The Greta retiree has grown national champion orchids, and is known as a bit of a celebrity in the orchid world.

He was a successful cow cocky for many years.

Towards the end of his career, Mr Cruickshanks started work as a cattle manager at Rosemount Vineyard and ended up growing grapes.

“I believe whatever you do, you put everything into it,” Mr Cruickshanks said.

But it’s his latest venture that is perhaps most impressive.

Mr Cruickshanks has entered 14 national champion trees on the National Big Tree register.

Trees have always been a joy for Mr Cruickshanks from his work on the land.

After he retired he started taking day trips with his wife where they would explore bush areas and enjoy the trees.

Mr Cruickshanks’s sister saw a story about the register and told him about it.

So he started entering a few of his finds… and boy were they winners.

“When I found a big tree, it just turned out that these trees were bigger than any anyone else had found,” he said.

He has now entered 29 trees on the register, half of which are national champions.

Mr Cruickshanks’s tallest discoveries include a 67-metre gum tree at Johns River and a 62-metre blue gum at Barrington Tops.

His favourite is the 60-metre Blackbutt "Benaroon" he found at Johns River in 2013, with a circumference of 15.1-metres.

Finding these big trees is pretty special to Mr Cruickshanks, but he said it’s no different to succeeding at any other hobby.

“It’s something to be proud of I guess,” he said. “It makes me happy.”

“But its just like winning a game of bowls or winning an orchid competition.”

After 18 years searching for forest giants, Mr Cruickshanks is just about ready to hang up his boots.

National Register of Big Trees coordinator Derek McIntosh said he thought Mr Cruickshanks’s contribution to the register had been “quite amazing”.

He said the only person who had contributed more to the register was professional botanist Dean Nicolle.

“As far as private people go, Don’s top of the pops,” Mr McIntosh said.