Tree Safety

Tree Safety Management Plan (2012) and future Tree Risk Management Plan (2024)

The current Tree Safety Management Plan (TSMP) published as part of the Nottingham Urban Forest Strategy (2012, NCC) defines the current tree safety management processes for trees maintained by Tree Services, Resident Services. The main features of this plan are:

1. Trees will be inspected to a regime, of 1-5 years, appropriate to the type of site (assessed by use or occupancy) of where they are situated. Trees on negligible-use sites will only be inspected reactively.  
2. As part of a tree inspection an individual tree risk assessment is made that defines i) the size or impact of the failure of a tree part (the hazard); and ii) the likelihood of a hazard being realised.  
3. A numerical risk rating is generated from a calculation based on i) the target-use of the site; ii) the size or impact of the failure of a tree part (the hazard); and iii) the likelihood of a hazard being realised. This calculation is based on a THREATS type system of tree risk assessment.
4. Risk ratings are banded, so that individual trees are assigned target deadlines (priorities) for completing risk-reducing works. Trees with deemed intolerable risks are proposed as batches of works with timescales/urgency based on the level of risks they present. 

The revised Tree Risk Management Plan (TRMP) has been assessed, and the following improvements have been proposed to increase the effectiveness of the system used and reduce unnecessary inspections where possible.

1. All NCC portfolios will be assessed for un-surveyed trees using the National Tree Map data. These trees will be incorporated into future inspection schedules.
2. The target-use (of the area that a failing tree may affect) of all NCC land will be defined by a process of GIS ‘buffering’ from plotted use-features. These use-features will be either area, line or point features (paths, drives, entrances, picnic benches, playgrounds, woodlands etc.) and will be plotted with premises managers based on site knowledge using GIS tools.
3. The target-use plans of a site will be used to categorise individual trees with a prioritised re-inspection interval of between 1-5 years. Other less used parts of a site may be given a ‘negligible’ target-use and inspections will be reactive-only in these areas.
4. The overall effect of this change, will often be to relatively lower the reinspection interval for large areas of a site and reduce inspection needs.
   For example, a park that currently that has a current, overall target-use ‘moderate’ rating (creating a three-year reinspection interval throughout the park), could, following the changes above, have higher target-use areas identified, and other large areas (considering Wollaton etc.) judged as a ‘low’ target-use rating and receive a decreased five-year reinspection interval. In addition, negligible target-use areas of a site will be defined and removed from the inspection schedule.
5. The TRMP will include a council-wide high wind policy to guide the management of sites with trees, before, during, and after high winds.

Alongside the TRMP, tree works will be prioritised to

• Meet the requirements of the Highways Act to prevent encroachment.
• Reduce the financial and reputational risks from actionable nuisances.

Zonal rating map - Click to view