FIVE trees believed to be more than 60 years old and under a preservation order have been poisoned at Laund Clough in Baxenden.
The historic beeches were discovered with drill holes near their bases. It is thought that weed killer was then poured in, quickly killing the trees.
A spokesman for the Woodland Trust said: “This indicates that someone has set out to deliberately destroy these trees.
“As they are protected, this incident is a criminal offence and has been reported to Lancashire Police and the Local Tree Preservation Officer.”
The vandalism was discovered by site manager Colin Riley, who said: “During my 15 years at the Woodland Trust, I have never seen damage on this scale.
“I cannot fathom why someone would wilfully destroy trees in this way, especially given their age and protected status.
“Our native woods suffer enough from threats such as tree disease and a changing climate, without someone setting out to intentionally kill them.
“Laund Clough is enjoyed by the whole community and I would urge anyone with information relating to this incident to speak now.”
The Woodland Trust, a conservation charity, is now facing hefty fees of more than £2,000 to remove the trees for the safety of visitors to the area.
Philip Johnson, Tree and Woodlands Officer for Hyndburn Council, said: “I am extremely shocked and disappointed to see this blatant destruction of an area of the natural environment.
“Laund Clough is an incredible natural resource on the doorstep of local people, an area of great beauty accessible to all. Please help the Woodland Trust and the council in their search for the perpetrators.”
Anyone with information should call Lancashire Police on 101.
The Woodland Trust is currently running a campaign called VI Trees which is calling for a register for individual trees of National Special Interest, which over 12,000 people have already supported.