You can probably imagine the usual situations when you'd consult an arborist. Perhaps you want a tree to be removed (or even moved), or you need to have the health of the tree professionally assessed so it can get the care it needs. But why would anyone need to call an emergency arborist?
If an emergency arborist has a busy period, it's after inclement weather. The service assesses the stability of larger trees that have been destabilized due to extreme weather. There's no universal rule about whether a tree has become dangerous, which is why each case needs an individual assessment—and may need one in an emergency capacity.
Stabilization of the tree is the ideal outcome, allowing it to recover and re-stabilize its root system. As mentioned, each case is different. The age, height, and health of the tree are factors, as is its root system—the size and depth of its primary tap roots, as well as the span of its lateral and oblique roots (which branch outwards underground and keep the tree upright).
If it's practical (in terms of required labor and cost) to save the tree, this will be attempted. It may be possible to stake the tree, using wooden or metal stakes. It can also be beneficial to compact any loosened soil at the base of the tree. A tree that has tilted due to extreme weather could conceivably be excavated and re-implanted at the correct angle. The tree may need concentrated nutrients (in the form of a recommended fertilizer) to recover from its physical trauma. It's likely that different methods will be combined to save the tree.
While saving the tree would be the preferred conclusion to the matter, this may not be possible—or practical. Attempting to salvage the tree will be a futile exercise, and an emergency arborist will clearly inform you if this is the case. In such a situation, the immediate risk posed by the tree is highly-relevant.
A tree that poses a clear and present danger will be immediately removed. This is one of the functions of an emergency arborist—promptly removing a tree so that it's no longer an emergency. The degree of risk is determined by what the tree would damage if it was to fall or shed major branches. This certainly poses an extreme risk to anyone in the immediate vicinity of the tree, which should be avoided until the tree is either stabilized or removed. Any structures or other property (even other trees) that would be damaged if the tree falls will be considered.
The emergency removal of the tree might be unavoidable, so if there's a tree in your yard that came off second best in its battle against the weather, don't hesitate to call an emergency arborist.
Reach out to a local arborist to learn more.