Press Release - Anglers Recruited In Fight Against Tree Disease

[Guest Elton]

Forestry Commission scientists are appealing to anglers for help in tracking down two diseases threatening alder trees in Scotland.

 

Ten percent of riverside alders in England and Wales are known to be dead or dying from a disease caused by a species of the Phytophthora fungus. Alders in parts of Scotland are also known to be affected by the Phytophthora - and another condition known as "crown dieback", the cause of which is unknown.

 

"However, our knowledge of the extent of these problems in Scotland is still incomplete, and for that reason we want people who are out and about in the countryside this summer to tell us if they think they have come across any cases of Phytophthora disease or dieback," said Dr. Steven Hendry, a pathologist with the Commission's Forest Research agency.

 

"We believe that anglers in particular can be very helpful, because the alder is Scotland's most common waterside tree, and many anglers are also good amateur naturalists with an excellent knowledge of riverside ecology."

 

"Alders help to stabilise riverbanks, thrive in poor soils, and provide food and shelter for water and land animals, so they are very important in the ecology of the Scottish countryside. And although they are often overlooked, they make a significant impact on the landscape."

 

"The presence of either disease is most obvious when affected trees have been killed, and any concentration of dead or dying alders should arouse suspicion. Before they die. alders suffering from these conditions can display a number of symptoms, but the most obvious ones are tarry or rusty spots on the bark at the base of the trunk, or the presence of a number of dead branches in the crown. These symptoms can be seen from summer onwards."

 

Phytophthora disease is caused by a fungus that infects the roots of the tree and kills the bark at the base of its stem. The dying bark produces a tarry or rusty fluid that oozes out to form spots on the trunk. When most of the bark around the trunk has been killed by the fungus, the tree's foliage becomes sparse and its leaves are abnormally small and yellow. The leaves on infected alder often fall early, leaving them bare. Most infected trees eventually die and there is currently no effective treatment.

 

The cause of crown dieback in alder is unknown. The first symptoms are the presence of dead and dying leaves or leafless twigs in the tree's crown during the summer. The dead leaves and twigs are associated with extensive patches or strips of dying bark on the branches, although these are difficult to detect at first. However, death of the branch is usually progressive, and affected branches often die, giving the tree a skeletal appearance. Although alders can recover from dieback, dying bark often extends from affected branches into the main stem of the tree, resulting in its death. No effective treatment is known.

 

"We have confirmed three cases of Phytophthora in Scotland since 1996 - one on the River Spey and two on its main tributary, the River Avon," Dr. hendry said. "Two probable cases have also come to light recently on the Rivers Tweed and Dee."

 

"Crown dieback has been recorded in northwest Scotland since the 1980's and appears to have become widespread throughout the Highlands, with a few recorded outbreaks in southern Scotland."

 

"However, there could be other cases that we don't know about, and this is where the public can help us to establish the true extent of these problems, which will be vital in helping us to develop a strategy for tackling them."

 

Reports of suspected cases of Phytophthora infection or crown dieback in alder trees can be made to Dr. Hendry at Northern Research Station, Forest Research, Roslin, Midlothian, EH25 9SY; telephone 0131 445 6945; email steven.hendry@forestry.gov.uk

 

If possible, reports should include an Ordnance Survey map reference to the sites.

 

------------------

Elton Murphy

Anglers' Net

http://www.anglersnet.co.uk