Yakas Kauri was considered the 7th largest kauri tree [ranked by merchantable volume] in New Zealand in 1971. Nicholas Yakas became witness to many marvels of the Waipoua Forest whilst he was a young man and hot in the pursuit of Kauri gum in the 1920's. It wasn’t until 1966 when Yakas was asked if he knew of other Kauri trees in the Waipoua Forest that were as big as or larger than Tane Mahuta and Te Matua Ngahere, that he decided to share some of his secrets.

So, a group consisting of Yakas, Tudor Collins of Warkworth, (one of New Zealand’s top photographers of native bush scenery of that era), Sir Alfred Reed a publisher and author and a bush-lover, and Mrs. Ellen Wech set out and rediscovered the kauri tree. It was in 1968 when the name “Yakas Kauri” was officially accepted by the general public when Tudor Collins had one of his coloured photos of the tree published in a full page display in the weekly news of July 29 1968 edition. It was simply captioned “Yakas” tree by J.G. Erne Adams, the editor of the article, and the name has since stuck [1,2].

The often quoted height (43.9 m) volume (134.2 m3) and diameter (391.2 cm) of Yakas is taken from Burstall and Sale's 1984 book 'Great Trees of New Zealand [3]. The calculations were made using forestry methodology of the time and were sourced from a 1971 New Zealand Forest Service survey of 13 (and later 20) named kauri in Waipoua and Omahuta Forests [4]. The volumes established for each tree were of merchantable timber volumes inside bark. The 2009 measurements quoted on this record are taken from visiting U.S.A. tree researcher Robert Van Pelt's calculations where he used very accurate laser based technology and tree measurement methodology [5].
(Cadwallader 2011)

Recently available online copies of Leonard Cockayne's 1907/1908 botanical survey [6] include a photograph of a large tree he measured at 46 ft in girth, 6 ft above the ground. This tree, the largest he saw in his survey, was confused with the "phantom tree", a large tree glimpsed by hunters in the early 1960’s, and a number of expeditions by Yakas, Collins, Peter Mathews and others during the late 1960's and 1970's to locate the tree resulted in the discovery of the 'Cockayne Kauri' (Mathews took this to be the so-called phantom tree) and the re-discovery of the McGregor Kauri[2]. More recently, in 1990, Stephen King found and measured the “Phantom Kauri”[7,8], equal in volume to Te Matua Ngahere (NR/0802).

A comparison of the distribution of the burls visible in the Cockayne photograph to burls on one side of the Yakas tree show that it is the same tree. The location of the Cockayne kauri, given by him as "between Kohura and Omaia...", two clearings within the forest, south of the current day Te Matua Ngahere track. The given location for the Cockayne tree is the same as the setting of the Yakas tree. It is now known that the Yakas tree was seen, measured and photographed by Cockayne some 12 or 13 years before Nick Yakas found the tree.

(Smillie, 2016)

References:
1) Department of Conservation, Yakas Kauri Walk track notes.
2) J.G. Erne Adams, Kauri, a King Among Kings, 1990
3) Burstall S.W. & Sale E.V. 'Great Trees of New Zealand' 1984
4) Burstall, S.W. NZFS, Forest Research Institute, 'Mensuration Report No. 16, 1971 (unpublished)'
5) Robert Van Pelt 2002 & 2009 NZ Summary spreadsheet.
6) L. Cockayne, Report on a Botanical Survey of the Waipoua Kauri Forest, 1908
7) G. Ell, King Kauri, 1996, pp134-135
8) S. King (personal communication, June 2016).