THE tiny trees growing at a secret location represent the survival of an entire species in the North-East.

Black poplars are extremely uncommon across the region, and although a small number cling to existence in Northumberland, Tyneside and Wearside, Darlington is their stronghold with about 35 growing wild.

Darlington Borough Council has been working with the British Trust for Conservation Volunteers (BTCV) to save the tree by growing saplings to be reintroduced into the local countryside.

The key to the success of the project is the 600 cuttings at the BTCV nursery, which is hidden away in the Brinkburn area. They vary in size between several feet and a few inches, and many are less than a year old.

Eight schools and several local people have also grown trees as part of the project.

A hundred trees were planted out late last year, in conjunction with the Tees Forest and Forest Enterprise, at the new South Burdon Community Forest, on the eastern edge of the town. A-hundred-and-fifty more are due to go out next winter on urban sites, including The Denes and, possibly, South Park, and on farmland.

Many of the surviving Darlington specimens are on wetland sites. Several are on farmland near Middleton St George, and others are scattered along becks and similar sites. There is also one in South Park.

The black poplar is listed among the North-East's top 30 endangered species in the Durham Biodiversity Action Plan, which identifies action needed to preserve threatened species.

Research by BTCV volunteers has added extra urgency to the initiative. Helen Tomb, BTCV project officer, said: "The ones we have found have reached maturity, and some of them are beginning to die back. The situation is critical and this project is about saving the tree.

"This project has been really successful and we are receiving queries from other councils who want to find out how they can adopt black poplars. Darlington is leading by example."

Sarah Storey, council countryside community officer, said: "Our aim is to plant out 500 in five years. The 150 which go out next winter will be going on sites across the town and also in the corners of fields."

Growing native

* Black poplar is a native tree and grows to 100ft

* It has gnarled bark and dipping boughs

* Although more numerous in the South, populations remain rare and fragmented

* It was used for building, partly because the timber has low flammability, and for matches because it absorbs paraffin

* It fell into commercial disuse 200 years ago and declined rapidly.