More than 80 Canberrans planted 760 trees near Pine Island at Tuggeranong, with each tree representing 10 Australians who die from lung cancer each year.

Medical oncologist David Leong planted trees with his 10-year-old daughter Emily. He thought of the lung cancer patients he had treated who hadn't survived.

Dr Leong said a quarter of the 9000 Australians diagnosed with lung cancer each year had never smoked.

''I would see at least two lung cancers a week, every week consistently,'' he said.

But a new study has found Australians are less likely to be sympathetic when it comes to patients diagnosed with lung cancer.

The Global Lung Cancer Coalition found three in 10 Australians said they would feel less sympathy for a lung cancer patient compared to people with other cancers because of its known ''link to smoking''.

Long-time smoker Gay Priest, of Hughes, was diagnosed with lung cancer in April. She said she was ostracised because she had smoked prior to her diagnosis.

''I have a friend who was recently diagnosed with breast cancer and the whole team that surrounded her from the day of diagnosis was incredible,'' she said.

''Even now I don't know if it's because I was a smoker but I was virtually ignored and it's a scary place to be.''

Event organiser Judy Rafferty said no one deserved to get cancer and nicotine was the most addictive substance on earth.

Dr Leong said said smoking was no longer the most common cause of lung cancer.

''Now that smoking rates have declined to one of the lowest in the world, we still are seeing a lot of lung cancers but they are of a different type. In fact it happens to be more in females who have never smoked.''