The View from Kew
By Kevin Martin
2020-03-16
Kevin Martin is the Tree Manager at RBG, Kew. There, he is responsible for managing the 14,000 trees within the Gardens, working within strict criteria where botanical and historical value are balanced with safety and the challenge of managing an arboretum. In the past year or so, Kevin has found himself also being involved with the management of development works at the Gardens, requiring another skill from him and presenting new challenges.
When I last spoke to Kevin, he was enjoying a breather having signed off the second of the two developments within the site before turning his attention to the winter events and especially the annual Christmas lights. I suggested that this meant he was working five days per week and not seven! He had been involved in creating the displays of illuminations within the branches of two specimen trees, a project requiring some two miles of lighting and taking about two weeks of climbing per tree. The event had been a great success, with all 38 evenings of the programme being sold out.
We spoke shortly after Storm Ciara had hit the UK. How had Kew fared, I wondered? One Birch had fallen over. Was he surprised? The tree had been in decline, with Honey Fungus affecting the roots. I was intrigued that the tree hadn’t been felled, but Keith explained that the winds had reached 55 mph. He didn’t fell trees simply because they were ‘in decline’!
One of the current projects is involving the installation of a new high voltage cable within the Gardens. There is a need for more power within the site. Normally, the cable would be installed by trenching, but at Kew, this would involve the felling of many trees, which is not an option. The solution at Kew has been to use the mole drain system, with the cable being installed under the existing system. An exit pit is being created within the site, albeit outside the Root Protection Areas of the nearest trees. Kevin’s involvement with this project has been less onerous than those of last year. He has provided the BS5837:2012 tree survey work, has pruned trees to provide access for the machinery being used, and supervised where required.
Work has also recently started on the new Arboretum Headquarters. I visited the old facility and share Kevin’s view that it was ready to be updated. There are no trees within the compound of this development, the only issues being the access to the site, where again Kevin has guided.
I am keen to find out more about the work that took so much of Kevin’s time in 2018 and 2019, when the Pavilion was being re-built and a new Children’s Garden was created. For the latter, challenges including the construction of a network of footpaths, which impacted on the Root Protection Areas of some 66 trees. Naturally, a no-dig construction method was needed, using cellular confinement and flexible pavements which have the added benefit of being permeable.
A new viewing platform, creating a circular walk around a significant oak tree, also presented challenges. The footpath was raised on a series of poles, and Kevin used root radar to establish where to place the poles, also using trial pits dug with an air spade to plot the positions. All of the work was supervised by Kevin, who noted how accurate the Root Radar was.
One of the challenges that Kevin faced was getting the contractors undertaking the construction work on side. He prepared a talk and designed a poster explaining the importance of the trees. He also held weekly meetings with the contractors, which was always recorded, and any issues actioned in the Arboricultural Supervisory Document. If the items remained outstanding, they would be taken to the Project Manager for action. With the Children’s Garden, the process progressed smoothly, aided by the same Project Manager being involved throughout.
For the Pavilion, matters were less straight forward. Kevin recalls one digger driver who arrived one morning, having been fully briefed on the correct procedures, then removed the protective fencing in one place, and proceeded to stack soil again a tree, hitting the tree and branches with the digger as he did this. Kevin intervened, informing the driver that this wasn’t acceptable. The driver took a different view, and so Kevin closed the works and the driver did not return.
Kevin is the first to highlight that the arrangements at Kew have been very unusual. He is the client and the consultant, and the local authority stipulates that arboricultural involvement is of this level. He suggests that the planning process should give more power to the Arboricultural consultant. It is hard work doing tree protection properly. For the Pavilion alone, protecting the Root Protection Areas for lorry access contributed nearly £100,000 to the overall £5 million cost.
As our conversation progresses, we share more typical experiences of the Arboricultural Consultant. Kevin observes that it seems some planning requests are unnecessary, and these tend to be found more frequently on smaller sites. How often, with larger scale developments, is tree loss permitted, yet smaller domestic settings are expected to implement significant measures. For one site, where the addition of a single ground floor room required the demolition of a retaining wall, which happened to be in the Root Protection Area of the neighbour tree, but with a difference in ground level of 1.5 metres, his solution was to supervise dismantling, brick by brick. No roots were encountered.
For another site, a large adjacent site was approved with few issues, whereas the erection of a bungalow in a secluded setting involving a single tree needed a full tree report including landscaping scheme. We agree that evidence suggests the planners, and the tree officers, are choosing the wrong battles, and many, good trees are being lost. It is easy to criticise, but we agreed that it does seem rules are applied more thoroughly with smaller projects.
One of the key projects that Kevin is presently dealing with is guidance on climbers using two ropes when climbing. I am keen to hear more. Two rope climbing was introduced by the HSE to reduce accidents among climbers. It has proved to be controversial. Previously, the climber used to focus on working with either a moving or a static rope, but now both are used together. As a manager, Kevin has shared before that he could see the benefits, but also appreciate the frustrations for the climber, especially those working commercially against time pressures. This is an area I am less familiar with, but Kevin is a keen advocate of the benefits of experience rather than simply acquiring qualifications and credentials.
He wonders whether it might be better, rather than a climber collecting their ‘tickets’, having a progression system in place. If, for example, someone began with Aerial Rescue and spent time climbing and gaining experience before progressing to rigging, and then with more experience, to supervising? There is value, he suggests, in providing climbers with more skills. Meanwhile, he is busy working with others on a Tree Climbing Guide which, it is planned, can then be released to the industry later this year. Explaining the benefits of the approach will be central to its implementations, suggests Kevin. He is concerned that climbers, already busy working in a tree, will see the new approach as a hindrance. The next twelve months, he muses, will be interesting, as the scheme is rolled out.
Whether one is a climber or a tree manager, there is little to beat ‘having a feel for trees’, something which Kevin considers can only really be gained through practical experience. He is keen to see a structured route for climbers to progress and learn the technical elements of arboriculture, something I endorse.
Oak Processionary Moth has been a problem at Kew Gardens in recent years, and Kevin has personal experience of its effects on the skin, to the extent that he is not allowed to participate in the treatment work anymore. Controlling this pest has been a major operation at Kew. I recall Dr. Glynn Percival, who was involved with treating it in the early days, arriving for duty one morning in a heavy-duty overall and gloves used for handling asbestos. DEFRA officials initially thought this was over the top, but soon appreciated the severity of the situation.
Only one new nest was identified in 2019, and Kevin will be surveying trees from the end of April through May so that spraying, in mid-May, can be targeted. The hard work is paying off. Kevin certainly works within constraints that many tree managers don’t have. The Gardens have already had more that 2 million visitors in the current year (the Kew visitor year runs to April 2020, and could reach 2.3 million), and with the public attending daily, the spraying needs to be completed before the doors open as it is not practical to close for the day simply to facilitate treatment.
One of the challenges that Kevin faces with this increased footfall is compaction and waterlogging. Whilst he can use mulch and create fenced areas for some trees, for those in grassed areas, this approach is not practical. He is pleased that a new decompacting machine has been purchased. This uses a pin to force air into the soil, creating a small pit. The pit is then back-filled with biochar, which enhances drought resilience. Kevin will be monitoring results with considerable interest.
How has the weather of the past six months affected the trees at Kew? The dry conditions of the summer caused stress, not aided by compaction. The autumn rain came at a time when it wasn’t really needed, leading to an autumn flush of growth. The absence of winter frosts has led to the trees already budding. This and daffodils already in bloom indicates that spring has arrived six weeks early. A late frost would be very damaging.
At times, it feels like Kew is a centre for pioneering work. Kevin hopes to write up the results of mulch trials and the effect of the decompacting machine. For all of the challenges, the future at Kew seems exciting, and in good hands.
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