Survey of some attributes of post-agricultural lands in Polish State Forests

Based on materials gained in March 2015 from the Forest Data Bank the survey of some attributes (forest address including Regional Directorate of State Forest (RDSF), area in hectares, soil unit, forest site type, dominant species in a forest stand and age of the dominant species in a stand) of post-agricultural lands occurring in Polish State Forests was conducted in the paper. Distribution of post-agricultural lands in Poland by RDSF as well as the structure of soil units, forest site types, dominant tree species and the age of the species was presented and analyzed in the article. Distribution of post-agricultural lands is not regular in regions of Poland as the highest share of such lands in the total area of State Forests was stated for a northern part of the country (RDSF in Szczecinek, Piła and Olsztyn) and the lowest for central-southern regions (RDSF in Katowice, Radom and Kraków). In spite Brunic Arenosols distinctly prevail in cover of post-agricultural lands occurring in State Forests (65.8%) the soil unit is not the dominant one in all regions of Poland. Namely, in RDSF located in mountainous and upland areas Cambisols and Luvisols predominate. In terms of forest site types structure, mesotrophic sites clearly prevail in post-agricultural lands as two forest site types (fresh mixed coniferous forest and fresh mixed broadleaved forest) cover 62.4% of all such lands. In spite Scots pine (Pinus sylvestris L.) is the main tree species overgrowing post-agricultural soils in Polish State Forests the share of the species in young plantations established in last two decades has clearly decreased. It has resulted from appearing since 1990s an increasing importance of ecologisation of forestry in Poland what has been reflected e.g. in a distinctly increase of a share of broadleaved species in young plantations introduced on post-agricultural lands in last decades. The trend has especially pertained oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica) of which much higher share was stated for the youngest analyzed age class (<20 years) of post-agricultural woodlands than for older forest stands.