Douglas-fir (Pseudotsuga menziesii) stands and its herb layer in a Czech commercial forests.

Influence of allochtonous stands introduced Douglas-fir (Pseudotsuga menziesii) on understory vegetation was studied on 44 plots in Czechia territory. Stands had to be 60 years old at least. Norway spruce (Picea abies), European beech (Fagus sylvatica), oaks – Sessile and Pedunculate (Quercus petraea and Q. robur) and other commercial tree species (Tilia cordata, Acer pseudoplatanus, Pinus sylvestris and Larix deciduas) stands were chosen to compare. Compared stands had always the same habitat conditions as Douglas-fir plot. Results have shown that Douglas-fir stands have not unambiguous characteristic species of the herb layer, but they show higher increase of nitrophilous species.