The concerned students, under Allen's quiet leadership, hatched an ingenious plan to save the kūtai.
First they spoke to kaumatua and community leaders, then they enlisted local government, business and community support to collect more than $1000 worth of prizes.
Then, tapping into their community's pride and competitive streak, they organised a competition to see who could collect the most pyura in a day. More than 60 competitors gathered half a tonne of the pest - and one youngster collected a massive 78kg.
Allen's next stroke of brilliance was to set up a business venture through the Young Enterprise Scheme producing fertiliser from the dead pests.
The judges said Allen was a "passionate environmentalist and budding entrepreneur who creates change right here, right now, in his own community".
Allen said he was "completely blown away" by his win.
"To be picked out of all the rangatahi, all the young leaders, is actually quite humbling," he said.
Next year Allen, who is in Year 13, will work on the Puhoi-Wellsford motorway extension, but he also plans to carry on his work of bringing together communities whose kūtai are threatened by pyura.
His father, Tangiroa Karena, said he was grateful to teacher Nadine Scally for nominating Allen for the award.
"We're very proud of him as parents and we know our community will be very proud of his achievements."
Also present at the awards night was Aaron McCloy, of Papa Taiao, a company which offers ecological restoration training courses, including at Panguru Area School.
McCloy said he was "phenomenally proud" of Allen, who "stepped up very quietly and got on with the job" when the pyura project needed a leader.
"Lots of students have opportunities but he really took that opportunity and made it reality."
The runner-up in the Youth Community Spirit Award was Phoebe Huett, head girl of Springbank School in Kerikeri.
Among her many volunteer roles she looks after Riding for the Disabled's horses during the summer break and has helped charity Foster Hope, which provides essentials to Far North children in foster care, for the past five years.