A forest is a community of trees and bushes, which extend on a large area and maintain a close interrelationship in ways that their canopy, fauna, soil and climatic conditions create a special ecosystem. 

Forested lands have similar characteristics to forests, but vegetation is more sparse. They are however very important in maintaining biological balance. Most of these areas, if protected from human activity, will often grow into forests. 

Almost one fourth of Greece’s area (25.5% or 3,359,000 hectares) is covered by forests, primarily natural and of high ecological value. Another 23.9% (3,154,000 hectares) is covered by woodlands or forested lands, which often result from the degradation of forests adjacent to urban or tourist areas.

Greece’s intense relief and specific geographical position favour the existence of a rare variety of forest habitats, relative to the country’s area. The diversity of forests is reflected in the wide range of forest formations, from xerophytic Mediterranean ecosystems, alpine forests, to subalpine and high mountain alpine meadows.

The main forest types existing in Greece are:

• Evergreen-sclerophyllous formations (maquis), a mixed system of high evergreen - sclerophyllous bushes  with the following characteristic species: holly oak, strawberry trees, myrtle and junipers. Maquis vegetation is very important, since it protects soils from erosion and provides food and shelter to many animal species. 
• Evergreen forests of low altitudes, which spread at relatively low altitudes of up to 1000 m. and are divided into two subcategories of the thermophilous conifers (eg Aleppo Ppine, Calabrian Pine, Umbrella Pine, etc.) and evergreen oaks (eg . Holly and Holm Oak), which occur both as trees and as bushes.
• Mixed deciduous forests, dominated by downy oaks, sycamore maples and linden trees. 
• Mountainous conifer forests with characteristic firs. An endemic species, the Greek Fir, results in the natural hybrid Abies borisii regis when crossed with the European Fir. This formation occurs in Black Pine ecosystems.
• Beech and boreal conifer forests, dominated by Greek Fir, Black Pine, Birch, etc. 

Equally important forest formations are the following: 

• Riparian forests, whose presence is dependent on the presence of water. They consist of deciduous trees and shrubs, such as poplars, willows, sycamores, lindens, etc.
• Garrigue - low shrubs (mostly aromatic) which withstand high temperatures and droughts. Scrubland vegetation is typical of Mediterranean ecosystems and usually results from the degradation of pre-existing maquis and forest vegetation. It grows mainly in poor, rocky soils or in repeatedly burned areas. When protected from human threats (eg, overgrazing, fires), the existing vegetation and soil can be restored. The most popular qarrigue species are: thyme, heath, asparagus, daffodil, etc.

Apart from the numerous endemic and rare species of birds, reptiles and insects that live in Greek forests, extremely valuable and important is the variety of mammals. The most famous forest mammals are the Red Deer, the Brown Bear, the Golden Jackal, the Grey Wolf, the Boar and the Badger.

Values of healthy forests
The value of forests is multiple and varied. Humans depend on forests for food, shelter, recreation and work. Apart from their aesthetic, cultural and recreational value, forests are ecologically very important since they: 

• produce oxygen and bind carbon dioxide and other harmful substances 
• diffuse more enjoyable and relaxing light 
• preserve the local climate of by alleviating extreme temperatures. Forests act as “natural air conditioners”. 
• reduce wind and noise, 
• retain rainwater, thus enriching aquifers and preventing floods 
• improve water quality, since they act as chemical and microbiological natural water filters 
• retain soil and prevent erosion 
• maintain and increase soil moisture  
• preserve nutrients that ensure appropriate conditions for the conservation of many animal organisms 
• help maintain natural balance
  

Threats
Despite their great value, Greek forests face many dangers and threats. Wildfires and encroachment as a result of urban expansion and uncontrolled human activity are definitely the most important threats. Greek forests are gradually replaced by urban, suburban and tourist areas. 

Overgrazing, often followed by fire, is the main culprit behind the bare mountains of Greece. Animals (mainly sheep) that graze freely in forests, damage vegetation, destroy natural regeneration, trample and degrade the soil physical properties. When grazing is mild and sustainably managed, it may prove beneficial for the protection of our forests. 

The absence of a coherent and efficient national forest policy, lack of forestry management and the degeneration of the Forest Service are factors that accentuate the problems of Greek forests.

Forest protected areas
The establishment of protected areas has proved an invaluable tool for the aversion of critical degradation of Greece’s forest ecosystems. Designated as national parks, wildlife refuges and protected landscapes or listed as Natura 2000 areas, important forest ecosystems enjoy legal protection. Enforcement however of the legal protection provisions is still low, primarily due to the absence of an effective wardening system and the constantly reduced management by the responsible authorities.

The most important forest protected areas are the following:

• Dadia Forest National Park
• Olympus National Park
• Norhern Pindos national park
• Virgin Forest of Fraktos, Rhodope mountain range 
• Mount Oiti National Park
• Mount Parnitha National Park
• Samaria Gorge National Park
• Parnassos National Park