The 12- and 13-year-old girls from Beaconhills' Village Campus in Berwick formed HELP - Helping Endangered Leadbeater's Possums - to rejuvenate the possum's natural habitat and to raise awareness of its demise.

The possum, Victoria's faunal emblem, is critically endangered since Black Saturday's fires destroyed 43per cent of its natural habitat.

About 1000 Leadbeater's possums are left in three known colonies - including the Lake Mountain region, where numbers shrank from 100-300 to just six.

HELP, supported by the Healesville Sanctuary and Friends of Leadbeater's Possum, planted more than 100 trees in three days in Yellingbo.

Student Elly Robertson, 12, is hopeful a wristband drive and a segment on Channel 10's Totally Wild will boost sponsorship for nesting boxes made from special recycled plastic and now used as temporary homes for the Leadbeater's possum.