Posts tagged ‘disease’
May 3, 2011
My 32 mile cycling adventure through London in March with 22 other Ride for Research riders, in aid of raising funds to support research into acute oak decline disease, accumulated a total of £5,500. A cheque was presented recently to scientists from Forest Research.
Russell Ball’s personal account of organising the event and taking part was published recently in the London Tree Officer Association website.
March 16, 2011
The Ride for Research sponsored cycle ride, in aid of research into oak disease, is one week away today.
I’m looking forward to tackling 15 miles of London’s streets with 29 other riders on 23rd March, visiting three schools along the way to plant trees with children. I will be taking lots of photos on the day and write further news after the event, so watch this space.
Thanks to the many people who have given so generously and helped me reach my target of £200. If you are able to help me raise more money to help support this important tree research, please visit my Ride for Research post where you will find instructions on how to donate online.
March 14, 2011
I co-authored a pruning leaflet about eight years ago which has been a popular guide for woodland owners, managers and others who care for trees (see previous post). However, there was a serious omission in the leaflet that has prompted an update: the importance of sterilising tools between trees, and between sites to reduce the risk of spreading infection.
The importance of phytosanitary control is now paramount, with the apparent increase in serious outbreaks of pests and diseases affecting our trees, such as Phytophthora ramorum (Sudden Oak Death) [apologies for incorrectly stating Acute Oak Decline in a former draft]. Knowledge about the impact on disease spread from pruning has existed for over a century: in the USA Waite and Smith (1906) linked fire blight (Erwinia amylovora Burrill) infections in plant nurseries to contaminated pruning tools. More recently Goodman and Hattingh (1988) reported a 66% infection rate in trees pruned with secateurs treated with bacterial spot (Xanthomonas campestris pv. pruni Smith), although interestingly infection rates were only this high during cool and wet conditions. The worst case of infection spread will come from pruning weeping bacterial wounds, e.g. cankers, where extreme care should be taken to clean tools after use – better still, wait until the oozing has dried up before pruning. There is some evidence that even the best cleaning methods are ineffective at removing bacteria from the surfaces of cutting tools (Kleinhempel et al. 1987).
The following action is recommended on sites where there is a biosecurity problem but I would go further suggest that it is good practice to follow these recommendations at all times.
Sterilise pruning tools between use on each tree by wiping with a cloth soaked in industrial methylated spirits (IMS). You should also complete a more thorough sterilisation between sites, by soaking your tools in IMS.
Some suggest using household bleach, perhaps diluted nine parts water to one part bleach. However, be aware that bleach is extremely toxic to plants, will ruin your clothes if splashed or dripped onto them, and it is a corrosive that will also spoil your tools.
After a hard day’s work in the garden or woods, and following disinfecting your tools using IMS as recommended above, rub some vegetable oil over the metal parts to keep your pruning tools in perfect working order.
February 18, 2011
So far I have been promised £170 in sponsorship funding for the Ride for Research event on 23rd March – thank you to everyone who has supported me. Can you help me raise more for oak disease research? Read more
February 15, 2011
Chronic oak decline, acute oak decline, sudden oak death … there is widespread public concern about the health of the nation’s flagship tree species. What’s the difference between these diseases and what causes them?
Chronic oak decline
The deterioration in the condition of an oak tree is often referred to as “oak decline”. It can be caused by a number of abiotic (e.g. drought, wind, soils) or biotic (e.g. pests, diseases, fungus) factors. Chronic oak decline is the slow deterioration of oak trees, usually Pedunculate Oak Quercus robur, visible first in poor foliage condition, followed by death of the finest twigs and ultimately the largest branches over possibly a number of years, or even decades. The tree may die but, in some cases, fully recover. Read more
Acute oak decline (AOD) is a relatively new disease in the UK with an increasing number of reported cases each year, mostly in the English Midlands, with records extending into Wales. The main symptom is extensive bleeding on the tree’s stem (trunk). A dark fluid oozes from splits in the bark, often from 1m above ground level and upwards. It is usually found on mature trees, 50 years or older, and both major oak species (Pedunculate and Sessile) in the UK are affected.
Unlike chronic oak decline, a tree affected by AOD may die quickly, within five years. The exact cause(s) of AOD are not known at present but Forest Research believe that a bacteria may be the likely factor.
If you suspect a case, oak trees with symptoms of extensive bleeding may be reported to the Tree Health Diagnostic and Advisory service.
Sudden oak death
Sudden oak death is caused by Phytophthora ramorum which is a fungus-like pathogen. The name Sudden oak death came from the USA where the pathogen has caused the widespread death of Tanoak (Lithocarpus densiflorus) and some native oak (Quercus) species, especially in coastal California and Oregon. In the UK we are fortunate (touch wood!) that our native oaks appear to be more resistant than their American cousins. In the UK an alternative name ramorum dieback may be more appropriate.
In the UK the majority of ramorum dieback cases have been in plant nurseries, on ornamental plants such as Camellia, Rhododendron and Viburnum. There have also been a number of outbreaks in gardens, parks and woodlands, usually associated with infected Rhododendron ponticum.
Until 2009, infection of trees was relatively rare in the UK. However, in August 2009, the disease was found on Japanese larch (Larix kaempferi), killing large numbers of trees in south west England, and later with several cases in Wales, Northern Ireland and the Republic of Ireland (see map), and more recently Scotland. Symptoms on larch include a discolouration of the needles, turning first purple, then black before falling prematurely. Bleeding cankers may be visible on a tree’s stem and branches. Shoots wilt and ultimately the tree’s crown will dieback, followed by tree death.
February 10, 2011
On 23rd March I am taking part in a sponsored cycle ride in London to raise awareness of acute oak decline, and to raise money to support research. Please sponsor me to support this important work.
I will be one of up to thirty riders following a circular 15 mile cycling tour to visit three London schools in Brent, Camden & Harrow. In each ‘tarmac-blighted’ school two to three trees (large shade species) will be planted. The school children will be involved in the planting which will be used as an opportunity to promote the importance of urban trees.
“Thanks very much to everyone who is taking part in or sponsoring this Ride for Research. It’s an excellent initiative at a time when our trees are under increasing threat – and when public spending cuts are starting to bite. Acute oak decline (AOD) is just one of several serious tree diseases that have appeared in the UK in recent years. AOD is especially worrying, since it is believed to be caused by bacteria – the kind of organisms that have spread so devastatingly amongst our Horse chestnuts, causing a similar disease.”
“This Ride for Research will help to fund research that can underpin improved control of AOD and other threats. It will, I hope, also promote awareness among everyone who can help to reduce threats to our trees. I include officials and politicians with responsibility for quarantine laws governing international trade in nursery stock (a suspected major source of ‘new’ pests and diseases). I also include members of the public in areas where diseases like AOD are found. And, especially, I hope that all those of us who work with trees will follow the current advice for recognising AOD and for preventing the spread of the bacteria via tools, boots and ‘arisings’. ”
Dr David Lonsdale, Tree Safety Consultant, Writer & Lecturer
I am expected to raise a minimum of £200. Please sponsor me to help raise funds for this important work. You can make a donation online here. Please quote : “Ride for Research – Gabriel Hemery” [very important please!]
Ride for Research is being helped by the Red Trust who are handling the fundraising with their CAF account. Your donation will go even further if you use Gift Aid – just tick the box when you donate.
Please quote: Ride for Research – Gabriel Hemery