Action: Halo ancient trees
Key messagesRead our guidance on Key messages before continuing
- We captured no evidence for the effects of haloing ancient trees on forests.
'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.
As trees reach old age, they become smaller and their canopy becomes sparse because of the dieback of their outermost branches. As a result, ancient trees in dense forest stand the risk of being overtopped by younger, taller trees. Haloing involves the removal of these young, competing trees from around the ancient tree. This may release ancient trees from competition and allow them to survive for longer. However, sudden changes in environmental conditions (such as light availability) due to the removal of the surrounding canopy may also damage or kill ancient trees.