Closed forests in natural habitats (A–C) and small-scale stands in man-made habitats (D). A Robinia forest regenerating and managed by coppicing in stripes B Planted mixed forest with native Fraxinus excelsior and alien Robinia pseudoacacia C Old Robinia forest overgrown by Fraxinus excelsior and Acer platanoides as a result of spontaneous succession D A spontaneously established mixed stand with Robinia growing in a quarry.