The Río Bío-Bío is born out of Lake Gualletue east of Temuco. Much of the upper river valley is protected in a series of preserves from the Ralco hydroelectric power plant southward, featuring beautiful araucaria forests and plenty of places to stay, including several spas. Three volcanoes -- Tolhuaca, Lonquimay, and Llaima -- dominate the landscape.

The Alerce & the Araucaria: Living National Monuments

The Lake District and its neighboring forests in Argentina are home to two of the oldest trees on the planet: the alerce and the araucaria, otherwise known as larch and monkey puzzle trees, respectively. The alerce is a sequoialike giant that grows less than 1 millimeter each year and can live for more than 3,000 years, making it the world's second-oldest tree after the California bristlecone pine. They are best viewed in the Alerce Andino National Park and Pumalín Park.

The araucaria, called pehuén by the Mapuche, is unmistakable for its gangly branches and thick, thorny leaves that feel waxy to the touch. Mature trees can grow as high as 50m (164 ft.) and take on the appearance of an umbrella, which is why they're often called Los Paraguas (the Umbrellas). They do not reach reproductive maturity until they are about 200 years old, and they can live as long as 1,250 years. They are best seen in Tolhuaca, Villarrica, and Conguillío national parks, but they're virtually everywhere around the Lake District. The araucaria seed (piñón), an edible nut, was a principal source of food for the Mapuche; later the tree was coveted for its quality wood, and, as with the alerce, aggressive harvesting destroyed the majority of its forests. Today both the alerce and the araucaria have been declared protected national monuments.

Conguillio National Park

One of Chile's finest national parks, Parque Nacional Conguillío surrounds the spectacular smoking cone of Volcán Llaima and features a dense forest of spindly araucaria trees, which the park was created to protect. It's a lovely park and a great attraction year-round due to several splendid hiking trails, a ski resort, and an outstanding park information center. Volcán Llaima is one of the most active volcanoes on Earth and has registered 40 eruptions since 1640, most recently in April 2009. In the southern section of the park, it is also possible to witness the tremendous destruction lava has wreaked on the surrounding forest. Conguillío is divided into three separate sectors with as many access points. The western side of the park is commonly known as Los Paraguas (the Umbrellas); the eastern side is accessed from the north in Sector Laguna Captrén, and the south at Sector Truful-Truful. Visitors will find the park's administration center, campgrounds, and most hiking trails here in the eastern sector.

The eastern access point is at the village Cherquenco; from here a 21km (13-mile) rutted road ends at the Centro de Esquí Las Araucarias (tel. 45/274141; www.skiaraucarias.cl) in Los Paraguas. Las Araucarias is not well-known, and its four T-bars are tiresome, but if you are a ski buff and are in the area, this little resort is worth the visit for its surrounding forest of araucaria and simply breathtaking views. (The road here is in bad shape, so bring a vehicle with chains and high clearance.) The center also has a ski school, equipment rental, and a restaurant and bar. Ticket prices are $30 (£20) Monday through Friday and $34 (£23) on weekends. The center offers dormitory-style lodging in two single-sex rooms with about 10 to 15 bunk beds without bedding for $11 (£7.30) per person (and two dormitories for 10 to 11 people for $17/£11 per person). Other lodging options are the Apart Hotel Llaima (five apartments with four beds each; $115/£77 a night), Refugio Pehuén (three units; $25-$30/£17-£20 double), and the Refugio Los Paraguas (one unit, six beds; $120/£80). Check www.skiaraucarias.cl for reservations.

An unpaved and poorly maintained road connects a Conaf (park service) visitor center, which is open daily from 9am to 1pm and 3 to 7pm (tel. 45/298213), with the towns Curacautín in the north and Melipeuco in the south. The information center has interpretive displays highlighting the park's flora, fauna, and physical geology, including an interesting section devoted to volcanism. During the summer, park rangers offer informative talks and walks and a host of educational activities, which they post in the visitor center. (English-language talks can sometimes be arranged; send an e-mail to info@parquenacionalconguillio.cl, or check directly at the center.)

There's an easy, hour-long, self-guided trail that leaves from the Conaf center, but if you really want to get out and walk, you'll want to take the Sierra Nevada trail. This moderate 5-hour hike is the best in the park, taking visitors through thick forest and rising to two lookout points that offer sensational volcano and lake views before dropping back down to the Captrén Lagoon near the Conaf center. The trail head is on the western shore of Lake Conguillío, at the Conaf center. A second 5-hour hike along moderate terrain, Los Carpinteros, weaves its way through stands of araucaria trees that are several hundred -- some more than 1,000 -- years old. This trail leaves from Laguna Captrén at the Conaf center.

Getting There & Basics -- If you plan to rent a vehicle, try to get one with a high clearance -- it's not essential, but it helps. Most tour companies in Temuco plan excursions to this park. Bus service from Temuco's main terminal is available only to Curacautín and Melipeuco; from here you'll need to take a taxi or hitch a ride. The road is paved only to the park entrance, so during the winter, you'll usually need a 4*4 or tire chains to get to the ski center.

The park is officially open daily April through November from 8am to 11pm, and May through October 8:30am to 5pm -- but you can really enter at any time of the day. In winter, the road through its eastern part isn't cleared, but it remains accessible -- definitely take winter gear. The summer park entrance fee is $6 (£4) for adults and $2 (£1.30) for children (free for those under 12 years). There are a cafeteria and a store at Conaf's park information center in front of Lake Conguillío.

Corralco Ski Resort

This small resort (with one chairlift and one T-bar) in the Malalcahuello National Preserve is a good option for beginners and more of a novelty for experts. The eight runs on Lonquimay Volcano's treeless slope are relatively short and none tougher than intermediate level, so you might well long for a lift extending higher up toward the summit. But there are some off-piste possibilities and a few steep drops for snowboarders. It also has great views of the Llaima Volcano and the Andes along the border with Argentina, beyond the araucaria forest. Line up early or pack a lunch as the cafeteria is easily overwhelmed even on normal days. Lift fees are $40 (£27) per adult; $33 (£22) for seniors and children 11 and under. The hotel, however, has six fine rooms paneled in light wood amid the araucarias. Doubles with half-board are $168 (£84) per person Monday through Thursday and $214 (£143) Friday through Sunday (tel. 2/202-9326; www.corralco.com). To get there, turn left 4km (6 miles) after passing the village of Malalcahuello on Rte. 181, continuing for another 4km (6 miles), then turn left again on the forest road.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.