Chatham Island Christmas tree  (Brachyglottis huntii)

Classified as Vulnerable (VU) on the IUCN Red List 2006 (1).

Voted New Zealand’s most popular native plant (3), this spectacular species is a small, aromatic tree with clusters of brilliant yellow flowers in summer (2) (4). The bark is flaky (4) and the leaves are densely clad in downy hairs, giving the whole plant a silvery hue (2).

Endemic to the Chatham Islands, New Zealand (1), including both Chatham Island and Pitt Island (4).

Found in forests, shrubland, drier swamps and along ridge crests, preferring frequently disturbed habitats such as those found along stream and river sides (2) (4). This tree typically grows on moist, peat soils, and cannot tolerate long periods of drought or heavy shade (4).

The Chatham Island Christmas tree is an opportunistic plant adapted for rapid colonisation of sites frequently disturbed by natural events such as gales, erosion events, floods and fires (2). Thus, in ideal conditions this species is fast growing and will flower within one to two years from seed (4). The beautiful yellow flowers blossom from November to February (austral summer), while the seeds mature in late summer and early autumn (2) (4).

The Chatham Island Christmas tree was formerly more common and widespread on Chatham Island, but has experienced serious declines over the past century. By contrast, this species is still fairly widespread on Pitt Island, and even expanding where stock and feral animals are rare, but diminishing elsewhere (4). A myriad of threats are believed to have impacted the tree, including destruction of its forest habitat type and browsing and trampling by cattle, sheep, pigs and possums (1) (4). Worryingly, there have been recent reports of sudden collapses and die-back of apparently healthy trees, speculated to be the result of soil borne pathogens such as Phytophora and Verticillium wilt. In addition, propagated seeds collected from isolated trees have shown very poor germination, suggesting that the species is self-incompatible. This is of particular concern on Chatham Island, where parts of the island are now represented by isolated individuals, and has important implications for future management (4).

The Chatham Island Christmas tree occurs in Pitt Island Scenic Reserve (2). More research is urgently needed into the mysterious die-back of several specimens, before appropriate conservation measures can be implemented to protect this stunning tree (5), New Zealand’s most popular native plant (3).

For more information on the Chatham Island Christmas tree see:

• New Zealand Plant Conservation Network:
  http://nzpcn.org.nz/flora_details.asp?ID=52
• Department for Conservation: Native plants:
  http://www.doc.govt.nz/templates/page.aspx?id=33542