Siamese Kauri, Ancient kauri tree in Thames-Coromandel District, New Zealand

The Siamese Kauri is a large tree in Kauri Grove, roughly 10 kilometers south of Coromandel township, where two trunks rise side by side from a shared base. Both trunks belong to a single root system and reach high into the canopy above.

The Siamese Kauri began as two separate seedlings that grew in diameter over centuries until their bases fused. Why this tree and the other kauris of Kauri Grove escaped felling, unlike almost all kauri on the Coromandel Peninsula, is unknown; one suggestion is that mining companies hoping for gold controlled the land and restricted access. During World War II the government planned to log the grove for the war effort, and residents formed one of New Zealand's first conservation groups; after much opposition the message came from the capital that "logging will cease forthwith".

The name refers to the conjoined lower trunk the two trees share, likening it to Siamese twins. The grove is also called Waiau Kauri, and it lies about 500 metres off the 309 Road, reached on a 30-minute walking track. Residents who fought the wartime logging plans formed one of New Zealand's first conservation groups.

The tree stands about 500 metres off the 309 Road, reached on foot by a walking track that takes roughly 30 minutes through Kauri Grove. The route passes other mature kauri before arriving at the fused trunks.

Two separate seedlings grew so close over the centuries that their bark actually fused together, creating one living being from two independent trees. This type of natural fusion is uncommon in kauri trees and shows how adaptable these giants can be.