"It's part of a long-term project and we will keep working at it. Each year a new set of children will add something to the sculpture, so it will develop and change. We have planted a lot of trees around the school, and in five years we should have enough for biomass (organic material renewably used as fuel). Then the kids can crop it, dry it and sell it.
Besides basketry, sculpture and biomass, the willow tree area will be an outdoor classroom for cross-curricular learning - as well as for studying the life-cycles of plants, the factors affecting their growth and the local wildlife.
"It's all about conservation, which has been a constant at Firth for many years," says Mr Moar.
What changed last year was that, in competition with schools all over Britain, Firth Primary won a total of pound;15,000 for their willow tree project from the Rolls-Royce Science Prize. They also received a special environmental education award from Tim Smits' Eden Project. A small rural school of 80 pupils on Mainland Orkney, Firth Primary planned its winning initiative with the help of local enterprise, craftsmen, artists and environmental experts.
"It was very much a team effort, which the judges liked," says Mr Moar.
"We've got a long history of active involvement in environmental education -active in the getting-your-wellies-on and getting-your-hands-dirty sense.
You have to think about the future."