Consequently, forest management practices, in particular logging (both authorized and illegal), concentrate on the most accessible areas, directly adjacent to existing regular transport roads. In 2009, as much as 80.6 per cent (840,908.8 ha) of forest surface area harbouring some 77.2 per cent (estimated at 584,771 ha) of the total timber stock was classified as productive forests, while the remaining 19.4 per cent (201,881.2 ha) with 22.8 per cent (estimated at 172,490 ha) of the timber volume was classified as non-productive forests. However, forest productivity is estimated to be much lower than in some other European countries, partly due to different forest degradation factors and human pressures on forest ecosystems. Moreover, the more accessible forest stands have been significantly degraded through overharvesting and overgrazing, which has changed the forest age structure and species composition, and reduced the forest underwood.