Global forest plot analyses have not yet properly sampled the forests of Indonesia. That is despite the country being pound for pound the most botanically diverse on the planet.

Forty Indonesian ecologists and botanists alongside collaborators analysed tree diversity at local scales e.g. 0.25 ha to 10 ha.

What we found was that bigger wetter islands had more species locally.

Additionally, when controlling for climate, the western islands that tend to be older in age had greater tree diversity. We also found an intriguing negative effect of proximity to earthquakes that in this geologically active region could shape the ecology, evolution and biogeography of the flora.

The ms is available OA here.

We thank Badan Riset Inovasi Nasional for research permits and BKSDA for access to conservation areas.