The floor of the Jomblang sinkhole is covered in what guides call the hutan purba — the ancient or primeval forest. When the cavern roof collapsed, soil and vegetation dropped to the bottom and went on growing there, sealed off from the surface by vertical walls.
Conditions at the bottom are very different from those on top. Gunungkidul’s surface is dry limestone country, brown for half the year and planted with teak, cassava and maize. Sixty metres down, the air is cool and humid, direct sun arrives for only a short part of the day, and the result is a dense tangle of ferns, mosses, shrubs and slender trees reaching for the light. Botanists value such sinkhole forests as refuges for plants that have become scarce on the cleared plateau above.
What to see and do: The Ancient Forest
Land among the ferns
The rope sets you down on a slope at the edge of the forest. While you wait for the rest of your group, look up: the circle of sky framed by roots and hanging vines is one of the best views of the day.
Walk down through the trees
A short, steep path with steps cut into the clay leads through the vegetation to the mouth of the tunnel. It is slippery in any season; use the handline.
Notice the change
Compare the plants here — mosses on every surface, ferns, damp-loving shrubs — with the dry teak woods you drove through. It is a different climate a rope-length away.
How to get to The Ancient Forest
- Access: the forest is the landing zone of the Jomblang descent, so every visitor passes through it on the way to the tunnel and Grubug Cave.
Insider tips
- Stay on the path. The slope is unstable and the plants are the reason the place is protected.
- Do not pick or collect anything, and carry out everything you bring down.
- Mosquitoes are few compared with lowland forest, but repellent does no harm.
- The light for photographing the forest itself is best early, before the sun is overhead and the contrast becomes harsh.
Best tours & tickets for The Ancient Forest
These top-rated experiences are the easiest way to visit The Ancient Forest from Yogyakarta:
Cave tour from $22 Yogyakarta: The Jomblang Cave Adventure Trip
A well-reviewed trip focused on Jomblang alone, with transport and a meal. The driver times the departure so you are registered and geared up before the descents start, and you are usually back in Yogyakarta in the mid-afternoon.
- Door-to-door transfer from your hotel
- Guided descent, ancient forest and Grubug Cave
- A meal is included according to the listing
Cave tour from $30 Yogyakarta: Jomblang Cave Tour
A straightforward return trip to Jomblang: pickup, the drive into the karst hills, the descent, the forest, the tunnel and the light, then back to the city by mid-afternoon. It suits travellers who would rather not rush on to a second stop, or who want the afternoon free for Prambanan or a rest.
- A day built around the cave and nothing else
- Timed for the late-morning light beam
- Long-running listing with a steady 4.8 rating
Full-day adventure from $14 Yogyakarta: Jomblang & Pindul Cave Guided Adventure
A long-established alternative to the bestseller with the same shape of day: Jomblang in the morning for the light, Pindul tubing after lunch. The low starting price generally covers transport and guiding; read the listing carefully for what is and is not included, as the Jomblang entrance fee is often paid at the cave.
- Both caves with a guide and driver
- Shared or private option
- One of the lowest headline prices, with hundreds of reviews
