Trees Updates


Conker trees saved by blue tits? (Times)

 One of Britain’s most familiar garden visitors, the blue tit, is flying to the defence of the majestic horse chestnut tree, threatened by invasive caterpillars.

 Wildlife experts believe the birds have taken to eating caterpillars of the leaf miner moth that ruin the appearance of trees and can kill saplings.


                      Can this cheeky fellow save our conker trees?

 The moth which originates in Greece, appeared in southern England in 2002, but because of a lack of natural predators, it spread northwards and has now been reported in Scotland.  The moth lays eggs in the veins of the leaves and the caterpillars eat their way out, turning the foliage brown and making conkers fall prematurely.

 The leaves can become so unsightly that some park managers are now shying away from replanting horse chestnuts in favour of other species.

However, Darren Evans, a biologist at Hull University who has been tracking the moths, said blue tits had started to eat their caterpillars.

‘Blue tits are experts at finding any kind of insects on trees and over time they will learn to eat the thing that is plentiful’ Evans said.

 He added that changing weather patterns may be helping the tits by encouraging moths to lay eggs earlier in the year.

 ‘Because of the leaf miners have multiple generations – up to six through one season – the blue tits seem to be turning to them as a more reliable food source,’ he said.

 Moths shrivel conkers (Telegraph)

 Children will have to make do with shrivelled conkers because of a moth infestation.

 Horse chestnut trees are being infected by leaf miner moths.  The larvae damages the foliage causing fewer and weaker flowers in turn leading to fewer smaller and weaker conkers than normal.

 A spokesman for the Woodland Trust said the moth was a ‘real and growing problem’ that posed ‘a serious threat to the survival of future generations of trees’.

Tree fungus shakes reign of London plane trees (Times)

 The London plane, the tree that graces many of the most famous streets and squares in Britain’s cities, is under threat from a disease.

 Massaria, a fungus that causes branches to dry out and splinter, has been detected in half of the 3,400 mature plane trees in London’s royal parks.  A further study in Islington, north London, found that one in 20 has the disease.

Arborists, who will now carry out further studies, fear that the pruning required to combat the fungus will radically alter some of the nation’s best-known landscapes.

The London plane was first introduced to Britain in the mid-17th century but became popular with city planners during the reign of Queen Victoria.  There are at least 350,000 such trees in the capital alone, providing the canopy for sites including Lincoln’s Inn Fields and Berkeley and Russell squares, as well as lining the banks of the Thames and standing outside the houses of parliament.

Prized for their durability, the trees are also prominent in cities including Bristol, Birmingham and Manchester.

Massaria was first confirmed in a tree in Highbury Fields in north London in March.  Experts suspect that a symbiotic relationship between the fungus and the tree has been unbalanced by a gradual drying of soil in recent years.

Of most concern is the risk of injury or death if branches, which can be seriously weakened by massaria in as little as three months, fall from the trees.  No injuries have yet been reported.

‘The fear with this disease is that we are going to have large branches falling out of plane trees quite regularly’ explained Jake Tibbetts, vice chairman of the London Tree Officers’ Association.

‘These trees are very strong and hardy, but now suddenly we have a fungal pathogen that could lead to them having to be pruned and the loss of some of our more spectacular landscape trees’.

Neville Fay, who sits on a working party investigating the disease, said one theory was that a  lack of moisture in the ground had changed the way in which massaria helped the London plane to ‘self prune’.  Instead, the fungus was now attacking the tree’s main branches.

‘It appears to be an indication of negative water retention – that is, drought stress’, he said.  ‘The trees are telling us something about the conditions in which they are growing’.

Tree officers are anxious that safety concerns do not lead to drastic and unnecessary action.‘The nightmare scenario is that through overreaction these trees are irrationally felled or rendered non-functioning’ said Fay.