Brechfa Forest, Carmarthenshire: A walk that streams into springtime

As he follows the river Gorlech, Mark Rowe is accompanied by birdsong, budding trees and an experimental forest garden

Brechfa Forest, Carmarthenshire

What's on your wish list for a lovely spring walk. Bird song? Budding trees? Perhaps a rushing river glistening as the sun finds its strength? And a brilliant pub? One by one, I happily tick them off as I hike up the Afan Gorlech, a river that crashes its way through Carmarthenshire.

The Gorlech threads its way through the huge Brechfa Forest. I'd heard of neither before heading for this northern part of the county, but the forest is substantial enough to have its own Ordnance Survey map. And all those trees and water make it a premium location for wildlife once spring commences.

The first stretch, a half-mile riverside stroll, is almost ineffably delightful. The path runs alongside the Gorlech. Shallow in parts, it's secure enough for children to paddle in between playing pooh sticks on the bridge. The water has a mesmerising amber colour, and the sun bounces off the protruding rocks before fading into the greens of the ranks of conifers.

Blackbirds, blue tits, great tits, coal tits, and robins, zip back and forward, busily gathering nesting materials or chirpily flaunting themselves to prospective mates. The dipper is the most graceful. Like a hovercraft it floats across the water, following the currents and contours, allowing fleeting glances of plumage that includes a distinctive large white bib.

Walk of the month: Brechfa Forest, Carmarthenshire

After the bridge, though, the walk rolls up its sleeves. Up we go: a stiff series of hairpin climbs take us high above and deep into the river valley. I'm struck by the razor-sharp changes in colour as I pass hundreds of densely packed birch trees. Those parts of their stems that get little or no direct sunlight are mantled in mosses. Where they break through the canopy their bark becomes a glistening silver, like bony fingers sticking out of fingerless mittens.

The steep climb is the only meaningful ascent and the paths, easy on the eye, thread their way gently through the forest. Moss-covered stumps of fallen conifers make for good places to sit and stare. Downstream, the river was nimble, seemingly holding its breath as it squeezed between the rocks. Up here, the Gorlech has a real swagger, crashing and muscling its way through a larger landscape. You could pass around a photograph of the river here, claim it to be of Alaska or the Rockies and not be challenged.

The walk has one final surprise. The path loops up to a giant arboretum, Brechfa Forest Garden, hidden away from the rest of the world. Sprawled over several acres are 89 of the 189 tree species that will grow in the UK. They date back to the 1950s, and an experiment by foresters to see just how many trees could be grown for timber. I crane my neck at giant redwoods, Macedonian pines, Norway spruces. There are deciduous trees too, coming into leaf: lime trees, walnut oaks and South American beeches.

The sight of exotic trees in bloom seems a little surreal: it's spring, but not as we usually know it in the UK. Then there's the eucalyptus grove high up in the garden, which spring tends to pass by, the leaves and bark about as much use as a potato to passing wildlife.

The route back follows a quiet timber road. Where lorries laden with timber have eroded the track, puddles have formed, many containing frogspawn, another nudge that spring now holds the upper hand.

The Cothi valley – into which the Gorlech flows – offers not only a classic view of spring unfolding before your eyes, but is also a microcosm of Britain. Only recently, the valley's communities were faltering, with school, post office, shop and pub closures looming. Elsewhere in the forest is a derelict smallholding called Tanrallt, one of a number of ruins that show attempts at a self-sufficient "good life" do not always prove successful.

After such a life-affirming walk, I'm heartened to find these threats were not being taken lying down. A community shop has opened four miles south in Brechfa village, while the Forest Arms pub has been rescued. With a menu that draws on local ingredients, it too, like the countryside, is blooming. Spring is a time for lambs, and appropriately a local dish, cawl pie, is on the menu. "It's a traditional lamb stew, except we made it into a pie," smiles the ever helpful landlord George Rashbrook.

Later, I get a fresh perspective on the landscape by taking the Gwili Steam Railway up the parallel valley from Bronwydd Arms just north of Carmarthen. It's a delightful journey and this year, marking 50 years since it was closed commercially by Beeching, it has an extra spring in its step. It criss-crosses the Gwili and again I pick out dippers frantically skimming the river surface seeking food and mates. No time to dally, spring is on the way.

DISTANCE: Five miles/eight kilometres

TIME: 2.5 hours

START/FINISH: Forestry Commission car park at Abergorlech

OS MAP: Explorer 186 Llandeilo & Brechfa Forest

Directions: the Forest Garden walk can be found at bit.ly/BrechfaWalk. Otherwise, from the car park, just follow the red trail markers for the length of the walk.

Getting there

The closest main line railway station is Carmarthen, served by Arriva Trains Wales and First Great Western (08457 484950; nationalrail.co.uk).

Staying there

Mark Rowe stayed as a guest of Discover Carmarthenshire (discovercarmarthenshire.com) at Brechfa Lodge in Brechfa, where three nights' rental start at £364, self-catering (01239 810033; westwalesholidaycottages.co.uk).

Visiting there

Gwili Railway (01267 238213; gwili-railway.co.uk).

Forest Arms, Brechfa (01267 202288; forestarms.com).