Tony Finnerty, who is the manager of the Bonny Glen Wood in Portnoo, says he has no doubt somebody started the fire in the wood maliciously.
The claim has backed up the theory that dozens of the gorse fires which caused havoc across the county in recent days were as a result of arson attacks.
Finnerty is still counting the cost of the fire which destroyed thousands of mature 28 year old spruce, pine and larch trees.
He estimates that a devastating 400 hectares of forestry may have burned to the ground in the blaze.
An investigation into the forest fire, which at one stage travelled 800 metres in just three minutes, is ongoing.
“They (the gates) could only have been removed using a heavy-duty vehicle like a digger. It’s only my personal opinion but I don’t know why some people do these things.
“Someone decided they didn’t like our forests, and they started those fires. They were lit,” he said.
And added “It’s catastrophic. That’s all I can say. The tax-payer is the real loser here.”
Chief fire officer Bobby McMenamin said he too suspects that many of the fires which swept the cont last week were started deliberately.
He said the fact that five fires started in Buncrana in just one day was not a coincidence, for example.
“It’s obvious somebody was doing something they shouldn’t have been doing,” he said.