As we continue to review how HS2 is influencing best practice in the built environment sector, we look at the importance of protecting the beauty and sustainability of landscapes during construction works:
HS2, the UK’s second high speed railway, is now well underway, promising both economic and environmental benefits.
As well as reducing travel times, relieving congestion and linking key cities, its bosses say it will benefit the environment too: “delivering miles of ecological and landscape investments”.
Given the economic and national interest in this publicly funded project, fulfilling this commitment is vital.
HS2’s construction must adhere to strict environmental protection regulations, bound by its own Environmental Minimum Requirements (EMRs) alongside the legislative requirements of the EA.
The project has a number of controls in place to protect the beauty, integrity and sustainability of landscapes. Both rural and urban areas must be protected from the negative impacts of construction works, including designations of landscaped areas, heritage assets, parks, open spaces and small green spaces alongside or surrounding the 340+ miles of tracks.
Perhaps the most visible demonstrator of successful adherence will be through the preservation or planting of trees along the routes.
What is tree root protection?
Tree root protection measures benefit tree roots and surrounding soils to preserve and sustain trees’ growth.
When delivered effectively, measures prevent compaction of soil or damage to soil structure from traffic moving over the ground surrounding tree roots. They also ensure water and air continue to reach roots, allowing trees to flourish. One solution is for geocells to be installed to absorb and dissipate heavy loads, preserving soil structure and integrity and protecting roots from damage or starvation. If these measures are overlooked, trees can be starved and begin to decay or die.
Protecting trees delivers environmental and aesthetic benefits while also ensuring adherence to regulations.
Delivering tree root protection is applicable for developers working on a broad range of construction and infrastructure projects. Protective measures fall into five categories:
Carry out a survey
Surveys will identify existing trees and vegetation within a construction site, to inform on what is to be retained and what can be removed. Identifying specific locations will also prevent excavation works reaching tree root zones, which can damage the roots and impact trees’ health and longevity.
Seek advice from specialists
Ecological specialists, such as an arboricultural consultant, can advise on implementation of environmental protection methods. Guidance could cover how to sympathetically undertake vegetation clearance, safely deliver tree works or effectively create new wildlife habitats.
Install protective measures
A number of protective methods are available, dependent on the requirements, type, location or length of a project. Where trees must not be disturbed protective fencing can set boundaries, protecting tree canopies to prevent damage to tree branches and avoid obstructions along access routes. Where trees cannot be avoided, geocells can be installed to preserve soils and protect roots (as above).
Existing or new areas of planting or vegetation must be protected from the elements, ongoing construction works or long-term passing traffic or footfall. In some cases, protecting the landscape or its features can require installation of access routes or haul roads, to reduce disturbance on live sites or support the reinstatement of areas on completion of works. Durable access routes, which absorb and dissipate heavy loads from construction vehicles, will reduce the risk of irreversible damage to soils.
Where reinstating areas is required, the correct removal, storage and transplanting of vegetation – such as stockpiling to preserve soil and prevent compaction – will also support on-time project delivery in the final stages of works.
Figure 1 – Installation of geocell for tree root protection
Understand and adhere to regulations
Protecting trees from construction works is often written into planning approvals for new developments, to comply with BS 5837. This rules that trees on or close to a development must be considered during the planning process and can guide on areas to be left undisturbed. Trees which are to be reduced or removed must be treated in accordance with BS 3998.
It is vital that all contractors on-site understand and adhere to the measures so issuing guidance for working within protection zones is recommended.
Monitor the effectiveness of measures
As with any environmental protection measures, continually monitoring their effectiveness and adapting them accordingly is essential.
As well as ensuring tree root protection, implementing these measures will also futureproof some elements of projects. Not only can construction projects risk damaging trees, but trees can pose a threat to completed construction works. Tree roots able to break through tarmac, for example, could create costly repair or remedial works and reputational damage to contractors.
These requirements and measures are not exclusive to HS2 and can be applied on a wide range of project types to ensure sympathetic, considerate construction. Understanding the relevant regulations and control measures to adhere to these will be advantageous to a wide range of contractors and project types.