A moonlight trek to where the wild things are ...

It's boots on and back to nature for Mike Higgins in the forests of Norway, and, below, Mary Novakovich in volcanic Costa Rica

Did you know that there's a technique for walking rocky paths? No, nor did I until I went to Femundsmarka National Park in central Norway. You place your shoe or boot directly on the rock and roll your foot over the top. As you do so bend your knee, that's it, keeping your head more or less level. Yes, it is a little Groucho Marx, but trust me, in the other-worldly eerie landscapes of Femundsmarka, an unorthodox gait comes in handy. On my five-day, four-night wilderness trek through Femundsmarka I strode along contour paths, scrambled over boulders, squelched through bogs, splashed through lakes and sprang across ... well, we'll get to the bouncy stuff later.

Did you know that there's a technique for walking rocky paths? No, nor did I until I went to Femundsmarka National Park in central Norway. You place your shoe or boot directly on the rock and roll your foot over the top. As you do so bend your knee, that's it, keeping your head more or less level. Yes, it is a little Groucho Marx, but trust me, in the other-worldly eerie landscapes of Femundsmarka, an unorthodox gait comes in handy. On my five-day, four-night wilderness trek through Femundsmarka I strode along contour paths, scrambled over boulders, squelched through bogs, splashed through lakes and sprang across ... well, we'll get to the bouncy stuff later.

Femundsmarka is a pristine example of wilderness. The park lies on a 1,000m-high plateau about three hours' drive north of Oslo, and its 390 square kilometres are bounded to the east by the national border with Sweden and to the west by the long lake, Femunden, which gives the park its name. Ten thousand years ago, glaciers covered the terrain, but making your way through the park you would have thought that the ice retreated just a few decades ago. The undulating topography to the south looks freshly sculpted, while boulders, five, seven, nine feet high, litter the centre and north of the park, left as they were deposited by the retreating ice.

The trek began after a night in a very comfortable log-built refuge - one of an impressive network of state-run refuges - just to the north of the small lakeside settlement of Elga (home, incidentally, to the southernmost community of Laps in Norway). Our group of five, including our Norwegian guide, John Riise, set off on a bright and breezy day. The first two or three hours were uneventful, traversing country not unlike the Lake District, with gorse and flat rock.

From the gently rising northern slopes of the 1,400m peak Store Svuku, however, an altogether stranger landscape rolled out before us: the streams and marshes in the valley below were familiar enough, but the stunted, sparse forest was not. The thin layer of soil over the glacial boulders, John explained, prevents the native birch, ash and pine from thriving conventionally. The pine is oddest of all: it twists round on itself as it grows, so that it doesn't grow too tall and destabilise itself: here, a 30ft tall tree might be 100 years old.

Soon we were threading our way behind John through glades of these contorted pines, over picturesque streams and around small marshy lakes - could we really have been walking windswept moorland just an hour before? The going underfoot was soft but under John's eye we meandered, picking and eating cloudberries. This, the guide warned us, is troll country.

Come six in the evening, and after about 12 miles of walking, we set up camp on the idyllic, wooded shore of a lake. What signs of humanity had we come across? A couple of other backpackers and a kayaker; even the log cabins used by the fishermen have turf roofs so that you're within feet before you clock them. Fortunately, John carried most of the camping equipment in his backpack, leaving the rest of us with a 15kg load each and enough energy to gather firewood for the planned evening meal: grayling or trout or perch, we were told, because in Femundsmarka is to be found Norway's finest sport fishing.

As we cast our lines into the lake, the late setting sun before us, John explained the particular quality of Norwegian national parks. "No motor vehicles are allowed here, or helicopters - the only way in and out of Femundsmarka is by foot," he told us. "That isn't the case in the Swedish park, just across the border." By the campfire, he explained with a grin that we weren't merely camping, we were practising the Scandinavian ethos of friluftsliv (literally, "free air life"). The term was coined by the Norwegian writer Henrik Ibsen and encapsulates a belief, still keenly practised by his countrymen, in the outdoor life. The term doesn't translate simply (grappling with it, it's hard not to entertain the stereotype of Scandinavians romping semi-clothed from sauna to plunge pool through fir-tree forests ...).

But before we deluded ourselves that we were worthy acolytes of friluftsliv, we had to face up to our catch from the evening's fishing: precisely nothing. None of us, it has be said, was an angler, but still, John said, this was uncommon. Out came the rations that John usually takes on the military outward bound courses he also runs, and into the pot. Thankfully, Norwegian army spag bol tasted a lot better than it looked and we whiled away the night by the campfire trying to imagine comparable wildernesses around the world: Canada perhaps? New Zealand?

After a comfortable night in the two-man tents and an oatmeal breakfast, we were off at about 9am, picking a tortuous route between the waterways all around us to a spot that John hoped would be suitable for a highlight of the wilderness trek, a river crossing. The consensus was yes, but our resolve wasn't put to the test: the waters at the point John had chosen for the crossing were too high for us to wade through. Our disappointment (mild, it has to be said) was short-lived - soon after, while resting on a fallen pine tree, we saw the only big game of the trip.

The park is home to wolverine, the occasional bear - and reindeer which is what we were watching now, about 50 yards off, a fair-sized lone male. "We are lucky," John explained. "In the spring they are more common, but not in the autumn - they are shy and, though they might be 300kg, they are very agile and quiet moving across land. This one probably escaped from one of the domesticated herds that are reared for hunting." Shy perhaps, disdainful definitely - the reindeer nibbled some vegetation and sloped off.

On we pushed, to be met by 10 miles of extraordinary walking. Reinlav is a species of lichen, small and green, and a staple of the reindeer diet. More important than that, it is a treat to walk on, both yielding and bouncy. Which was lucky because the boulder fields that lay between the reinlav meadows were much harder going, closer to rock scrambling than to walking. It came as no surprise to discover that the wilderness trek had been plotted by none other than Borge Ousland, Norway's most famous living explorer and the first person, in 1994, to walk alone and unsupported to the North Pole. Ousland rates the trek as suitable for those who regularly hillwalk, and he's largely right - just don't underestimate the difficulty of the boulder fields.

After another night on the Norwegian army rations - we were too knackered to fish - I was determined to show our guide that the boulders hadn't finished off his British guests. So the next morning, early, it was into the brown, brackish waters of a nearby lake for a morning dip. Refreshing isn't the word - it wasn't until I could feel my toes again that John told us that Femunden is the coldest lake system in Norway.

From there it was a couple of hours to the shores of Femunden itself to be picked up by a ferry for the return trip to Elga. There, at our final night's accommodation, our heads and hearts overflowing with the spirit of friluftsliv, we experienced the trek's most moving communion with nature: a large plate of reindeer and elk steak, rare. Ibsen would have been proud.

GIVE ME THE FACTS

How to get there

Norwegian Airlines (00 47 2149 0015; www.norwegian.no) flies direct from Stansted to Oslo with return fares from around £70. Wild Dog Adventure (00 47 9346 4128; www.ousland.no) offers a five-day Femunden Wilderness Trip from €695 (£496) per person, based on two sharing. The price includes a tent, all food, a stove, a sleeping mat and the final night at a guesthouse.

Trips start on 6 and 13 July, although additional dates will be added.

Further information

Innovation Norway (0906 3022 003. Calls cost 60p per min; www.visitnorway.com).

...or you could just go with the lava flow

"You'll want to drink this while you're in Costa Rica," our guide Juan Carlos said, introducing us to the loveliness that is Imperial. "We call it aguila, because of the black eagle logo." I speak little Spanish, so the addition of dos aguilas, por favor to my meagre vocabulary was very useful.

We also learnt the catchphrase pura vida - pure life. It means "hello", "cheerio", that's great, mate", whatever you like. Pura vida is one of the many beguiling things about Costa Rica, a small country full of bewildering contrasts and beautiful, bizarre scenery.

We set out for Lake Arenal, home to one of the country's many volcanoes. At the small café in Mirador Cinchona, a look-out post over a vast garden that resembled a compact rainforest, complete with toucans, hummingbirds and a huge waterfall, a six-year-old offered us her pet tarantula to hold. It felt deliciously creepy.

Back on the road, Juan Carlos braked abruptly and skidded over to the kerb. "Sloth!" he called out. We scrambled out of the car and looked excitedly up in the trees. Sure enough, a three-toed sloth was making its leisurely way down the tree. What a delight.

After another few hours over Costa Rica's atrocious roads, we made it to the Arenal Observatory Lodge. Arenal last had a major eruption in 1968, when 80 people died and new mountains were created by lava flow. It's still active, and on a clear day you can see steam blowing out of it; on clear nights a stream of red lava flows down.

Our first walk was through cloud forest to the crater of the neighbouring volcano, Cerro Chato. It's a steep enough climb when the weather is dry, but recent, relentless rain had turned the terrain into rivers of mud. Now and then a flash of vivid orange ginger lilies would appear; a greedy baby boa constrictor had choked to death on a lizard. More cautious, we ate with our heads literally in the clouds.

Juan Carlos had promised us hot springs. While the most famous is Taracon, expensive and usually overcrowded, we soothed our aching muscles in the more intimate Ecotermales Fortuna, which has four large pools descending into each other. Mercifully, it had stopped raining long enough for us to lie in the steamy water and watch the bats, swooping madly as dusk fell. The restaurant served an extremely good version of the Costa Rican national dish, casado: rice and spicy refried beans with extras such as chicken and beef, palm heart salad and fresh fruit juice.

On the way out of Arenal and around its enormous lake, groups of howler monkeys hung about in trees, and gangs of cuddly coatis ventured out into the road. The change was abrupt as we crossed the continental divide into another climactic zone: lush rainforest turned into hot, dry savannah with more volcanic mountains beyond. We were heading towards the Nicaraguan border for Rincon de la Vieja, another of Costa Rica's national parks, which in total make up more than a quarter of the country's land mass.

It's amazing what a bit of dry heat will do for the spirits. I knew I was going to like the Hacienda Guachipelin, a working cattle ranch with an open-air restaurant and bedrooms in single-storey lodges, but the walking wasn't any easier because it was dry. The primary forest was alive with spider monkeys trying to pee on us. We walked across a hanging bridge over a ravine, gazed at impossibly tall trees with enormous buttress roots that looked like dinosaur tails, and strode through vegetation that wouldn't have looked out of place in a 1960s Star Trek.

Admittedly, the walk back in a temperature of 38C was a bit of a killer, but we were rewarded by the sight of a dung beetle hard at work pushing its coated egg, and numerous sauntering iguanas: if you want to get close to Costa Rica's riches, you have to put in the graft.

GIVE ME THE FACTS

How to get there

The writer travelled as a guest of Headwater Holidays (01606 720199; www.headwater.com), which offers a 12-day escorted walking holiday from £1,838 per person, based on two sharing. The price includes return flights from Gatwick, transfers and full-board accommodation. The tour includes regions mentioned in the piece, the Pacific coastal resort of El Ocotal and the Monteverde cloud forest reserve. The next departure date is 26 April.

Further information

Costa Rica Tourist Board ( www.visitcostarica.com) and the Latin American Travel Association (020-8715 2913; www.lata.org).