Quick answer: Tree Risk Assessment — Trees on this coast live with fog, salt, wind and thin soil, and the work that keeps them healthy is decided by those conditions rather than by a calendar written inland. Structure, clearance and the root zone are what a tree here needs looked at, and small work done early is what keeps a tree out of the emergency list.
Field note. What we see on this coast is that the trees people worry about are usually not the ones in trouble: the pine with a clean crown and a lean that predates the house is often sounder than the tidy tree that has been quietly drowning in its own root zone.
On the other hand, there is no schedule that suits every tree — the same species on two sides of one street can need opposite care, which is why we look before we recommend.
The phrase “risk assessment” gets used for everything from a five-minute look to a two-hour measurement. The difference is not effort, it is whether the output can be acted on and defended.
What a risk assessment is not
It is not a pruning quote with a paragraph on top. It is not a statement that a tree is “safe” — no tree is, and a document that says so is not an assessment. And it is not a prediction, because the question is not when a tree will fail but what would happen if it did.
The three components
The defect. What is wrong, where, and how large. A cavity with a measured opening, a union with included bark, a lean that has changed, a root plate that has lifted. A defect that cannot be described in those terms is a suspicion, not a finding.
The likelihood of failure. Graded, usually on a scale from improbable to imminent. The grade comes from the defect’s severity and the load it carries, and the load on this coast includes a wind regime that is not occasional.
The target. What the tree can reach, how often it is there, and how exposed it is. A path used daily and a shed used twice a year are different targets, and the same tree over each of them is a different risk.
What the grades mean in practice
A tree with a defect, a moderate likelihood of failure, and a frequently occupied target is a tree that needs action. The same defect over an unoccupied corner is a tree that needs monitoring.
That is the whole value of the exercise: it separates the trees that need work from the trees that need watching, and it does it on stated criteria rather than on how alarming the tree looked.
What the report should answer
What the defect is. What would happen if the tree failed. Who or what is at risk. What the options are, with the residual risk after each — removal, reduction, cable, target relocation, or monitoring.
And, at the end, a recommendation with a timeframe. “Reduce the two longest limbs on the windward side within twelve months and re-inspect in two years” is an assessment. “Recommend removal” without saying what the alternative was is a quote.
What should not appear
Absolute assurances. Predictions of a specific failure date. A recommendation for removal that does not state the residual risk of the alternatives. And a document that does not record the date, the conditions and what was actually inspected — because the value of the report is that it is a record.
Levels of assessment
A walk-by or drive-by look is a screening, and it is useful for a property with many trees. A basic assessment is a ground-level inspection of each tree with the three components recorded. An advanced assessment involves measurements — a resistance drill, a sounding, sometimes an excavation at the roots — and it is what a marginal case needs.
Most trees need the basic level. The advanced level is for the tree that is significant, close to something, and genuinely ambiguous — which is a small number.
What the owner does with it
Act on the recommendation or record the decision not to. Either is defensible. What is not defensible is having a report that recommended work and having done nothing, because that establishes knowledge, which is the insurance point.