Volcán Poás is one of the seven active volcanos in Costa Rica and is part of the western end of the Cordillera Central. It takes the form of a flattened dome with two eones rising aboye the massif, reaching a height of 2,708 m. The park includes most of the volcano above 2,350 m in which there are three main geographical features:

The active crater-is 300 metres deep with perpendicular stratified walls and a small laguna at the bottom. Volcanic activity has been continuous, with periodic geyser type eruptions and continual escape of gases. Eruptions occasionally are of considerable size and duration and ash is deposited over a wide area, as occurred in 1952.
The bare eroded area to the west and to the northeast of the crater– the vegetation has been destroyed by volcanic activity and deep gullies have formed in the unprotected ground.

The old craters-the walls of which are still clearly visible. The oldest is probably that which now contains the “laguna”-a shallow lake 8 m deep.

The climate is characterised by a heavy rainfall of 3,700 mm a year,
and high humidity. Rainfall occurs throughout the year, particularly from May
to October with a drier period from December to April, with many rain free
days. There is little annual variation in temperature, which ranges from 9 to
13 e, although the daily fluctuations are much greater.

Much of the park is covered with forest vegetation except where destroyed
by volcanic eruptions, clearance' for pastures or by logging. activities. The term
“cloud forest” is often used to describe the vegetation of this altitude, ' a term
derived from the fact that, as air blowing from the Atlantic rises over the
mountains, condensation occurs and clouds cover much of the land over 2,000m.

The park has a great diversity of fauna, particularly its rich bird species wildlife
with 79 bird species recorded. Some of the species noted are: sooty robin, hummingbirds, quetzal, Rufous-collared sparrow, and Yellow-thighed finch. There have also been a number of mammals identified like shrews, weasels, porcupines, rabbits, squirrels, as well as common flora species like Poor man’s umbrella (gunnera insignis), tree-shaped ferns, and bromeliads, among others.