>> FACTSHEET 6 - KAHIKATEA FOREST FRAGMENTS [PDF, 1.9 MB]

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The kahikatea (white pine) is New Zealand’s tallest tree, growing up to 60 metres - although some have been measured at 90 metres. Kahikatea stands grow on fertile floodplains, lake margins and riverbanks throughout the Waikato region and elsewhere in New Zealand. In the almost totally deforested Waikato lowlands, even small patches of kahikatea are a distinctive and iconic feature, and it’s important that we look after them.

Kahikatea then

Before humans arrived in the Waikato, pure kahikatea forest grew on the wet areas beside our lakes and swamps. Kahikatea also covered extensive areas on the great floodplains of the Waikato, Waipa, Piako and Waihou rivers. The river channels often changed their course, destroying existing vegetation and exposing new areas for kahikatea to grow on. As sites became drier, other trees such as totara, matai, rimu and hardwoods like tawa replaced the pure kahikatea forests.

With Maori settlement, the forested landscape was changed as areas were burnt off and cleared to grow food. When European settlers arrived in the 1860s, the lowlands were mostly covered by bracken and manuka between large expanses of swamp and bog. However, even back then there were still tens of thousands of hectares of kahikatea forest in the Waikato lowlands. The settlers cleared much of it, felling the trees to make butter boxes, and converting the land to fertile pasture.

Kahikatea now

There are still a few old-growth remnants of kahikatea left in the Waikato (for example, at Mangapu and Mokau).

However, most kahikatea stands in the Waikato lowlands are relatively young forest fragments, about 80-100 years old. These fragments have grown up around a few old trees left standing after most of the original forest was cleared for farming. Some stands still have their original seed trees around which the new forest grew. These massive trees, with trunks occasionally over 2 m across, are about 400-500 years old.

There are about 3060 kahikatea fragments in the Waikato region, totalling 2760 hectares. Today they are typically small, under 35 ha, with half of them less than 5 ha. Most of them grow on the river floodplains of the Waikato Basin, Hauraki Plains and Mokau River.

Because we now control flood events and re-sow flood-damaged pasture, we are unlikely to see many new areas of kahikatea forest developing in the Waikato. Scientists estimate that more than 98 of percent of the pre-European kahikatea forest has been lost nationwide.

Check out our native vegetation indicator, and find out where you can visit kahikatea stands in the Waikato region. See our map of existing kahikatea stands and of the kahikatea forest types that once would have been in your area.

Threats to kahikatea

Kahikatea forest fragments are special places with special needs. Because they tend to grow on flat, fertile sites ideal for farmland, they are often at risk of being cleared. Only 15% of the kahikatea fragments are legally protected, and only half of them are fully fenced off from stock.

Kahikatea stands are also threatened by weeds, animal pests, edge effects and isolation. Without management, the health of our kahikatea stands will gradually decline and the trees will eventually die.

Find out more about managing and protecting kahikatea fragments.

More on kahikatea

The scientific name for kahikatea is Dacrycarpus dacrydioides. These latin words refer to the tear-like sap seen on damaged trunks or branches of kahikatea and other trees in the Dacrycarpus genus.

Kahikatea:

• is one of ten tall native conifers (includes kauri, tanekaha, rimu, and matai)
• grows rapidly on fertile damp soil, but more tolerant of waterlogged, swampy soils than most native trees
• develops large buttresses (flared trunks at the base of the tree) to support them on wet ground
• has long, narrow and slightly curved leaves with pointed tips on young trees. Adult trees have leaves that are shorter and overlap like fish scales
• is a species with separate male and female trees. Male trees produce pollen in tiny cones. Females produce purple/black seeds that sit on a bright orange or red fruit-like base. These seeds are eaten by birds and other animals
• can produce several million viable seeds in a good year, if the tree is large
• seedlings grow best in well-lit situations
• can live for over 500 years and grow trunks up to 2 m across
• have young trees shaped like Christmas trees and mature trees with tall bare trunks ending with massive shaggy canopies.

Contact Waikato Regional Council’s Freephone 0800 800 401 for your free copies of the factsheet series ‘Forest Fragment Management’ and ‘Wetland Management’, or order your copies through our publications pages.