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ROYAL PARKS BOARD/MARCH 2013/ AGENDA ITEM 8
The Royal Parks Board
Date of Meeting: 7 March 2013
Subject: Tree Health Management
Back ground:
This presentation is an abridged version of one presented to the Park Managers meeting on 27th
February.
Its intention is to highlight the current and possible future diseases which are affecting The Royal
Parks.
Covering information on Massaria:
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Massaria was first discovered as a tree health and public risk problem in the UK by TRP
arboricultural staff in 2008.
We produced a paper on issues and identification of Massaria which was published on the
Arboricultural Association and London Tree Officers Association’s websites.
A Massaria inspectors post has been created to survey the 2560 Plane trees for the disease
due to the high risk from falling branches.
Over £200,000 has been spent to date on Massaria affected branch removal.
TRP are closely involved in an external consultants study into the causes and possible
remedial actions.
Covering information on Bacterial Canker of Horse Chestnut:
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These trees are a key component in all our Parks with key plantings on Blackheath Avenue
in Greenwich Park, The Quarters in Kensington Gardens and Chestnut Avenue in Bushy.
Approximately 70% of the Horse Chestnuts and 95% of Red Horse Chestnuts in the parks
are currently infected.
It has been present in TRP for over a decade; mature trees are now becoming hazards due
to secondary decays.
Approximately £35,000 a year spent on remedial works and felling.
Covering information on Oak Processionary Moth (OPM):
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A breeding population was first found in Richmond Park in 2009 and in Bushy Park in 2010.
A single nest was found in Brompton Cemetery in 2012.
The Forestry Commission is the statutory body charged with its management under the
Plant Health Act 1967. This is enforced by the serving of plant health orders to landowners
of infested sites. This stipulates the treatment of the infestation by the date on the notice.
The statutory requirements of Management of OPM in Richmond Park is linked to its status
as a SSSI and NNR and the statutory obligation to undertake management methods with as
little impact on the biodiversity in the park as possible.
A team of seventy volunteers has been used to survey for the nests.
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ROYAL PARKS BOARD/MARCH 2013/ AGENDA ITEM 8
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£170,000 spent in 2012 on spraying and nest removal.
Covering information on Acute Oak Decline (AOD)
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First found on TRP Oaks in 2010 and Forest Research has included them as part of their
AOD study for the last three years.
Ongoing research shows two causal agents are likely to be involved – a genus of bacteria
previously unknown to science and the Buprestid beetle, Agrilus biguttatus. Active research is
underway to clarify the relationship between the two.
Remedial Tree work costs currently £25,000 per annum for Richmond and Bushy.
A joint project with Treework Environmental Practice and Laverstoke Park Laboratories has
been trialling mitigation treatments.
Covering information on Ink Stain disease of Sweet Chestnut
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Greenwich Park has 698 Sweet Chestnut in its landscape, including very valuable veterans
from the original c 1660 Bormann plantings.
Canopy dieback symptoms first noticed on Greenwich Sweet Chestnuts in 2011 but
sufficient symptoms to implicate a Phytophthora were not evident till 2012.
Forest Research is to confirm disease responsible in April whilst the fungi are active.
A full canopy health survey of Castanea in Greenwich will be carried out in summer 2013.
Covering information on Ash Dieback
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A fungal pathogen which infects the leaves then aggressively attacks tissue down the petiole
into the twigs or branch. Once there it forms cankers which eventually ring girdle and kill
the affected part above the canker.
Spreads via spores on the wind or through transportation on vehicles or footwear.
Covering information on Asian and Citrus Longhorn Beetles:
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Devastating wood boring beetles which have a wide host range.
ALB and CLB are notifiable species and their presence should be reported to the Forestry
Commission and FERA immediately. It is likely that any infected tree will be felled and a
buffer zone of 2km established.
One outbreak in Maidstone, Kent from contaminated packaging imported from China, which
has so far been contained.
Covering information on Sweet Chestnut Blight:
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Sweet Chestnut Blight is a fungal infection which attacks the bark and is usually fatal.
It devastated Chestnut forests in the eastern USA during the first half of the 20th century,
killing an estimated 3.5 billion trees after it was accidentally introduced there from Asia.
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ROYAL PARKS BOARD/MARCH 2013/ AGENDA ITEM 8
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Not currently a problem in the UK but there was a recent outbreak from imported French
trees planted in the Midlands which has been contained.
Covering information on Canker Stain of Plane:
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Canker Stain of Plane is a wilt pathogen closely related to Dutch Elm disease which causes
pronounced xylem staining, severe wilting and tree mortality on all species of Plane tree.
Trees once infected must be felled as there are no effective control measures and to
prevent cross infection.
This disease is a particular problem where there are interconnected root systems such as
avenues; the disease can spread very rapidly between trees along the root grafts. This has
been demonstrated on The Canal du Midi where over 40,000 Planes are being felled along
150 mile stretch.
If introduced to The Royal Parks Canker Stain of Plane would alter the landscape of the
central parks irrevocably.
Recommendations for management
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Increase of inspection for Ash Dieback and OPM in the Central Parks.
Create a program of soil mitigation across all parks to increase tree vitality in prioritised
areas.
Review grass mowing and leaf collection regimes in the grounds maintenance contract
review.
Continue establishing and using industry best practice when dealing with tree health
problems.
Increase Bio-security controls on the import of trees and woody shrubs into all The Royal
Parks (already actioned).
Ian Rodger
28 February 2013
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