Bark splitting on trees may be caused by various forms of stress.
- Wind:- High winds may physically push branches or stems to the point where the bark is overstretched, causing a split.
- Environmental:- Pollution may be a detrimental factor in tree physiology causing stress. Sudden changes in climate such as a long dry period followed by an excessive wet period may cause internal stress as the tree adapts from one weather pattern to another.
- Fungal:- Some types of fungus can cause bark splitting as it becomes established in the tree, interfering with normal physiology.
- Insect:- Sometimes insects may cause bark splitting if an attack is severe.
Often seen in bark splits by any cause is a resin type substance. This is called by different names in different species. For example, it is called Kino in Eucalyptus trees, Gum in Wattles trees and Resin in conifers.
It is a defence substance produced by the tree in an attempt to seal bark splits to prevent insects or fungus entering and causing problems for the tree. If an insect or fungus has already entered the bark split, the Kino, Gum or Resin may be able to seal the organism in, thereby destroying it.
Prehistoric Amber is petrified resin which has trapped insects and preserved them for millions of years.