Costa Rica's incredible biodiversity has a fascinating volcanic origin, which has led to the creation of some of the most fertile lands in the world. This tiny isthmus is a vulcanologist's paradise — part of the "Pacific Rim of Fire," Costa Rica possesses some of the most studied and visited volcanoes on the planet.
Names like Arenal, Poás, Rincón de la Vieja and Irazú are internationally recognized as symbols of the country's volcanic history. A staple stop on almost any tour is the world-renowned Poás Volcano National Park, jewel of the Central Volcanic Range Conservation Area. Created in 1971, the park's more than 16,000 acres are one of the most popular destinations0 in the country, with hundreds of thousands of visitors each year.
The scenic drive to the park winds through the province of Alajuela and its coffee-covered rolling hills. Here, coffee is grown at an elevation of 3,000 to 5,000 feet high, accounting for some of the country's best. Poás is one of the few active volcanoes in the Americas accessible by road all the way to its craters. From San José, it's a little over one hour to reach its peak, making it perfect for a day tour that can be combined with other northwestern Central Valley attractions.
At almost 9,000 feet in elevation and with temperatures averaging 40-50°F, this mountain park encompasses four different habitats and several forest types. The dramatic altitude changes seen on the way to the crater make for a spectacular variety of ecosystems and microclimates. Poás is also famous for its strange dwarf or "elfin" forest - located atop the crater and around the visitor's center - where thousands of years of exposure to acid rain, fumaroles and strong winds have given rise to perennial blooming shrubs with extremely tough stems and leaves, contrasted by delicate flowers of brilliant colors.
The half-mile boulevard between the parking area and the main crater overlook is surrounded by the plant referred to as "poor man's umbrella," typical of Costa Rica's sub-paramo flora and believed to be used by the local Poa Indians to indeed — cover themselves from the rain. The impressive main crater one of the world's largest is a gigantic cauldron almost one mile across and 1,000 feet deep with a teal-tinted sulphuric acid-filled lake (about 900 feet in diameter) at the bottom.
Fumaroles and geyser-like activity are a frequent sight, and various gasses are spewed to the air, transporting visitors to an alíen landscape of rock, ash, and not entirely pleasant scents. In fact, Poás' geyser-like eruptions of muddy water and steam have given it the reputation as the world's largest geyser, though the many studies performed here by experts strongly refute this idea. Usually, patience is needed to observe the main crater, since it is often shrouded in clouds with only momentary glimpses provided to those late arrivals who wait for a peek into the crater.
The volcano has been active for over 11 million years and has undergone periods of increased activity, first recorded in the mid-1700s by Spanish governor Juan Gemir. A major eruption occurred in 1910 when the volcano sent 640,000 tons of ash over the Central Valley for several days at a time; between 1952-1954, Poás bombarded nearby areas with ash and rocks on a regular basis. During 1989, volcanic activity forced the park's closure for several months due to the high levels of toxic acid rain emitted from the crater. Local agriculture felt the volcano's wrath, with entire croes of coffee and flowers destroyed.
Now, the spectacular main crater is a bubbling and steaming subject of study by many international organizations and does not pose an imminent threat. Activity has increased, however, and in the past weeks, seismic phenomena have been reported. In fact, the epicenter of a recent tremor was located in the town of Vara Blanca, just few miles east of the park on the way to Poás' adjacent "dormant" sister, Barva Volcano.
Poás is a semi-conical volcano, with several cauldrons at the top. Nine craters have been identified throughout the park, including the famous Botos Lake, an ancient crater filled with highly acidic jade-green rainwater and surrounded by walls of cloud forest. The lake exits the crater vía the Río Angel, plummeting down the Caribbean slope to form breathtaking waterfalls, such as La Paz Waterfall, the country's most photographed cascada. The waters later merge with the Sarapiquí River as they flow into the northern plains, giving rise to incredible whitewater rafting and wildlife observation opportunities. On the Caribbean slope of the park (the volcano's northern flank), the forest become taller, humidity increases, and ferns, palms and epiphytes begin to appear. Bromeliads, mosses, lichens and orchids abound, adding color to the forest.
In general, the fauna at Poás Volcano National Park is scarce, with only a few representative small mammals such as the elusive coyotes, long-tailed weasels, skunks and some small felines. The friendly yellowgreen squirrel, easily spotted among the trails, is endemic to Poás. With oven 79 species reported, bird watching, on the other hand, is some of the best in Costa Rica. Resplendent quetzals, black turkeys, owls, tanagers and many species of hummingbirds are all present here, including the fiery-throated and magnificent hummingbirds, as well as the scintillate hummingbird — one of the world's smallest birds at only two inches tall. Aleo present, Costa Rica's national bird, the yigüirro, or clay-colored robin, at first glance seems a common, almost unattractive bird, until its exquisite array of courtship songs fills the air.
La Escalonia trail gives visitors a closer look at the park's montane cloud forest and plants such the escalonia, a tree with a pagoda-like shape that usually marks the frost line in Costa Rica; the endemic Poás magnolia is also abundant. For the more adventurous, new trails open to the public descend from Botos Lake to the Escalonia trail, passing through the highest sections of the park and offering some of the best views. Poás Volcano's visitor center is located near the main parking lot, and features several displays of the park's history, such as old seismographs and photos, as well as some interactive learning exhibits involving the flora and fauna.
A cafetería and a souvenir shop are located on the second floor, where many park-related items are available for purchase (though prices are higher than you might pay in San José area souvenir shops). The best time to visit the park is between the dry season months of December through May, though visibility is good even during rainy season if you arrive before 9:00 a.m. to avoid the imminent cloud cover later in the morning. Poás Volcano National Park is open daily from 8:00 a.m. to 3:30 p.m., leaving plenty of time for indulging in flowers, fresh strawberries, cheese and warm coffee from roadside stands and cafés.
Park entrance is $7 for foreign visitors, ¢400 for citizens and residence. Busses to Poás Volcano National Park leave the TUASA bus station in front of La Merced Park, San José (located on 2nd Avenue between 12th and 14th Streets), at 8:30 a.m., returning at 2:00. The ride is approximately 90 minutes and coste about $2. The Travel Services Division of Costa Rica Outdoors can arrange a full day trip to Poás with transportation, including stops at other arca attractions such as the Butterfly Farm, La Paz Waterfall Gardens, Sarchí souvenir shopping and oxcart factory tour, and coffee plantation tours.
