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The LTOA - Caring for the Capital's Trees

Welcome to the LTOA website. The London Tree Officers Association (LTOA) constitutes the professional & technical voice for London's trees & woodlands. Its aim is to enhance the management of the Capital's trees. We hope that you find the LTOA website both interesting & informative. If you have any questions, comments or suggestions, please do not hesitate to contact us.


London Tree Officers Association seminar 15 December 2015


1.15pm         Welcome from LTOA Chair and a word from our sponsor Gristwood and Toms

1.25pm         Gianmichele Cirulli, Argronomist, Green Space and Tree Heritage Department, Turin Municipality, Italy. “Plane Wilt in Turin: history and strategies around an endemic disease”

2.25pm         Questions

2.55pm         Afternoon tea with scones and cakes

3.25am         Iben Margrete Thomsen, Senior Advisor, Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark. “Urban ash dieback – the Copenhagen experience. What are the implications for future management of ash in London?”

4.25pm         Questions

4.55pm         Finish and down to local pub, the Skinners Arms, Judd Street for LTOA Christmas drinks. We have the section at the back of the pub reserved.

Thank you to Scott Farens of City Suburban for sponsoring the travel and accommodation cost for our European speakers and to LB Camden for hosting the meeting also to Gristwood and Toms for providing the refreshments.

This seminar is for members only.


LTOA Seminar for LTOA members - Thursday 5 November 2015


09:30am - Tea and coffee

10:00am - Welcome from LTOA chair and Executive Officer

10:10am - Sponsors of refreshments GreenBlue Urban

10:20am - David Archer Associates- new member introduction

10:25am - Southern Ecological Solutions SES - new member introduction

10:30am - The Big Tree Debate, Brita von Shoenaich, Bradley-Hole Schoenaich Landscape Architects

11:10am - Break

11:25am - From Dust to Dawn. Planting 90 Dawn Redwoods on the industrialised Edgware Road, Andy Tipping, LB Barnet

11:45pm - Growing semi mature trees for successful landscaping projects, James Hillier, Hillier Nurseries

12:00pm - Large growing species for urban situations, Tom Wilson, Barcham Trees

12:15pm - Felling licence exemptions, Andy Glover, Forestry Commission

12:30pm - Questions

13:00pm - Lunch sponsored by GreenBlue Urban


Thanks and notes

Thank you to Clare Pappalardo at LB Haringey for arranging the venue and GreenBlue Urban for the refreshments.


Ash Dieback

Ash Dieback

On 21st September I attended a presentation organized by the FC at Bedgebury Pinetum from Iben Margrete Thomsen from University of Copenhagen titled “Ash Dieback: a forest threat with limited impact in urban areas and the open landscape.”

One of the most informative presentations on Ash Dieback I have been to. It was a presentation of 2 halves, the first concentrated on plantations and woodlands and the Foresters view point.

There is no doubt Chalara is bad news for foresters; it leaves trees open to secondary infection from things such as honey fungus, stops incremental growth in its tracks and quickly reduces the timber value so that it useless for all except fire wood. Even worse, the natural regeneration and young plantings die rapidly from Chalara infections, and thus the future ash forests are lost.

Iben M. Thompson states:

"Our rules of thumb are that ash below age 10 dies whether in forests or outside, only Chalara needed. Ash up to age 40 dies rapidly in forests (Chalara and Armillaria combined), fairly often in the landscape (depending on site conditions, but still slower and in smaller numbers than in forests) and occasionally in urban environments (already stressed trees). Older ash deteriorate quite fast in forests (older and larger trees slowest), occasionally in landscape and urban settings. This applies once the disease is established and widespread, like I’ve seen in some areas of Kent during my visit. And of course trees with partial resistance will last longest, and after about ten years of severe impact the non-susceptible trees will stand out".

"It’s a disaster in forests but less fatal in towns and the open landscape" reports Iben M. Thomsen. She explains that in towns and cities leaf litter is removed more often than not, dryer conditions means fewer fruiting bodies and suboptimal infection conditions, less risk of basal infection, and no secondary damage agents such as honey fungus or ash bark beetles.

Iben M. Thomsen pointed out that for urban and road side ash trees it is mainly young ash trees which are affected and may die, the older ash trees may deteriorate with occasional death but it can take years for the trees to die. But she also showed us examples of completely unaffected ash trees in Copenhagen.

It is also worth remembering that just because an ash is dying back it may well have nothing to do with Chalara. Iben Margrete Thomsen has investigated many cases of ash dying where the cause was not only linked to Chalara. However, ash trees stressed by other factors will be hit harder by the disease, which may become the final straw, since it kills the most vital parts of the crown.

A good tip was that young ash trees show Chalara dieback symptoms first, if it is not in the young trees it will not be in the old either, so inspect the younger trees first. Another point is that the dieback fluctuates, so trees may look sick one year and healthy next year when new shoots have filled out the crown.

A strong message from the presentation is don't fell to soon.

"Preserve ash trees in cities and along roads and in the landscape for as long as possible, keeping safety in mind."

It is worthwhile pruning out dead branches rather than felling and only remove trees when the tree is either dead, dangerous (eg due to honey fungus in the roots) or no longer of value in the landscape.

So what of the future for ash, she encourages using resilient species such as F. ornus and F. americana. Hopefully, non-susceptible clones of F. excelsior will become available in the future.

For me what I took away is that it is not all doom and gloom as was reported a couple of years ago in the popular press. Not all our ash trees are going to die, we should not panic and should manage and maintain our ash in exactly the same way as we have been doing for years just like any tree, inspect, carry out remedial works and when the time comes which could be many years down the road, remove them when they become hazardous.

Don’t make the mistake as some in Demark did and removed their ash tree too early and are now thinking I wish we had not been so quick to fell.

Iben Margrete Thomsen has kindly provided her presentation that can be found here and I hope that we can organise for her to present at one of our LTOA seminars.


London Tree Officers Association – Position statement OPM 2015


The LTOA and Tree Officers have been involved with the control / eradication of Oak Processionary Moth (OPM) since it was first identified in London in 2006. In 2010 the LTOA published their Guidance Note on OPM.

The LTOA has worked closely with the Forestry Commission (FC) and its partners, engaged with the Advisory Group and maintained its own OPM Working Party. With the current programme review and the possibility of the ending or downgrading of FC control, the LTOA feels it is time to restate its views on the OPM issue.

The LTOA members who wrote this statement are: Richard Edwards (LB Croydon, LTOA Chair), Craig Ruddick (LB Richmond) and Dave Lofthouse (LB Merton, LTOA Executive Committee member).

Click here to download the whole statement


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Members can attend, for free, the the LTOA meetings which are held four times a year and cover a wide range of tree related matters. Click here to find out how to become an associate member


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