Env Exp Biol (2012) 10: 57–66

Time needed to achieve sufficient richness of structural elements and bryophytes in deciduous forest stands

Abstract

In Northern Europe, one of the tools that has been used in nature conservation is set-aside of the so-called woodland key habitats (WKHs). We determined the period of time after start of passive restoration to attain the threshold quality needed to be recognized as a WKH. Richness of bryophyte species and structural elements in stands with different past history was determined. We found that most of the studied forest stands designated, as WKHs had regenerated after clearcut or selective spruce removal during the last century. Stands (n = 12) were grouped as managed and less-managed WKHs, based on evidence of human disturbance. The term less-managed WKHs was used to describe stands that probably had been regenerated on previous clearcuts or past agricultural land before year 1900. Managed and less-managed stands slightly differed in amounts of coarse woody debris and richness of bryophyte species. The results show that passive restoration of a managed deciduous tree stand, by setting it aside from management in a period of 45 to 90 years, can allow to reach the sufficient biological value, as defined by WKH inventory criteria. However, this amount of time is not sufficient to reconstruct quality of dead wood that is typical of old-growth forests.