Some cracked trees can be managed; others have lost too much structural integrity. The answer depends on where the crack is, how far it extends, the size of affected stems, decay and what could be struck.
Fresh cracks need attention
A new crack after wind or heavy loading can indicate active movement. Keep people away from the potential failure zone until the tree can be assessed.
Can cables fix a split?
Support systems can reduce movement in selected trees but are not a universal repair and do not restore a damaged union to its original condition.
When removal becomes more likely
Severe separation, major decay, root failure, repeated failures or an unacceptable target situation can make removal the more practical risk-management option.