Commissioning a tree survey: define the question first
‘Is the tree healthy?’ and ‘Can we build near its roots?’ are different commissions. A useful report answers a specific question and explains how the specialist reached the assessment.
Purpose and intended use define the scope
An inspection can record present condition and visible abnormalities. A detailed report supports a decision about retention, damage or planned work nearby. Merely measuring height and location is not a safety assessment.
Say who needs the result: you, a property manager, insurer or authority. Check content and qualification requirements before commissioning. A privately commissioned report does not become an official expert report simply because of its title.
Not every assessment needs measuring equipment
Work often starts with a professional visual inspection of the crown, trunk, root flares and site. This may support recommendations or identify a need for further investigation. A photograph alone cannot show every relevant feature.
Sonic tomography, resistance drilling or a pulling test may be appropriate for particular questions. They investigate different aspects; none is automatically needed for every tree. Ask for the reason and cost of additional investigation before commissioning it.
Arrange assessment early in building projects
A trench, new access route or compacted ground may affect a tree even when its trunk stands outside the building site. State the location, proposed interventions and project stage. Existing plans can help the later assessment.
Commission the assessment before finalising construction. Recommendations may concern protection areas, revised work or specialist supervision. A one-off report and ongoing site supervision are separate services.
How much does a tree survey cost?
One Swiss consultant publishes CHF 135 per hour, excluding travel, any equipment and materials, and VAT. This individual rate is neither a total nor a market average. Both site attendance and reporting time affect the calculation.
Compare quotes for the same question and agreed documentation. A short inspection record is not equivalent to a detailed damage report. Additional tests, samples and meetings should be identifiable and agreed in advance.
| Item | What to check |
|---|---|
| Trees | Number, locations and existing records |
| Visit | Travel, access and examination scope |
| Diagnostics | Which additional test answers which question? |
| Report | Findings, reasoning, photographs and recommendations included? |
| Follow-up | Queries, additions and reinspection included? |
What a useful result should explain
You should be able to identify which trees were examined, when, using which methods, the findings and the limits of the examination. Recommendations should be specific about action, urgency and suggested follow-up.
An assessment now is not a promise that a living tree will remain unchanged. Ask which new events should trigger another inspection. For larger populations, plans or individual identification help ensure recommendations are applied to the correct tree.
Prepare records without trying to diagnose
Existing reports, damage photographs and plans may avoid duplicated work. Say when visible changes were noticed. The request does not require fungal identification, drilling or a home load test.
For disputes or damage, factual and understandable documentation is particularly important. Clarify the independence of the assessment too. Subsequent pruning or felling should be a separate, explicitly agreed commission.
Frequently asked questions
Is a green tree automatically stable?
No. Vitality, stability and resistance to breakage are different questions. A specialist assesses the features relevant to the commission.
Do I need to order tomography?
No. Describe the question to resolve. The specialist determines whether visual inspection is enough or a particular additional test is justified.
Can I have several trees assessed?
Yes. Give a count or provisional scope. For larger populations, agree identification, the output format and possible reuse of existing records.
Does the survey include recommended work?
Only if it is explicitly commissioned in addition. Examination, reporting and later maintenance are separate services.
