Bob Brown Foundation says Tasmanian logging company Forico is on a winner with its valuation of its estate at $8.6 billion if it keeps it growing rather than logged.

“This backs what I put to Premier Guwein recently: that, in this age of climate and extinction emergency, the island’s native forests are most valuable left growing, not logged,” Bob Brown said.

“But the idea of putting a dollar value on all of nature is daft. For example, what is the price of a Superb Fairy Wren, Golden Possum or Black Swan pair with cygnets?"