Thin, dense lateral twigs of different sizes, called witches' brooms, are an unusual aspect of biodiversity, and these interesting objects should also be protected. In Ukraine, they are particularly associated with pines, and take the form of dome-shaped trees with dense needles. Witches' brooms develop in the lower, middle or upper part of the tree, reach 5-10 m long, and are associated with trees of different age, including those one hundred years old. Various factors are thought to be responsible for witches' broom formation, including viruses, bacteria, mycoplasma infections and other pathogens. The present study was made to discover whether witches brooms can be caused by genetic mutations in the buds and be heritable. Cones were collected from witches' brooms on 100-year-old Pinus sylvestris. The seeds were then sown in a nursery simultaneously with seeds from unaffected plants of the same age as controls. Both experimental and control seedlings were planted out at one year of age into a young pine stand. Good care was taken of the young plants in the stand, including treatment with Bordeaux mixture. The sizes of twigs and needles were measured. Experimental plants found to be 2-2.5 times smaller than controls, with shorter needles and an appearance like the witches' brooms of their parent trees. Our research suggests that seeds formed within witches' brooms have heritable characteristics which are different from those connected with infectious diseases. The unusual plants which result can be grown in arboreta and parks as examples of an interesting biodiversity phenomenon.