Hundreds of trees are to be removed from the TT course.
Disease is affecting ash, elm and larch trees.
It means that road traffic management measures will be in place on separate projects on the main road between Ballacraine and Sulby Bridge over the coming weeks.
Hundreds of dead and diseased trees will be removed alongside a section of the TT Mountain Course at Glen Helen to ensure public safety.
The trees, many of which pose an immediate risk to road users, will be removed within a 15m-wide and 1.2km-long corridor between Laurel Bank and Sarah’s Cottage on the A3.
The majority of the trees — comprising ash, elm and larch — are on government-owned land and tree health issues were first identified in the area during a proactive survey by the Department of the Environment, Food and Agriculture in 2021.
A follow- up assessment by trees experts in the summer revealed a significant decline in many trees and an unacceptable level of potential failure near the roadside.
Clare Barber MHK, Minister for Environment, Food and Agriculture, said: ‘The department has a duty of care to ensure its lands, glens and plantations are safe for users and passing motorists, and must act to address the risk from multiple tree failures which have the potential to cause significant damage or worse.
‘Although there is minimal public access within the steep-sided Vaaish Plantation there will be a noticeable change to the landscape, which is unavoidable. All trees will be fully inspected for wildlife, such as bats, before removal.’
There are two primary pathogens causing ill health.
Phytophthora ramorum, which can affect more than 150 different plant species, but in this situation is causing the death of the larch trees; and Hymenoscyphus fraxineus (ash dieback) which affects ash.
Additionally, there are several secondary pathogens, such as Honey fungus, Shaggy scalycap and Dyers mazegill, which are contributing to the rapid decline.
During the project, a number of other invasive plant species, such as rhododendron and cherry laurel will also be removed.
The area will be replanted over the next two years with carefully chosen native broadleaves, which are suitable to the location and less susceptible to known plant diseases.
The work will begin tomorrow (Wednesday) and take around 10 weeks to complete. It will be undertaken in phases in order to avoid conflict with the Mountain Road closure in April:
Phase 1: March 8 to 26 – traffic lights 24 hours a day; March 27-31 – road closure 9.15am and 4pm daily with diversions in place
Phase 2: May 2 to 23 – traffic lights 24 hours a day
Homeowners and local businesses in the area will be given with progress updates.
Race organisers also have identified a section of Sulby Straight that requires improvement prior to the running of the 2023 Isle of Man TT Races.
While the road surface is in a good condition under normal driving conditions, movement beneath the ground is causing it to undulate, leading to challenges for riders at race speed.
A 10-day project is scheduled to start next month to help ensure the Mountain Course is in its best possible condition for this year’s event.
Gary Thompson, clerk of the course for ACU Events Ltd, said: ‘The condition of Sulby Straight was the subject of several remarks from riders during last year’s event in terms of poor ride quality.
‘As the organisers of the Isle of Man TT Races, minimising all controllable risk to competitors is our priority and something we routinely review as part of our safety management system.
‘Following a risk assessment carried out by ourselves, and in collaboration with the Department for Infrastructure, we have requested that work takes place on the affected stretch in order to improve the area for the 2023 event.’
Traffic lights will be used while work takes place on a 300-metre stretch of the highway.
A road traffic order is in place for three weeks, from Monday, April 24, and will allow the DoI’s highway services team some flexibility around start and finish dates as TT preparation work draws to an end on the Mountain Road.
Exactly when the Sulby Straight project will begin will be announced closer to the time as it becomes clear when staff will be able to move from one project to the other.
Infrastructure Minister Chris Thomas MHK said: ‘The highway services team have reacted quickly to come up with a solution following a request from ACU Events Ltd and look forward to delivering an improved surface for this year’s races.
‘It’s important to note that this will represent a temporary fix and that a more significant project will be required in the future.’