Privately managed by conservation group Defensores de la Naturaleza, Sierra de Las Minas Biosphere Reserve  is a vast, 583,000-acre mountain park encompassing a diverse variety of ecosystems, including cloud forests harboring several species of endemic conifers, as well as tropical moist and rainforests.
The peaks of Sierra de las Minas surpass 3,000 meters (9,800 feet) in elevation and are home to healthy populations of quetzals and jaguars, among other exotic animals.
Sixty-two permanent streams have their source in the upper slopes of the biosphere reserve, making it an important watershed supplying the Motagua and Polochic Rivers. Together with the adjacent Bocas del Polochic Wildlife Refuge, the parks account for 80 percent of Guatemala’s biodiversity.
The four-million-acre The Maya Biosphere Reserve  is composed of Tikal National Park ,Laguna del Tigre National Park , Mirador–Río Azul National Park , Sierra del Lacandón National Park , Biotopo El Zotz–San Miguel la Palotada , Yaxhá-Nakum-Naranjo Natural Monument , and multiple-use and buffer zones.
This large swath of land encompasses roughly a third of the Petén department and is Guatemala’s last hope for preserving a sizable part of the Petén forests. Contiguous with large parks in neighboring Mexico and Belize, it is part of the largest protected tropical forest in Mesoamerica.
The various parks are protected, on paper at least, from all human activity, though a sizable multiple-use zone exists in large areas of the park, permitting sustainable extraction of forest products such as xate palm and chicle, oil drilling (present before the park’s creation), and community forestry concessions. Standing between the core zones and the deforestation characterizing much of the rest of Petén is an ever-shrinking buffer zone increasingly porous to the advance of the agricultural frontier. The individual parks making up the biosphere reserve are covered here in their respective sections.