What is killing Britain’s street trees?

Trees in Britain are struggling to come to life this winter following outbreak of disease, gritting of roads and over-zealous health and safety. Climate change and the increasing movement of horticultural plants around the country has increased the risk of disease. Chestnuts are suffering from bleeding canker and a leaf miner moth and many have had to be killed on Britain’s streets. Oaks, that are more often found in parks, are being killed by acute oak decline. And Japanese larch, that is a popular ornamental tree, is dying from sudden oak death. Heaving gritting over the roads over the last two winters has affected trees. Rock salt – or sodium chloride – is the most popular and cheapest treatment used by gritters, but when the ice or snow melts the toxic runoff can easily seep into soil – starving trees of moisture. Salt will also subject the roots to ‘toxic attack’ – causing them to slowly die off. Councils are increasingly nervous about falling branches and hay fever. A line of 200-year-old trees were felled in Bradford after one fell down in a storm and apple trees were chopped down in North Yorkshire for fear fruit would fall on people’s heads.

Thousands of trees around Britain are in danger of dying after being killed off by gritty salt used to combat icy roads and pavements over the tough winter.

By Louise Gray, Environment Correspondent
19 Feb 2011 After the coldest December on record, gritters were out in force all over the UK this winter to make roads and pavements safe. Councils had stocked up on salt after the coldest start to the year in 30 years in 2010. However two years of spreading huge amounts of salt on the road is starting to show in wilted and dead trees this spring. Rock salt – or sodium chloride – is the most popular and cheapest treatment used by gritters, but when the ice or snow melts the toxic runoff can easily seep into soil – starving trees of moisture. Salt will also subject the roots to ‘toxic attack’ – causing them to slowly die off.
Emma Hill, Policy Director at Trees for Cities, said the true scale of how many trees have been killed off will only become apparent in spring, but there is concern it could be thousands. “Salt grit obviously has a detrimental affect on trees. The gritting salt leeches into the soil around the tree and draws moisture out of the roots leading to signs similar to drought. It can eventually kill the tree. We will be monitoring our trees at bud break in spring to see the extent of the damage after the coldest December for a century lead to heavy salting,” she said. A spokesperson for the Forestry Commission said: “The use of excessive amounts of salt to de-ice roads and paved areas can be seriously damaging to trees and plants. Following the current cold snap we do expect to receive some enquiries in the spring when trees fail to flush, and we expect to find in some cases that they have been killed or damaged by excessive salt in the soil.” Southwark Council in south London has already raised fears that by spring ‘hundreds’ of the borough’s trees will be dead and are putting in place new plans for next winter. … Tree expert Dr Bruce Fraedrich, director of the research laboratories at Bartlett Tree Experts, says many trees around the UK will have been affected by rock salt. He said that salt can ‘desiccate’ trees – causing them to dry out like they would in a drought – after they absorb the sodium chloride into their roots. …