Dynamics of mixed lowland forests in Central Bohemia over a 20-year period

The paper deals with the effect of environmental factors and management on various mixed lowland forests in the Mednik National Natural Monument, Czech Republic, over a 20-year period. The objectives were to evaluate the structure, production, dynamics and radial growth in relation to climatic conditions in the mixed hornbeam-oak, herb-rich beech and spruce forest stands. The tree density decreased by 8.5% (to 120-1,364 trees.ha(-1)), while stand volume increased by 28.0% (to 244-767 m(3).ha(-1)) from 1998 to 2018. Large-leaved lime (Tilia platyphyllos Scop.) and Norway spruce (Picea abies /L./ Karst.) showed high variability and sensitivity to climatic factors in radial growth compared to stability and resistance in sessile oak (Quercus petraea /Matt./ Liebl.) and European beech (Fagus sylvatica L.). April, June and July were determined as the most significant months in relation to diameter increment. The synergism of precipitation deficit and high air temperature was a limiting factor of growth in the studied lowland area. 'Ihe frequency of negative pointer years with extremely low radial growth has been increasing recently. Generally, hornbeam-oak stands are characterized by rich structure, high density and lower productivity, herb-rich beech stands represent rich structured productive forests and spruce forests are very productive stands but with low ecological stability.