Area covered by dominant tree species in the State Forests divided into stand age classes over the years 2007-2008

The dataset contains data illustrating changes in distribution of dominant tree species in the State Forests divided into stand age classes over the years 2007-2008. Information about covered area is provided in ha and  percentage of whole analyzed  area. Dominant speciescan be defined as the species in the stand with the largest share in terms of area, thickness or number.
It should be noted that this only concerns forests managed by the State Forests National Forest Holding.  the span of the age class is 20 years (e.g. age class I – tree stands up to 20 years old, class II – 21 – 40 years, class III – 41 – 60 years, etc.). The average age is determined as a weighted average, with the area in individual age classes and subclasses taken as the weight. The term forest area refers to the area of forests excluding land related to forest management. The main source of information for the study is the Forest Data Bank (www.bdl.lasy.gov.pl).
The dominant tree species included in the dataset are:

So - pine
Św - spruce
Jd - fir
Bk - beech
Db - oak
Gb - hornbeam
Brz - birch
Ol - black alder
Tp - poplar
Os - aspen