The story of conservation at Poás began in Tennessee's Great Smoky Mountains National Park in the 1960's. Mario Boza was a student when he visited the park in the United States and was so impressed that he developed a plan to manage the area around Poás Volcano in a similar way, presented it as his masters thesis, and pursued its implementation. How the plan was adopted as an integral part of the birth and development of the National Park system in Costa Rica is described in David Rains Wallace's book.
Attractions and Amenities
Poás volcano is a powerful symbol of the geothermal forces that formed Costa Rica.
When the mist and clouds part you'll see the sulfuric, bubbling, green rain fed lake at the bottom, surrounded by smoke and steam rising from fumaroles. Water from the lake is constantly seeping through cracks in the hot rock, evaporating and building pockets of steam. When the pressure in these pockets exceeds the weight of the water above, the steam breaks through in geysers that rocket up to 820 feet (250 meters) high. Don't worry about getting a shower though, the crater is 1,050 feet (320 meters) deep. At almost a mile (1.6 km) across it's also the largest active crater in the world.
Poás is active, but don't expect to see a full fledged eruption or even any lava flow here, the most recent period of eruptive activity ended in 1954. The last major activity was in 1910 when nearly a million tons of ash was ejected along with an immense column of smoke and steam.
A modern visitors center (wheelchair accessible) and small museum explains and interprets the geothermal and ecological attractions in the park. A cafe serves coffee and hot drinks—as much to wrap your hands around to warm them as anything else—sandwiches, and snacks.
The volcano provides an excellent if extreme example of the effects of acid rain. Around the caldera, and for several miles downwind, the vegetation is stunted brown and black by the tainted moisture that precipitates from the omnipresent clouds near the peak.
Trails that lead through cloud forest stunted and twisted, not only by volcanic emissions but the rigors of the cold windy high altitude habitat. Lake Botos fills an extinct crater at the end of one trail, and is home to many cloud forest birds including hummingbirds, tanagers, flycatchers, toucanets, Costa Rica's national bird the clay-colored robin, and the area's most famous avian resident, the resplendent quetzal.
