Biological Flora of New Zealand 17: Kunzea ericoides (Myrtaceae), Kānuka

Abstract

This review summarises the taxonomic status, morphology, physiology, ecology, plant communities, mycological, invertebrate and vertebrate interactions and human use of the New Zealand endemic tree Kunzea ericoides (A. Rich.) Joy Thomps. (kānuka) (Myrtaceae). While first treated as two species and later divided into ten species, recent comprehensive genetic analysis has shown that it is a single variable species. Kānuka ranges in size from small, multi‐stemmed trees about 4 m tall to one of the tallest angiosperms at over 30 m. It is a relatively long‐lived successional tree, tolerant of winter cold and drought and a wide range of soils. It is one of the few native trees that regenerates widely after fire and is abundant throughout most of New Zealand, including many northern islands. Its original disturbance‐related niche has greatly expanded as a result of deforestation since human settlement. We now live in the golden age of kānuka; it is probably more widespread and abundant now than it has ever been in the past. Kānuka tends to form monospecific stands through which other tree species regenerate, but this is dependent on climate and seed sources. Kānuka forests harbour a diverse mycological and invertebrate biota. Abundant flowering, seeding and invertebrate populations make it a highly suitable habitat for birds and reptiles. Once treated largely as a weed in agricultural landscapes or used for firewood, recent years have seen it increasingly valued for honey and essential oil production. Kānuka has also become pivotal to restoration projects through its ease of nursery propagation, rapid growth and canopy closure and tolerance of a wide range of situations, including vertebrate browsing. These same attributes make it a favoured Indigenous species for erosion‐control, especially on steeplands.