BBOWT volunteer Anna Feeney joins the team at Chilswell Valley Nature Reserve, where rare fenland promises exotic blooms

For Andy Gunn, Chilswell Valley Nature Reserve was more than just a quiet spot with a good view. “Walking up the hill away from the noise and stress of traffic jams on Oxford’s ring road towards the tranquillity of the fens and woods is kind of spiritual, even though that sounds corny,” he confided.

The Wild Oxford project officer was standing beside me on Chilswell Path halfway up the hill above South Hinksey and telling me about the extraordinary nature reserve where we were about to start work.

With the fields sloping away before us and Oxford spires on the horizon, I completely understood what he meant. A sense of leaving the bustle of the ‘big city’ and opening up a different view of Oxford is certainly part of the appeal for volunteers here. We were standing at the eastern entrance where the reserve begins with grassland on the sunny west-facing slope; but if you follow the new boardwalk it leads you over a fen before taking you into deep wood. The fen in particular, Andy told me, is what makes this reserve truly special.

While fens, along with bogs and marshes, aren’t always thought of as extraordinary, the calcareous fen at Chilswell is extremely rare – in fact, there are only 19 hectares in England.

Fen is formed by water that first travels through a layer of limestone before hitting a layer of clay. When the water hits the clay it forms a pool where, over thousands of years, vegetation has grown and decayed to gradually build up an alkaline peat bog.

This wonderfully nutritious fen is irresistible to beautiful and rare species of plants. With restoration work now going on it is hoped the dormant seed that’s been hidden for years in the fen will once again thrive.

The exotic-sounding Grass-of-Parnassus, the beautiful marsh helleborine orchid, and the insectivorous bladderwort thrive at other calcareous fens such as the Lye Valley in Headington, which is another Wild Oxford site, and Cothill Fen near Abingdon. So there’s every chance that they will at Chilswell Valley.

Many larger plants enjoy the fenland habitat too. Fine oak, ash and hazel trees can be seen sprouting out of the marshy ground, along with reeds. The reeds actually grow so quickly that they have to be cut back on a regular basis, which is what Andy and his team of volunteers were about to do.

Because this landscape is so special and needs extra care, volunteer groups come here every six weeks. It’s a real community with people who’ve been helping for years welcoming and teaching those who are newer to the game. There are students from St Clare’s College in Oxford working towards their International Baccalaureate, local families, and others who just want to spend some of their weekend outside working with the local wildlife.

They all use techniques and tools that are centuries old. The rakes used to clear up the debris are not, I learn, any ordinary rakes — only one family in Cumbria still makes them, and has done since the 1890s.

Watching the youngest volunteer, 12-year-old Ben, striding around with stacks of reeds hoisted over his shoulder, made me feel as if I had gone through a time-warp; I could imagine a boy of his age doing the same task of raking up the reeds, with the same equipment, more than 100 years ago.

After leaving at the end of the day I felt exhilarated and full of admiration — for the reserve’s history, for the number of amazing species there, and for the dedication shown by those volunteers. As I cycled back to Oxford over the A34, I knew I’d have to come back soon.