A lean does not automatically make a tree unsafe. Many trees grow with a natural lean for decades. A new or increasing lean, particularly with root or soil movement, is more concerning.
Natural lean versus recent movement
A long-standing lean with adaptive growth differs from a tree that shifted after wind, saturated soil or root damage. Recent change is important history.
Warning signs
Soil lifting, exposed or broken roots, cracks near the base, sudden canopy movement, storm damage or a recently increasing lean should be assessed promptly.
Targets matter
The same defect has different consequences in an open field versus over a bedroom, driveway, road or neighbouring property.