Careful consideration is essential when determining the release area for orangutans. One of the most important factors is ensuring that the forest is productive and its natural food sources can sustain an orangutan population far into the future. 

To assess the suitability of potential areas and monitor the health of the forests we work in, our Post-Release Monitoring (PRM) teams regularly conduct phenology surveys.

Phenology surveys involve recording data monthly on marked plants along set transects. As the team follows the route, they record each plant’s phenological stage (meaning if there are young leaves, mature leaves, flower buds, blooming flowers, unripe fruits, or ripe fruits) and the abundance and coverage of each type of growth.

With this data, we track changes in development, which serve as early indicators if the ecosystem has been disturbed by changes in climate or human intervention. We can also use it to predict the fruiting seasons and plan orangutan releases accordingly.

In the Kehje Sewen Forest, we have identified hundreds of orangutan food sources, including wild fig trees (Ficus spp.), various jackfruit species (Artocarpus spp.), and several types of wild ginger shoots (Etlingera spp.).

In addition to the nearly 200 plant species we recorded on these phenology surveys, the forest is rich in alternate orangutan food sources such as termites and ants. The vast biodiversity of the Kehje Sewen Forest supports this important ecosystem as each species plays a unique role in its healthy functioning. 

When we protect our forests, they return the favour, providing us with a stable climate and plentiful resources.

Find out more about our orangutan conservation work here.

How Can You Help

There are lots of ways you can support orangutans and help ensure the survival of this precious ape.

Adopt an Orangutan

Adopt an Orangutan

Orangutans are endangered and at risk of extinction. Habitat destruction results in hundreds of orphaned orangutans, who rely on our care every year. You can help by adopting one. Their dedicated ‘nannies’ teach them everything they need to know for when it’s time to release them back to the wild. You can follow their progress through Forest School.

Adopt Now
Make a Donation

Make a Donation

Please help the Orangutans in their struggle for survival. Your donation is important and goes directly to BOS Indonesia. By donating, you are helping bring this noble yet endangered species back from the brink of extinction and on a path to freedom - from rescue to rehabilitation and release.

Donate Now
Visit Our Shop

Visit Our Shop

The perfect gift for any occasion! Choose from our selection of instant gifts that directly support our orangutans. You can buy a wheelbarrow, provide food for an orangutan for two months or lots more. You will receive a certificate, personalised with the name of your choice - perfect gift for you or a friend.

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