Anna Butcher
Why and how do fallen trees, such as this white gum from Western Australia (pictured above), grow stems vertically from a horizontal trunk?
Pat French
Telford, Shropshire, UK
Two major factors that contribute to the specific shape of a tree are its genetics and the flow of auxins, their growth hormones.
A tree inherits the density, position and angle of its buds from the DNA of its species. In early years, branches may be staggered or paired depending on bud position and orientated by their angle to give a typical tree shape.
However, there is also the auxin effect. These…
