Have you ever seen a fruit that looks like a rambutan, but isn’t?
Saninten, a forest fruit that once grew across Indonesia’s forests, is now increasingly rare. This tree, scientifically known as Castanopsis argentea, is endemic to Indonesia and can grow up to 40 meters. In some places, it is also called Berangan or Sarangan. Today, Saninten is considered a rare species and has been listed as endangered by the IUCN (International Union for Conservation of Nature).
One of the most fascinating things about Saninten is its fruit. From a distance, you could be misled. The fruit resembles a rambutan with its spiky shell. But when touched, the difference becomes clear: Saninten’s spikes are hard and sharp, not soft. You can’t just pick it up carelessly. Inside the spiky husk are three reddish-brown seeds that are edible. The taste? Sweet, nutty, and tender — similar to chestnuts. That’s why Saninten is often referred to as Sweet Chestnut in English.
Source: KSDAE
Interestingly, in the foothills of Mount Ciremai, local folklore says that Saninten has a “partner tree” known as Pasang (Artocarpus sp.). In these stories, Pasang is considered Saninten’s “husband,” and their coexistence is believed to be essential for Saninten’s fruiting success. They are often found growing side by side, complementing one another. Communities that live near the forest frequently consume Saninten seeds as a snack. The seeds were typically boiled, roasted, or grilled until the spines softened, and then the kernels were eaten. Its unique flavor made it a favorite in several mountain villages.
But it’s not just the fruit that is special. Saninten leaves also have a distinctive characteristic: they are long and pointed, grow alternately, and when folded, a white line appears on the upper part of the leaf, a unique trait that distinguishes it from other forest trees. Meanwhile, the trunk is dark brown to black with a rough, cracked surface.
Unfortunately, Saninten trees are now increasingly rare. Many of the forest habitats have been converted into palm oil plantations or development areas. In some places, Saninten is even believed to be locally extinct. In fact, in addition to its edible fruit, Saninten’s wood from this tree is strong and durable, making it valuable for construction and furniture, which is another reason for its decline.
The story of Saninten is not just about a tree, but also about natural heritage and local knowledge that is slowly being forgotten. If conservation efforts aren’t taken seriously, future generations might also simply realize Saninten through stories, now no longer from direct experience.
In addition to having a distinctive shape and a rich history, Saninten fruit has a unique reproductive cycle that makes conservation very difficult. The tree normally starts blossoming between August and October. The male flowers grow in long, grain-like clusters that are 15 to 25 cm long. The female flowers grow on their own and are shorter, about 5 to 15 cm. Both are a mild yellowish-white color, which makes Saninten trees look beautiful in the spring when they are in flower.
Unlike many other plants that fruit annually, Saninten only produces fruit once every two years, between November and February. Even in years when it does bear fruit annually, the second-year fruits are often empty and fail to produce viable seeds. This long fruiting cycle makes natural Saninten regeneration difficult.
Adding to the challenge, Saninten fruits are a favorite food for wildlife, especially birds and mammals. As a result, even when a tree does produce fruit, many of the seeds are eaten before they have a chance to grow into new trees. Naturally occurring seedlings of Saninten are extremely rare. This is one of the main reasons why Saninten is now included in Indonesia’s list of protected plants. Under Regulation of the Ministry of Environment and Forestry (KLHK) Number 92 of 2018, Saninten is officially designated as a species that must be protected, both within forested areas and beyond.
There is a purpose for this protection. Saninten is in danger of dying out because it doesn’t regenerate quickly enough, loses its habitat, and is overexploited.
Saninten Conservation: Protecting What Remains, Planting for the Future
Source: dokumentasi Seasoldier – pembibitan di Taman Buru Gunung Masigit Kareumbi, Jawa Barat
Due to its growing rarity, conservation of Saninten trees has become an urgent priority and cannot be delayed. Today, you may still see Saninten in several protected forests and conservation areas, like Gunung Gede Pangrango National Park and Gunung Halimun Salak National Park in West Java. These areas serve as the last bastion for the survival of Saninten in its natural habitat, which has been heavily degraded elsewhere. Saninten grows in Sumatra, Kalimantan, and Java, but it is most common throughout hilly and mountainous areas between 150 and 1,750 meters above sea level. The Saninten tree grows best in a cool area with moist soil and a lot of trees.
Since its natural habitat (in-situ conservation) is shrinking, conservation efforts are now being expanded beyond its natural habitat, known as ex-situ conservation. This includes cultivating Saninten in forest plantations and agroforestry systems. One approach is ex-situ genetic conservation (plasma nutfah), which ensures that the species’ genetic resources are preserved in case its natural populations vanish completely.
In addition to its ecological value, Saninten also has economic and cultural potential. Its nutty seeds could be turned into local treats, culinary items, or even valuable goods. Therefore, protecting Saninten is not only a conservation issue, but also an opportunity to support food security based on local resources.
Source: dokumentasi Seasoldier – pembibitan di Taman Buru Gunung Masigit Kareumbi, Jawa Barat
Despite these efforts, a major knowledge gap remains. Research on Saninten’s ecology, seed dispersal, wildlife interactions, and genetic resilience to climate change remains very limited. Designing effective and long-lasting conservation plans will be hard without this information. Saninten is more than just a fruit that people have forgotten about in the jungle. It stands for Indonesia’s biodiversity, cultural legacy, and potential for food security. Protecting Saninten means protecting a living legacy that connects ecosystems, wildlife, and local communities.
With ongoing conservation efforts and expanded research, Saninten could be restored not only as a rare species but also as a symbol of Indonesia’s sustainable future.
Writer: Novi Wiji Lestari
Editor: Diyah Deviyanti
Reference:
- Direktorat Jenderal KSDAE. (2018, September 30). Saninten Riwayatmu Kini. Direktorat Jenderal Konservasi Sumber Daya Alam dan Ekosistem, Kementerian Lingkungan Hidup dan Kehutanan. Retrieved September 23, 2025, from https://ksdae.or.id/berita/4674/Saninten-Riwayatmu-Kini.html
- Heriyanto, N. M. (2007). Kajian ekologi permudaan Saninten (Castanopsis argentea (Bl.) A.DC.) di Taman Nasional Gunung Gede Pangrango. Neliti. https://www.neliti.com/publications/54520/kajian-ekologi-permudaan-saninten-castanopsis-argentea-bl-a-dc-di-taman-nasional
- Hilwan, I., & Irfani, E. (2018). Pola Penyebaran Dan Regenerasi Jenis Saninten (Castanopsis argentea Blume) Di Resort Selabintana, Taman Nasional Gunung Gede Pangrango. Journal of Tropical Silviculture, 9(1), 53–59. https://journal.ipb.ac.id/jsilvik/article/view/21306/14564
- IUCN. (n.d.). Castanopsis argentea. The IUCN Red List of Threatened Species. Retrieved September 23, 2025, from https://www.iucnredlist.org/species/62004506/62004510
- Sawitri, R., Heriyanto, N. M., Dharmawan, I. W. S., Kwatrina, R. T., Gunawan, H., Garsetiasih, R., Takandjandji, M., Rianti, A., Sihombing, V. S., Mindawati, N., Pratiwi, T., Kalima, T., Marsandi, F., Wardani, M., Denny, & Dodo. (2025). Ecological dynamics of forest stands with Castanopsis argentea (Blume) A.DC. in a mountain ecosystem: Vegetation structure, diversity, and carbon stock under tourism pressure. Land, 14(6), 1187. https://doi.org/10.3390/land14061187/1187
- Wikipedia contributors. (2025). Saninten. In Wikipedia. Retrieved September 23, 2025, from https://id.wikipedia.org/wiki/Saninten
Photos:
- KSDAE. (2018, September 30). Saninten Riwayatmu Kini [Photograph]. Direktorat Jenderal Konservasi Sumber Daya Alam dan Ekosistem, Kementerian Lingkungan Hidup dan Kehutanan. Retrieved September 23, 2025, from https://ksdae.or.id/berita/4674/Saninten-Riwayatmu-Kini.html
- Seasoldier’s personal documentation