This picture shows miniature trees at the top of the volcanic chimney. What is surprising is that they are in fact adult birch trees of may be 20 years old or more. They should be of 20 to 30 m height with a trunk circumference between 40 to 60 cm. The composition of the chimney being of mainly scoriae, lava, cinders, rocks and so on, the roots cannot grow. It is the same principle used with the Bonsaï when men ligatured and cut the roots. The difference is that in volcanic area, it is a natural phenomena.