the waterfall which have been covered in moss. During the rainy season, when the waterfall is active, the water and the light change the colors of the “branches” and make the formation stand out. The park was a candidate in 2009 as one of the Seven New Natural Wonders of the World. Climate Despite its biological, ecological and cultural diversity, there have been few studies performed in the park area. For this reason, there is a lack of information about species, habitats and water flow. There is also relatively little information about how human activities affect the park. As the park is located in the Central Valley of Chiapas and borders the Northern Mountains region, altitudes vary from approximately above sea level in the municipality of Chiapa de Corzo to above sea level at the El Roblar lookout point. This geography produces a channel for air flow from northwest to southeast as well as three main climates based on the Köeppen system as modified for Mexico. These are hot and dry (where airflow is blocked), semi-hot and humid, and hot and humid. The average rainfall for the park is about 1,000 mm during the rainy season from May to October and 200 mm during the dry season from November to April. Average annual temperature is 26 °C. The rugged terrain also forms a number of microclimates. Vegetation Most of the park's vegetation, especially around the canyon, is dense tropical rainforest. Most species found in the park are members of the family Fabaceae with 59 species and the family Asteraceae with 25 species, which reflect the abundance of these families statewide. Other important families include the Orchidaceae and Euphorbiaceae, each with 22 species, the family Convolvulaceae with 17 species, and the Cactaceae with 11 species. 122 species are considered valuable as ornamental plants with 46 having medicinal uses and 31 species valuable for logging. These mostly come from the rainforest areas. The rainforest vegetation is mostly deciduous, shedding leaves in the dry season. However, there are perennial rainforests, forests of pine and oak, grasslands (mostly induced) and areas with secondary vegetation. The three main vegetation classifications are low-height rainforest, medium-height rainforest (as per the size of the trees), pine-oak forest and meadows. Medium-height deciduous rainforest is mostly located on either side of the canyon, in the north and east of the part towards San Fernando and in the Cañada Muñiz at