What makes a tree safe?
When it comes to working on trees it is often a highly emotive subject, especially when they are in very public places, and have powerful connections to community. When a tree fails it can have devastating effect, and yet it is common to see sadly unnecessary interventions to healthy trees, simply on the grounds of ‘safety’.
Professional tree inspectors never assess a tree as safe, they will weigh up many factors to judge likelihood of failure. As a complex natural organism, there are external signs that an inspector can use to determine tree health, from a simple bulge in the trunk to a fruiting fungal body within the tree. A rounded bulge to one side can indicate internal decay, or a vertical rib can mean that a long internal crack is present, each of which can alter the structural capabilities. There are aggressive fungi and passive ones, each having unique decay outcomes, telling us much more about the complex event.