Rimu
A mature rimu
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Araucariales
Family: Podocarpaceae
Genus: Dacrydium
Species:
D. cupressinum
Binomial name
Dacrydium cupressinum
Natural range of D. cupressinum

Dacrydium cupressinum, commonly known as rimu, is a large evergreen coniferous tree endemic to the forests of New Zealand. It is a member of the southern conifer group, the podocarps.

The Māori name rimu comes from the Polynesian term limu which the tree's foliage were reminded of,[2] ultimately from Proto-Austronesian *limut meaning "moss".[3] The former name "red pine" has fallen out of common use.

Distribution

Rimu grows throughout New Zealand, in the North Island, South Island and Stewart Island/Rakiura.[4] This species is common in lowland and montane forest.[4] Although the largest concentration of trees is now found on the West Coast of the South Island, the biggest trees tend to be in mixed podocarp forest near Taupō (e.g., Pureora, Waihaha, and Whirinaki Forests). A typical North Island habitat is in the Hamilton Ecological District, where Fuscospora truncata and rimu form the overstory. Associate ferns on the forest floor are Blechnum discolor, Blechnum filiforme, Asplenium flaccidum and Hymenophyllum demissum.[5] An 800-year-old rimu tree can be seen at the Otari-Wilton's Bush in Wellington.[6]

Rimu foliage

Description

Rimu is a slow-growing tree, eventually attaining a height of up to 50 m, although most surviving large trees are 20 to 35 m tall. It typically appears as an emergent from mixed broadleaf temperate rainforest, although there are almost pure stands (especially on the western coast of the South Island). There are historical accounts of exceptionally tall trees, 61 m, from dense forest near National Park in the central North Island, now destroyed.[7] Its lifespan is approximately 800 to 900 years. The straight trunk of the rimu is generally 1.5 m in diameter, but may be larger in old or very tall specimens.[7]

The leaves are spirally arranged, awl-shaped, up to 7 mm long on juvenile plants, and 1 mm wide; and 2 to 3 mm long on mature trees.[7] It is dioecious, with male and female cones on separate trees; the seeds take 15 months to mature after pollination. The mature cones comprise a swollen red fleshy scale six to ten mm long bearing one (rarely two) apical seeds 4 mm long. The seeds are dispersed by birds which eat the fleshy scale and pass the seed on in their droppings; the cones are an important food resource for some species, particularly the kākāpō, whose breeding cycle has been linked to the fruiting cycle of the tree.

Rimu seed cones

Uses

Māori originally used the resinous heartwood of rimu (called māpara or kāpara) for wooden items such as heru (combs) and fernroot beaters.[8][9] Historically, rimu and other native trees such as kauri, mataī and tōtara were the main sources of wood for New Zealand, including furniture and house construction. However, many of New Zealand's original stands of rimu have been destroyed, and recent government policies forbid the felling of rimu in public forests, though allowing limited logging on private land. Pinus radiata has now replaced rimu in most industries, although rimu remains popular for the production of high quality wooden furniture. There is also limited recovery of stump and root wood, from trees felled many years before, for use in making bowls and other wood turned objects.

The inner bark can also be used to treat burns and cuts.[10]

In cultivation

Although slow to establish, with a long juvenile period and fairly high moisture requirements, rimu is widely grown as an ornamental tree in New Zealand. It is attractive at all growth stages, usually quite narrow when young, then developing into a broader tree with weeping branches before finally progressing to its more upright adult form. While rimu does exhibit some variation in the wild, garden cultivars are largely unknown, except for one recent introduction, 'Charisma', which is a compact, golden-foliaged form.

Pests and diseases

This species plays host to the New Zealand endemic beetle Agapanthida pulchella.[11]

Trunk of a rimu with descending rātā (Metrosideros) roots

References

  1. ↑ Thomas, P. (2013). "Dacrydium cupressinum". IUCN Red List of Threatened Species. 2013: e.T42448A2981038. doi:10.2305/IUCN.UK.2013-1.RLTS.T42448A2981038.en. Retrieved 19 November 2021.
  2. ↑ "Limu: mosses, seaweed and lichens". Te Māra Reo: The Language Garden. Benton Family Trust. 2022.
  3. ↑ Blust, Robert; Trussel, Stephen (2010). "*limut: moss, algae". Austronesian Comparative Dictionary. Max Planck Institute for Evolutionary Anthropology. Retrieved 7 December 2022.
  4. 1 2 Eagle, Audrey (2008). Eagle's complete trees and shrubs of New Zealand volume one. Wellington: Te Papa Press. p. 22. ISBN 9780909010089.
  5. ↑ C. Michael Hogan. 2009. Crown Fern: Blechnum discolor, Globaltwitcher.com, ed. N. Stromberg Archived February 13, 2012, at the Wayback Machine
  6. ↑ Wellington City Council. "Otari-Wilton's Bush brochure" (PDF). Wellington City Council. Archived (PDF) from the original on 14 February 2014.
  7. 1 2 3 Salmon, J.T. (1993). The Native Trees of New Zealand. Auckland, New Zealand: Reed Books. pp. 74–79.
  8. ↑ Lawrence, Joan (1990). "COMBS FROM ROCK SHELTERS IN THE WAITAKERE RANGES, WEST AUCKLAND on JSTOR". Records of the Auckland Institute and Museum. 27: 61–71. ISSN 0067-0464.
  9. ↑ Wallace, R., & Sutton, D. G. (1989). A preliminary study of wood types used in pre-European Maori wooden artefacts. Saying So Doesn’t Make It So: Papers in Honour of B. Foss Leach. Dunedin: New Zealand Archaeological Association Monograph, 17, 222-232.
  10. ↑ "Maori uses: Medicinal plants, Conifers". University of Auckland. Archived from the original on 15 October 2008. Retrieved 12 October 2008.
  11. ↑ Stephanie L. Sopow; John Bain (14 September 2017). "A checklist of New Zealand Cerambycidae (Insecta: Coleoptera), excluding Lamiinae" (PDF). New Zealand Entomologist. 40 (2): 55–71. doi:10.1080/00779962.2017.1357423. ISSN 0077-9962. Wikidata Q56166058.
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