Home to some of New Zealand's largest kauri trees, and other giants like rata, kahikatea and rimu, the area also supports wetland species such as swamp maire.
More than 60 nationally threatened animal and plant species have been recorded in or near the reserve site, including the only known scarlet mistletoe plant in the Northland and Auckland mainland region.
Birdlife includes the endangered kokako, which the trust expects to spread into the restored forest, and the North Island brown kiwi, for which the area is a stronghold.
Since 1980 the trust has established more than 7000ha of native forest and wetland as permanently protected nature reserves. It aims to preserve the beauty of these landscapes, and the wildlife they shelter, allowing current and future generations to enjoy nature and benefit from a healthier environment.
As well as enhancing local wildlife value, the trust believes that restoring the Wekaweka Valley site to its former glory will support larger-scale conservation in the area - including the proposed Kauri National Park.
"It's so important that areas as important as this are given permanent protection," Ms Crichton said.
"I would urge anyone who loves New Zealand's natural heritage to donate whatever they can."
Contributions both large and small will be welcome via www.nfrt.org.nz/wekaweka-appeal.