In little plastic cups, he "raised" the young of an endangered tree, and cared for the seeds like they were his children.

This was in 2002, when Dr Shawn Lum, then vice-president of the Nature Society (Singapore), learnt of the illegal felling of the endangered Hopea sangal - in Changi Village. Fortunately, seeds were collected before the felling and Dr Lum, an American and permanent resident here, helped them grow into strong saplings over the next eight years.

"I don't have any children of my own, but I know where those Hopea sangal are planted," he said at a media conference recently, after being named one of three recipients of the President's Award for the Environment (PAE) this year.

The saplings, including those grown by the National Parks Board ( NParks), were planted at the Singapore Zoo, Changi Airport, Botanic Gardens and Changi Museum.

Dr Lum, who is now president of the Nature Society (Singapore), received the award for his significant involvement in biodiversity projects in Singapore.

Professor Leo Tan, director of special projects at the science faculty at the National University of Singapore and one of the nine judges of the awards, said: "Dr Lum should have won this award long ago."

Anchor Green Primary School won the award in the institution category. The school collaborates with firms such as Ikea and Brother, as well as the World Wide Fund for Nature Singapore and NParks, to promote recycling and conservation.

Khoo Teck Puat Hospital (KTPH) picked up the award in the organisation category for its "hospital in a garden and a garden in a hospital", as Mrs Chew Kwee Tiang, chief executive officer of KTPH and Yishun Health, described it.

This is the second time a hospital has bagged the organisation category. Alexandra Hospital won it in 2008.

The awards were presented by President Halimah Yacob at the Istana last night. The PAE, now in its 12th year, had 48 nominees this year, and the three winners were selected by a panel of judges.

From next year, the awards will be a biannual affair to better cultivate potential nominees.

Dr Lum said although the winners are from different fields of work, "the three of us have an overlapping theme: Nature is a part of everything. By taking care of the local environment, we make sure there's space for people and for nature".