Bromo Tengger Semeru National Park (Indonesian: Taman Nasional Bromo Tengger Semeru; abbreviated as TNBTS) is a national park in East Java, Indonesia. It is located east of Malang, west of Lumajang, south of Pasuruan and Probolinggo, and southeast of Surabaya, the capital of East Java. It is the only place in Indonesia with a sand sea called the Tengger Sand Sea (Indonesian: Laut Pasir Tengger). This sand sea covers the caldera of an ancient volcano (Tengger), from which four new volcanic cones have formed. This unique feature spans 5,250 hectares at an altitude of about 2,100 meters (6,900 feet). The area also includes the highest mountain in Java, Mount Semeru (3,676 meters or 12,060 feet), four lakes (including the isolated Ranu Tompe), and 50 rivers. The park is named after the Tenggerese people. The volcanic eruption that created the caldera occurred about 45,000 years ago, similar to the Krakatau eruption.

The Tengger Sand Sea has been protected since 1919. Bromo Tengger Semeru National Park was officially declared a national park in 1982.

Geography

The Tengger massif is a mountainous area located within the park. This region is an active volcanic complex that is surrounded by a large plain of sand.

The Tengger volcanic complex has a unique structure where a new caldera, or large volcanic crater, forms inside an older and larger caldera. Within the Tengger Caldera, there are five volcanoes: Mount Bromo (2,329 m), Mount Batok (2,470 m), Mount Kursi (2,581 m), Mount Watangan (2,661 m), and Mount Widodaren (2,650 m). Mount Batok is no longer active and is covered with casuarina (Indonesian: cemara) trees. Mount Widodaren, which is near Mount Batok, has a cave called Widodaren, which is considered sacred by local people.

The five volcanoes inside the caldera are surrounded by a large area of sand known as the Tengger Sand Sea. This sand sea is enclosed by a steep crater wall of the larger Tengger Caldera, which has height differences of about 200–600 meters (660–1,970 ft). Other mountains near the Tengger Caldera include Mount Pananjakan (2,770 m), Mount Cemorolawang (2,227 m), Mount Lingker (2,278 m), Mount Pundak Lembu (2,635 m), Mount Jantur (2,705 m), Mount Ider-ider (2,527 m), and Mount Mungal (2,480 m). The peak of Mount Pananjakan is the most popular spot for viewing the entire Tengger volcanic complex.

Further south in the national park lies another volcanic area called the Semeru Group or Jambangan Group. This region includes Mount Semeru (3,676 m), which is the highest peak in Java. Other mountains in this area are Mount Lanang (2,313 m), Mount Ayek-ayek (2,819 m), Mount Pangonan Cilik (2,833 m), Mount Keduwung (2,334 m), Mount Jambangan (3,020 m), Mount Gentong (1,951 m), Mount Kepolo (3,035 m), and Mount Malang (2,401 m). The Semeru forest area contains many rivers that were once lava flows from Mount Semeru. This volcanic group is very productive, producing materials like lava, volcanic ash, and hot clouds that spread to surrounding areas. The lower regions are covered with fertile rice fields.

The climate in the Bromo Tengger Semeru area is cold, especially during winter, which runs from May to September. Heavy rainfall occurs in summer, while winter has little to no rain. Winter nighttime temperatures often drop below zero degrees Celsius, with possible frost and light snow. This region has a subtropical highland climate.

Ecosystem

The forests in this area can be divided into three zones based on differences in height and temperature.

This area is called a tropical rainforest. It is located in the southern part of Semeru, as well as in East Semeru (Burno) and West Semeru (Patok Picis). The plants in this zone mainly belong to the families Fagaceae, Moraceae, Anacardiaceae, Sterculiaceae, and Rubiaceae. Liana trees, such as those from the genera Calamus, Piper, Asplenium, and Begonia, are also present. Other plants in this area include species from the families Araceae, Poaceae, and Zingiberaceae. There are 225 species of orchid found here.

Plant life is much less common in this area. Many of the plants that grow here are pioneer species. Some wooden plants include cemara (Casuarina junghuhniana), mentinggi gunung (Vaccinium varingifolium), kemlandingan gunung (Albizia lophantha), acacia bark (Acacia decurrens), and bottom plants such as Javanese edelweiss (Anaphalis longifongila and Anaphalis javanica), Imperata cylindrica, Pteris sp., Themeda sp., and Centella asiatica.

The Tengger Sand Sea in the Tengger Caldera is a unique ecosystem. This area is covered with sand from volcanic activity at Mount Bromo. It is considered the only known desert-like area in Indonesia. The Tengger Sand Sea has been protected since 1919.

The plants found in this area include mentinggi gunung (Vaccinium varingifolium) and cemara (Casuarina junghuhniana). Kemlandingan gunung (Albizia lophantha) and Javanese edelweiss also grow here.

Above an altitude of 3,100 meters on Mount Semeru, there is no plant life. This zone is covered with loose sandstones.

Flora and fauna

This park protects many endangered plants, including the families Fagaceae, Moraceae, and Sterculiaceae, as well as the species Casuarina junghuhniana, Javanese edelweiss, and about 200 types of orchids that are found only in this area.

The park has a limited variety of animals. It is home to about 137 bird species, 22 mammal species, and 4 reptile species. Examples include besra, green peafowl, Javan rusa, Sumatran dhole, crab-eating macaque, marbled cat, and Javan leopard.

Culture

The area around the park is home to the Tengger people, one of the few large Hindu groups still living on the island of Java. About 600,000 Tengger people live in thirty villages located in the Tengger mountains, including Mount Bromo and parts of the park. Their religious beliefs are based on traditions from the Majapahit period and are similar to those of people on Bali, but they include more beliefs about spirits and nature. The Tengger people are thought to be descendants of the Majapahit empire. In the 19th century, they were forced to move to the hills after a large number of Muslim Madurese people arrived in the area.

Gallery

• Sunrise at Gunung Bromo
• Tengger Caldera at sunrise
• Golden hour lighting in the park
• Long exposure photography capturing the park's landscape
• Tengger Caldera at night, with the Milky Way visible in the sky
• Tengger Caldera sunrise during a foggy morning
• Sunrise over Mount Penanjakan, a mountain near the Tengger massif
• Sunrise over Tengger Caldera on a clear day