The Welsh borders have been invaded by a rush of young people in Lycra

You go mountain-biking with Jerry Gissop at your peril. He may be 48, and have a studious look about him; but not only does he ride regularly around Welsh border country, he also, when the spirit takes him, goes on ferocious bashes overseas. Thus he once rode - or, to be accurate, carried - his bike over the flanks of Mount El'brus, in the Caucasus, reaching 13,000ft. He has also powered home through the Pyrenees, along the northern coast of California and up through the Outer Hebrides.

He is now district forester in the Forest Enterprise's Marches District, centred on Ludlow. As such, he has responsibility both to entertain the public and to swell the Enterprise's coffers by earning as much from tourists as he can - and he has harnessed his passion for mountain biking to this end.

In general, the Enterprise welcomes riders in its forests. Only near towns, where walkers are numerous, does conflict arise. There, in Mr Gissop's experience, the problem is largely one of different generations: "The walkers who have traditionally used the forest tend to be over 40, and suddenly they find the place invaded by a rush of young people dressed in fluorescent Lycra."

Recognising that young bloods need places in which they can let off steam, Mr Gissop laid out a special trail in Hopton Wood, near Craven Arms. In this 1,000-acre forest, with nearly 20 miles of roads and tracks, bikers can take their pick of easy gradients on good surfaces, or, if they must, one-in-three logging chutes, on which they are liable to fly over the handlebars and break their collar-bones.

Another of Mr Gissop's schemes, in partnership with the country authorities of Shropshire, Herefordshire and Worcestershire, has been to devise routes that link scattered woods by means of quiet lanes. A third project, now taking shape, is to produce five loops of lanes and woodland tracks with accommodation available in pubs along the way.

To sample one of these, I rode forth with him on a typically foul Border morning, as heavy drizzle swept the hills. From the Riverside Inn in the hamlet of Aymestrey, we pedalled away along a main road, then turned off into More Hill Wood.

After a long grind upwards, which raised a good sweat, we cruised easily between trees in silence broken only by the occasional whistle of a buzzard. Sometimes we were on well-made forestry roads, sometimes on grass tracks, but all the time it felt that we had left the rest of the world behind.

Mr Gissop reckons that biking gives him time to think. Here it gave us time to chat, not least about the Enterprise's ever-more-stringent need to raise income. Such is the popularity of the forests among bikers that a single race at a place like Eastbridge, near Shrewsbury, can attract 1,200 entrants, each paying pounds 1 a head. Yet many of the smaller outlying blocks are so remote that they are scarcely visited.

The idea that bikes cause erosion in such areas (my guide observed) iswrong. On the contrary, they are often quite useful, in that they smooth out mud churned up by horses.

After an hour's agreeable exercise, we sped down towards the rushing waters of the River Lugg, and suddenly arrived back at the inn, where we put away a quite excellent lunch, cooked by a chef trained at Le Gavroche. Well fortified, we lashed our bikes on to the back of the car, drove a dozen miles north to Hopton, and launched off along the trail.

We climbed easily to the Titterhill - a heathery summit mound commanding a phenomenal 360-degree view. A clear map, and numbered marker-posts, each stamped with a triangle whose apex points north, made it simple to follow the prescribed route - but in fact we could have gone in any direction, across the contours or along them. In an hour's ride, we saw no one else.

Back at the car-park, glowing, I had no trouble in seconding Mr Gissop's contention that "the Welsh border country's made for cycling".