 50 states. Pleasure riding The term pleasure riding may encompass trail riding. This refers to a form of equestrianism that encompasses many forms of recreational riding for personal enjoyment, without any element of competition. Pleasure riding is called "hacking" in United Kingdom, and in parts of the eastern United States and Canada. In other parts of the United States, particularly the American west, the term trail riding is used interchangeably with pleasure riding when on natural trails or public lands. Many horses are suitable for pleasure riding, including grade horses and other animals of ordinary quality and good disposition. Such horses are sometimes called hacks, particularly in those areas where pleasure riding is known as hacking. In recreational