Forestry is the art, science, and practice of studying and managing forests and plantations, and related natural resources. Silviculture, a related science, involves the growing and tending of trees and forests. Modern forestry generally concerns itself with: assisting forests to provide timber as raw material for wood products; wildlife habitat; natural water quality regulation; recreation; landscape and community protection; employment; aesthetically appealing landscapes; biodiversity management; watershed management; and a 'sink' for atmospheric carbon dioxide. A practitioner of forestry is known as a forester.
Forest ecosystems have come to be seen as one of the most important components of the biosphere, and forestry has emerged as a vital field of science, applied art, and technology.
Foresters may be employed by industry, government agencies, conservation groups, urban parks boards, citizens' associations, or private landowners. Industrial foresters are predominantly involved in planning the timber harvests and forest regeneration. Other foresters have the specific jobs which include a broad array of responsibilities. For example, urban foresters work within city environments to enhance urban trees with their unique needs.
Some foresters work in tree nurseries growing seedlings for regeneration projects. Others are involved with tree genetics or developing new building systems as forest engineers. The profession has expanded to include a wide diversity of jobs, typically requiring a college bachelor's degree up to the PhD level for highly specialized areas of work.
Traditionally, professional foresters develop and implement "forest management plans". These plans rely on tree inventories showing an area's topographical features as well as its distribution of trees (by species) and other plant cover. They also include roads, culverts, proximity to human habitation, hydrological conditions, and soil reports ecological sensitive areas. Finally, forest management plans include the projected use of the land and a timetable for that use.
Plans for harvest and subsequent site treatment are influenced by the objectives of the land's owner or leaseholder (for instance, a timber company that holds cutting rights to a given tract of land, or the government in the case of state-owned forests). There is an increasing trend to consider the needs of other stakeholders (e.g., nearby communities or neighborhoods, or rural residents living within or adjacent to the forest tract). Plans are developed with the prevailing forest harvest laws and regulations in mind. They ultimately result in a prescription for the harvest of trees, and indicate whether road building or other forest engineering operations are required.
Traditional forest management plans are chiefly aimed at providing logs as raw material for timber, veneer, plywood, paper, wood fuel or other industries. Hence, considerations of product quality and quantity, employment, and profit have been of central, though not always exclusive, importance.
Foresters also frequently develop post-harvest site plans. These may call for reforestation (tree planting by species), weed control, fertilization, or the spacing of young trees (thinning of trees that are crowding one another).
While other duties of foresters may include preventing and combatting insect infestation, disease, forest and grassland fires, there is an increasing movement towards allowing these natural aspects of forest ecosystems to run their course, where possible, usually excepting epidemics or risk of life or property. Foresters are specialists in measuring and modelling the growth of forests (forest mensuration). Increasingly, foresters may be involved in wildlife conservation planning and watershed protection.
Today a strong body of research exists regarding the management of forest ecosystems, selection of species and varieties, and tree breeding. Forestry also includes the development of better methods for the planting, protecting, thinning, controlled burning, felling, extracting, and processing of timber. One of the applications of modern forestry is reforestation, in which trees are planted and tended in a given area.
In many regions the forest industry is of major ecological, economic, and social importance. Third-party certification systems that provide independent verification of sound forest stewardship and sustainable forestry have become commonplace in many areas since the 1990s. These certification systems were developed as a response to criticism of some forestry practices, particularly deforestation in less developed regions along with concerns over resource management in the developed world. Some certification systems are criticised for primarily acting as marketing tools and lacking in their claimed independence.
In topographically severe forested terrain, proper forestry is important for the prevention or minimization of serious soil erosion or even landsliding. In areas with a high potential for landsliding, good forestry can act to prevent property damage or loss, human injury, or loss of life.
Public perception of forest management has become controversial, with growing public concern over perceived mismanagement of the forest and increasing demands that forest land be managed for uses other than pure timber production, for example, indigenous rights, recreation, watershed protection and preservation of wilderness and wildlife habitat. Sharp disagreements over the role of forest fires, logging, motorized recreation and others drives debate while the public demand for wood products continues to increase.