Infection is via spores from fruit bodies on leaf litter. Spore production in fruit bodies occurs on infected fallen leaves and shoot material in the growing season after infection, trees are likely to need a high dose of spores to become infected. Chalara fraxinia causes infection from June to October, mainly in July to August. Moist conditions favour production of the fruiting bodies.

How does Ash dieback Chalara fraxinia spread?

Spores are produced on Chalara fruit bodies formed on fallen leaves and shoots the year after becoming infected. Natural spread is by wind blown spores from these fruit bodies. Wind blown spores may be dispersed up to 12-18 miles. Longer distance infection occurs via infected plants or potentially via wood products.  There is a low probability of dispersal on clothing and footwear or via animals and birds. There is a lower risk of Chalara fraxinia spreading over the winter as there is now a ban on ash imports into the UK, restrictions on plant movements through Statutory Plant health notices and as spore production is not expected to resume until June 2013

Trees cannot recover from infection but larger trees can survive infection for a considerable length of time and some may not die.

For an informative film on Chalara fraxinia please follow this link:

http://www.youtube.com/watch?v=8sI7hgFZ-4g&feature=youtu.be

The Forestry Commission has also published a new, improved pictorial guide to the symptoms of Chalara fraxinea infection, at www.forestry.gov.uk/chalara

The latest forestry commission video on identifying ash dieback in spring can be found here:  http://youtu.be/UuU8_e0Vw8Q

For any further info on the disease Chalara Fraxinea please give us a call

Imported trees from the Netherlands are to be destroyed following the discovery of ash dieback disease.

The serious fungal disease ash dieback has hit the UK for the first time after 2,000 imported trees from the Netherlands were sold by mail order from a southern nursery.

Chalara fraxinea pseudo albidus-infected specimens were bought by 90 customers who received a notice to destroy from the Food & Environment Research Agency (FERA) last month.

FERA principal plant health and seeds inspector Derek McCann said the disease is “a serious concern”. It has been in continental Europe for 30 years and causes leaf loss and crown dieback in affected trees and it may lead to tree death. Up to 90 per cent of ash trees on the continent have been affected.

The 1m and 1.5m ashes were supplied by a Dutch trading company but sourced from overseas nurseries that FERA is still trying to identify. The new tree disease is not an EU regulated pest.

McCann said he was confident that all 2,000 specimens would be destroyed. “Because they were sold mail order, we have accurate lists of who bought them. The legal requirement is for destruction. That means taking them out of the ground, chopping up, double-bagging and taking to landfill. Burning could fall foul of Environment Agency regulations.”

He added that plant health inspectors were more aware of the disease and would be on the lookout for it on regular inspections, but would not be making special visits to nurseries.

Ash is not regulated by plant passports but McCann said FERA would do as much as it can to eradicate the pest and ensure the infected batch “will have been destroyed”.

A Forestry Commission risk assessment on the level of threat is said to be imminent and will be published for consultation.

Exotic pest alert

Forest Research has produced a pest alert. See www.forestry.gov.uk/pdf/pest-alert-ash-dieback2012.pdf/dollars FILE/pest-alert-ash-dieback-2012.pdf. Report suspected cases to its Tree Health Diagnostic & Advisory Service (01420 23000/ddas.ah@forestry.gsi.gov.uk). See www.forestry.gov.uk/ashdieback.

An outbreak of the Asian longhorn beetle (ALB), an exotic pest which could have severe consequences for British trees, has been found in Kent, the Food & Environment Research Agency (Fera) has confirmed.

Asian Longhorn beetle

This is the first time an outbreak of this pest has been found in the UK, and FERA says it is being treated “extremely seriously.”

Fera and the Forestry Commission are taking “urgent steps to try to eradicate the outbreak before it has the chance to spread further afield”.

Several larvae of the beetle were found inside a poplar tree during a routine survey by the Forestry Commission at a site in the Paddock Wood area. Scientists from the Commission’s Forest Research agency had been monitoring an area around the site where an adult beetle had been found in 2009, and this is the first evidence of tree infestation. It is thought the beetles originated from wood packaging used to import stone from China at an adjacent industrial site.

The Asian longhorn beetle is not native to the UK, and poses a serious threat to a wide range of broadleaved trees and shrubs such as maple (including sycamore), elm, horse chestnut, willow, poplar, birch and some fruit trees.

Asian longhorn beetles are almost identical in appearance to the citrus longhorn beetle Anoplophora chinensis), another non-indigenous, long-horned beetle that threatens trees in Britain.

Citrus Longhorn Beetle

 
Adult beetles are large (about 20 – 40 mm long) and shiny black with variable white markings. Their antennae are particularly distinctive, being much longer than their bodies (up to twice the body length) and are black with white or light blue bands. The larvae of the beetle feed undetected on the inside of the plant, and can kill it or leave it weakened and susceptible to further pest and disease damage.

The adult beetles scrape away a portion of bark on a host tree to lay their eggs just underneath. The lifecycle from egg to beetle is one to two years in Asia, and possibly longer in the UK.  Beetles emerge from spring onwards and will mate and lay eggs, after which they die. When the larvae hatch, they feed by boring into the upper part of the trunk and branches, which makes them difficult to detect.
Other signs of the beetle’s presence which might be present but less obvious, include piles of sawdust-like droppings at the base of infested trees, scraped bark, and bleeding sap at the site where eggs have been laid.
Not only do the larvae cause structural damage, this damage also leaves the tree susceptible to other pests and diseases. This can eventually lead to the death of the tree. Analysis of climate data by Fera scientists suggests that most of England and Wales and some warmer coastal areas of Scotland are suitable for ALB establishment, but south-east England and the south coast are at the greatest risk.

The most obvious symptoms of ALB damage are the circular adult exit holes, which are about 10 mm in diameter and are generally found in the main trunk and above. The adult beetles usually emerge from these holes between May and October.

Anyone who suspects they have seen an Asian longhorn beetle, or evidence of its presence, should contact the Fera Plant Health Helpline on 0844248 0071 or email planthealth.info@fera.gsi.gov.uk. If possible, the beetle should be caught and placed in a secure container so that an inspector can collect it. The beetles are not harmful to humans, although they should be handled with caution because they can nip the skin.

More-detailed information about ALB can be found on the Forestry Commission’s website at www.forestry.gov.uk/asianlonghornbeetle. A fact sheet is also available here http://www.fera.defra.gov.uk/plants/publications/documents/QIC57.pdf

Starting work on willows

Removing trees above ford

Most of the trees were in residents’ back gardens and some required winching along the river itself to extract the logs. The two teams started at opposite ends of the village and managed to clear an average of ten large trees a day.

Clearing riverbank

Winching trunk out of river

All logs were cut to size for the individual residents and all waste removed from site.  The appearance of a nesting mallard necessitated the creation of a 30m exclusion zone for 3 months for nature to take its course.  We will return in July to clear that section. We completed the first phase of work exactly on time having removed 209 trees and over 75 tonnes of woodchip. This chip has been stockpiled and will be allowed to compost into mulch which will be incorporated back into the re-planting of the village.  The stumps of the trees will be removed by the principal contractor Jackson Civil using excavators and stockpiled.  We will then return in the winter to recycle these stumps to produce mulch for the replanting project.  This will involve the use of a tub grinder. The tub grinder is capable of grinding down the largest stumps including the roots.    Follow this link to see a tub grinder in action.   http://youtu.be/8Jjufewc4m8

Why do trees lose their leaves?

Deciduous trees lose their leaves in autumn, the process takes place over four to six weeks as daylight hours shorten and temperatures decrease. This provokes the tree into the process known as abscission. The tree produces a cork like substance which slowly blocks the veins within the leaf and acts as a coagulant to ensure the tree doesn’t bleed to death once the leaf falls. At the same time the circulation of liquid around the leaf gradually lessens. Just before the leaf falls some useful nutrients are taken from the leaf and stored in the stem for later use. As water supply to the leaves lessens the chlorophyll is unable to keep the leaf green, this leads to the spectacular colours seen in different trees in autumn. Various shades of red,gold, orange and yellow can be seen dependent on the different levels of carotin and xanthophylls present in the leaves. Shade can also determine how well a tree will display its autumn colours.  When the process of abscission is complete the leaves simply  fall from the tree.

Leafy facts

A large oak tree has on average 700,000  leaves, a large apple tree only has 50,000!

Which tree can I plant for autumn colours ?

Small trees/shrubs include:

Amelanchier canadensis (snowy mespilus) white flowers and good autumn colours

Rhus typhina (stag’s horn sumach) large leaves and vivid colours

Medium trees (up to 8m tall)

Parrotia persica (persian ironwood) has red and yellow leaves .

Acer’s offer a great selection for autumn colour from the simple Acer campstre (field maple) which is our only native maple with its stunning gold to our personal favourite , Acer palmatum osakazuki which is a member of the Japanese acer family and shows amazing red and orange tints.

Others which have stunning colours and bark include Acer davidii,Acer forrestii and Acer pensylvanicum.

Larger trees (over 8m)

Prunus sargentii (Sargent’s cherry) has a red autumn colour.

Gingko Biloba (maidenhair tree) is another great tree with its yellow colour.

Taxodium ascendens (river cypress)

Should tree works be avoided during autumn?

Certain tree care practices should be avoided. Pruning should never be carried out during the abscission period. This excludes deadwooding of trees. Tree removals are unaffected as the tree is effectively being killed off.

Once felled the tree was sectioned and split using our 25 tonne log splitter. We produced over 12 cubic metres of firewood.

Trees are anchored into the soil by their roots.  The roots also take up water containing dissolved minerals, which then travels up the tree via special vessels called xylem within the wood of the tree. This upward passage of water and nutrients is caused by 2 phenomena; transpirational pull which is created by the evaporation of water from the surface of leaves which then pulls the sap up the xylem vessels and root pressure which is created by osmosis of water into the roots causing a positive pressure that forces water up the trunk of the tree.  Damage to roots or soil compaction above roots, such as from vehicles or construction traffic can therefore seriously affect the health of a tree.

The leaves of a tree are important in capturing sunlight energy which is converted into sugar by the process of photosynthesis. This chemical
reaction also uses carbon dioxide which is absorbed by the tree from the atmosphere and releases oxygen and so is a very important process to maintain a healthy balance of gases in our surroundings. This also explains how an unprofessional prune of a tree canopy can seriously damage the tree’s health.

 
The sugars that are created by photosynthesis are then transported around the tree in vessels called phloem. The sugars are either used to feed the cells of the tree or either stored for future use. The phloem vessels are found in the innermost layers of the bark, hence a tree will
normally die if a ring of bark is removed right around the tree.

 
During winter when deciduous trees lose their leaves, the tree survives on stored sugars produced earlier in the year.  The process of leaf drop conserves water and helps some trees better survive harsh winter conditions. The most stressful times in the tree’s yearly cycle are when it is coming into leaf and when it is shedding leaves. Pruning operations should not take place during these times.