a zone of wound (traumatic) tissue produced by an injured cambium —note 1. traumatic rings tend to be colored dark from associated gums and resins, and include traumatic parenchyma —note 2. intercellular canals and drought cracks may be present —note 3. common causes of traumatic rings are frost (or cold weather occurring after growth is initiated in the spring) and drought; other causes may be fire and lightningThis definition last updated 10/10/2008