The most complex land ecosystem in which various organisms of flora and fauna co-exist and form biocenosis.

Definition as of Forest Act, of 1991, Art. 3:

For the purposes of the Act, a forest is a land:
1) of contiguous area greater than or equal to 0.10 ha, covered with forest vegetation (or plantation forest) – trees and shrubs and ground cover, or else in part deprived thereof, that is:
     a) designated for forest production, or
     b) constituting a Nature Reserve or integral part of a National Park, or
     c) entered on the Register of Monuments;
2) associated with forest management, but occupied in the name thereof by buildings or building sites, water drainage installations and systems, forest division lines, forest roads, land beneath power lines, forest nurseries and timber stores; or else put to use as forest car parks or tourist infrastructure.

Definition as of the European Parliament and Board Regulation No. 2152/2003, of 17 November 2003:

 "Forest" means land with tree crown cover (or equivalent stocking level) of more than 10 % and area of more than 0.5 ha. The trees should be able to reach a minimum height of 5 m at maturity in situ. It may consist either of closed forest formations where trees of various storeys and undergrowth cover a high proportion of the ground, or of open forest formations with a continuous vegetation cover in which tree crown cover exceeds 10 %. Young natural stands and all plantations established for forestry purposes which have yet to reach a crown density of 10 % or tree height of 5 m are included under forest, as are areas normally forming part of the forest area which are temporarily unstocked as a result of human intervention or natural causes but which are expected to revert to forest. The definition of ‘forest’ includes: forest nurseries and seed orchards that constitute an integral part of the forest; forest roads, cleared tracts, firebreaks and other small open areas within the forest; forest in national parks, nature reserves and other protected areas such as those of special environmental,scientific, historical, cultural or spiritual interest; windbreaks and shelterbelts of trees with an area of more than 0.5 ha and a width of more than 20 m. Rubberwood plantations and cork oak stands are included. However, the definition of ‘forest’ excludes: land predominantly used for agricultural practices.

Forest cover (forest cover index)
Percentage of the area covered by forests in the total geographical area of Poland (or any territorial unit: province, county, commune).

National economy sector dealing with forest management, tending, use and renewal in order to permanently utlise timber and other forest products and use other forest values and functions, such as protective, health, recreational, educational.

Collective forest studies comprising natural, technical and economic sciences as the basis for forest management and economy.

Part of a forest district , of an average area of 1.2 thousand hectares, supervised by a forester.