Our upcoming CPD will address the role of Arboricultural Consultants in the planning process to help project managers, architects and planners better understand the requirements with respect to trees and development in light of legislation, planning policy and industry guidelines. Through sharing of past experiences and future challenges, development teams will gain an understanding of how to avoid unnecessary costs delays to development, and how trees can be protected and integrated the overall scheme.
Trees are often seen as constraints to development, while their extensive benefits are difficult to quantify and regularly ignored. With a complex range of issues associated with trees on development sites, having a sound understanding of what to expect through the process is ultimately the best way for developers to avoid the risks. At the same time, being informed of the ways in which trees can add value to the landscape incentivises developers to champion their protection. As with all specialist planning advice, early involvement of arboriculturists can prevent unexpected costs and delays further down the line, while helping to put forward the most appropriate tree strategy.
Trees are protected through a network of policy and legislation. They can be statutorily protected by Tree Preservation Orders or by being within a Conservation Area, and local authorities have a statutory duty to consider the effect of a proposed development on trees when granting planning permission. Increasingly, councils have a specific Tree Policy, which provides another layer of protection. With so many considerations, trees are often viewed as getting in the way of development, but there are solutions that arboricultural consultants can advise on to overcome this.
One way to prevent unexpected objections and to be confident at an early stage that the application is acceptable, is for the project arboriculturist and the council tree officer to liaise from the outset; establishing this relationship is arguably one of the most valuable roles of the arboricultural consultant.
We have been grateful to work with some practical, knowledgeable and helpful tree officers across the country, who have worked with us to find solutions to problems faced throughout the design, construction and post-construction phases. This year we have collaborated with project teams and employed alternative methods, to ensure trees are retained without compromising the end design.
We recommended and oversaw the implementation of air spade investigation in Harrow to identify the true root spread of a mature London plane; this confirmed, as we expected, that the roots deviated from that predicted by the BS 5837: 2012[i], allowing the proposed scheme to go ahead without impacting the tree. Without our practical experience, the developable area would have been reduced, significantly affecting the profitability of the scheme.
We have also advocated the use of cellular confinement systems (CCS) as a method of tree root protection and are pleased to see this is now regularly being utilised to encourage the retention of existing trees. In South Oxhey, the use of CCS has enabled parking bays to be constructed over tree roots, avoiding the impacts of soil compaction and loss of permeability.
When there are no alternatives, the removal of trees can sometimes be justified if appropriate mitigation is provided. In some cases, replacement of existing trees may be acceptable if the proposed landscape strategy results in enhanced genetic diversity, species composition, and a more sustainable mix of age classes within the tree population. This approach can help to provide a more resilient tree stock, better able to cope with future threats including pests and diseases and changing climatic conditions. Sharing of information between the project arboriculturist and the landscape architect throughout the design stages is therefore critical to ensure the proposed landscape strategy meets the arboricultural requirements.
Existing and new trees do have to be considered throughout development, and rightly so, as they are valuable assets from which we all benefit. However, their presence or provision does not have to restrict development, and more often than not, there are practical solutions to keep everyone happy.
We would like to share our experience and knowledge with you – this CPD can be undertaken at your place of work, at a time that best suits your team to ensure maximum value. Please contact Naomi Foot on 0203 544 3995 for more information.
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[i] British Standards Institution. (2012). BS 5837: 2012 Trees in Relation to Design, Demolition and Construction-Recommendations. London. British Standards Institution.