Trees in the City - 26th April 2014 - Conference Report

The Brockley Society Tree Committee are delighted to report a little more fully about the presentations given at our hugely successful conference last month. 

Wake up and smell the pollution

Lewisham Mayor Sir Steve Bullock opened the conference by raising the issue of rising city pollution and the need for more trees to make the urban environment sustainable. He kindly stayed with us for the opening presentation by Tom Armour. 

Can’t stand the heat? 

Tom Armour, founder and Director of Arup’s Landscape Architecture business gave a fascinating talk about the benefit of urban trees. He showed how the greenest areas in London can be as much as 8 degrees C cooler than the most built up areas. The cooling effect of (large) tree canopies has been well known for some time, but never shown so graphically for the lay audience.

Bring back the birch

Professor Barbara Maher (whose work we reported on here back in October 2013) gave a video-conference talk from Lancaster and presented her celebrated research showing that silver birch trees reduce pollution even at a very local level. Many of us in the audience were struck with the insidious way in which these tiny 'particulates' (from car and lorry diesel fumes) get deep into the lungs. We were surprised at how small the birch trees were in the research experiment (so we don't need to wait until they are mature to reap the benefits!). 

The Silver Birch tree screen in situ for Barbara Maher's important research
Photo courtesy of Barbara Maher

Dwindling resources

A panel discussion which included Lewisham Planning and Lewisham GreenScene highlighted the problem of dwindling council funding and increased pressure to fell trees from insurance companies. Keith Sacre, from Barcham Tree Nurseries, also on this panel, had great ideas on what species to replace lost trees with, and he very generously brought a pile of beautiful hardback catalogues which he donated to the conference attendees (he is happy to supply more if people ask).

Logging the blog

Eamonn, one of our tree committee, demonstrated this blog (which has now passed 10,700 page hits since it started in October 2012!). 

Chainsaw Massacre

Cllr Darren Johnson introduced the afternoon discussing the findings of his (2007) report (blogged here in 2012). Again the issue of contentious pressure from insurance companies to fell trees was raised.

Living legacy

Rachel Mooney from Friends of Hilly Fields gave a fascinating talk showing some amazing photos of Edwardian Brockley with saplings where there are now mature trees on Hilly Fields. It was a sobering reminder that we need to continue planting to protect and extend this legacy.

Photos courtesy of FoHF and Phil Hall

Bearing Fruit

Lewis McNeill from the London Orchard Project in Hackney  showed us pictures of some innovative planting – tiny gardens on street corners or at bus stops tended by local people; apricot trees in Hackney bearing fruit, and fruit trees growing up vertical end-of-terrace walls!  The involvement of local people is crucial for getting these projects off the ground, and then for sustaining them, as they do, by active monitoring, mulching and watering these vulnerable new plantings. He went on to emphasise how young people start to feel protective of "their" trees once they have invested their time and effort in planting them! 

Greening your street

Anthony, one of our tree committee, explained how our scheme developed with Lewisham Council can help Brockley residents fund new trees for their streets.

No blame no claim

Our afternoon panel* discussed practical issues about managing our existing trees and trees being wrongly blamed for subsidence. This is a serious threat to our tree stock and at the moment legal protection for trees is weak. This is something we intend to campaign on at a London-wide and national level. At the end of the panel discussion Angelo very generously offered to donate funds to purchase a new street tree for us, for which we are very grateful. 

Pump up the volume

Our last speaker was Andrew Wilson, Director of Garden Design Studies at the London College of Garden Design. He reminded us that trees are 'greenery in 3D' and showed great examples of small gardens where dwarf trees add a large volume of greenery/canopy without compromising space (many of our new plantings are very immature trees and will provide little in terms of canopy cover for many years - and as Tom Arbour showed us so graphically in the opening presentation, mature canopy is what provides the cooling effect).  

* Angelo Morgan from TreesUK Tree Surgeons, John Bellman, a consulting Civil and Structural engineer and Richard Evans, Vice Chair of the London Tree Officers Association

Again, our grateful thanks to all who presented, and to all who made the conference such a success (not least the excellent support given us by the staff of LeSoCo on the day, and in the run up to the conference). 

All of us on the Brockley Society Tree Committee 

Chainsaw Massacre - The Prequel

In May 2007 The London Assembly Environment Committee published their report 'Chainsaw Massacre - A Review of London's Street Trees'. Our own Green Party Councillor for Brockley Ward Darren Johnson was Chair of this committee. 

To see the report in PDF format go here

At the point of publication this was clearly a comprehensive assessment of the state of London's street trees. Taken as a whole, there had been a net gain of 8,000 trees planted across the Capital in the five years before publication (this was data collected by the London Tree Officers Association - LTOA). 

However, the picture is very patchy. 

In the same period, there had been a net loss of street trees in a third of London boroughs. Harrow, for example, lost 5,000 street trees and only replanted about 2,000, a more than 16% loss. Croydon lost 2,600 and was only able to replant 600 of the trees removed (a net loss of 6%).

The good news comes from the remaining two thirds of London boroughs who replanted more trees than they removed. Redbridge planted 4,850 trees and removed about 2,880. Barnet managed to plant over 3,700 trees having removed just over 2,400. Richmond planted 2,500 trees and removed 1,400. lambeth planted over 1,300 trees and removed just under 500 and Southwark planted over 1,750 and removed about 250. Lewisham reported 808 removals and 839 planted in the same period (a net gain of 0.26%). 

Some of the most disturbing reading is about the activity of the insurance companies whose instructions to fell trees are responsible for a considerable amount of tree destruction across the Capital. In Section 3 read this: 

3.5 The Mayor's London Tree and Woodland Framework document states that the perceived threat of subsidence [due to root incursion] is much greater than the actual threat and it is estimated that less than 1% of the total tree population has actually caused damage to properties. This has led to the London Tree and Woodland Framework Manager (LTWF Manager) naturally concluding that insurance industry subsidence statistics should be challenged.  

To support a great deal of constructive work being done by the LTOA to mitigate the effects of tree damage to property, one of the key recommendations coming out of the report states that: 

Recommendation 2

The insurance industry needs to provide evidence of better quality investigations that comply with nationally recognised guidance ensuring that accurate reliable tests are used in their investigation of tree root related subsidence claims

And in respect of the trees we are losing: 

Recommendation 3

London Boroughs should do everything within their power to prevent the loss of street trees, but where the removal of a tree is unavoidable, replacement trees should be planted in suitable and agreed locations within the same vicinity

There is much to recommend a thorough reading of this report. It is certainly a significant resource for us as we work to protect and enhance our local street tree stock.