In the heated exchange with well-known anti-deal campaigner Kelly Wilton, Mr Mulder said the deal was ``crap'' and ``guaranteed to fail''.

He writes: ``So let's get some fed dollars, watch it fall over and then let the industry rebuild.''

In a later email, he explains that his intent is to demand the environmental signatories to the deal deliver on their end of the bargain before granting the asked-for 504,0000 hectares of new reserves.

``My intent is to put them to the sword,'' he writes.

``If they can't then deal off, and we never need to negotiate with them again.''

In the final email, he explained that he was trying to navigate a way through two opposing sides, and said Mrs Wilton was welcome to ``spread the word''. 

Mrs Wilton says she was shocked and offended by the comments, which she posed on her Facebook page ``Support Tassie's timber industry like they have supported Tassie for years'' on Wednesday. 

``It shows a lack of understanding or respect for what people are going through,'' Mrs Wilton said.

``If he wanted the deal to fail, he should have voted against it, not played games.''

Mr Mulder was one of eight MLCs who supported the heavily amended deal in the upper house this week, after he successfully moved to delay the proclamation of reserves.

He acknowledged the emails, but said they were sent in response to a ``very, very provocative'' email sent to all MLCs in an attempt to acknowledge Mrs Wilton's views.

Mr Mulder said he had publicly and consistently said he thought the Tasmanian Forests Agreement was a ``crap deal'' but   if he had wanted to destroy it, he would simply have voted it down.

``If I didn't think it was worth a go, if I didn't think it stood a snowball's chance in hell, I would be the first person to say: `let's cut this thing','' he said. ``I am clearly motivated by trying to get something up that could work.''