Kahikatea forest fragment planting guide
Kahikatea grows well in the open, so this is one of the quickest types of native forest to establish from scratch. After 25 years, kahikatea trees can reach 10 metres tall with trunks nearly 20 centimetres across. After 50 years, they should have formed a 20 metre tall forest stand.
Follow these steps if you wish to create a kahikatea forest for the future.
Existing trees or small groves of kahikatea in the middle of a paddock tell you it’s the right site for kahikatea. They can also provide an ideal nucleus for a new forest by planting more kahikatea trees around them:
- The worst grazing areas - the low-lying, boggy paddocks on your property - are ideal for a kahikatea forest.
- Mixed forests can be planted on drier land.
- Ideally, a new forest should be next to an existing wetland or near other patches of forest.
- If you can, join up several stands of kahikatea trees into a single block.
You can also see our map of existing kahikatea stands and of the kahikatea forest types that once would have been in your area.
The species you plant will depend on your site’s drainage and exposure:
- A boggy site is ideal for a ‘pure’ kahikatea forest.
- A drier site can support a mixture of native trees, such as matai and totara with the kahikatea
In pasture sites, rushes, Yorkshire fog and creeping buttercup will often indicate a wet or damp area. You can also look at the soil type. Check your site’s drainage by digging a soil pit to one spade depth:
- If the subsoil is white with bluish or reddish colours on the sides, your soil is seasonally wet and therefore often boggy.
- If not, it is probably has moderate to high drainage.
In very wet areas, plant trees and shrubs (even those tolerant of waterlogging) on a small mound of soil, about 20 cm high, to allow the plant to get used to its new conditions.
- Use our list of species for planting in kahikatea fragments to select appropriate plants for your site based on drainage and whether you will be planting in the open or among existing trees.
- Look at existing kahikatea stands nearby to see what is growing there.
- Look at our map to see what kahikatea forest types are, or once grew, in your area.
- On exposed sites, plant a ‘nurse crop’1 of fast-growing, short-lived shrubs like manuka or karamu.
- On more sheltered sites, light-tolerant trees like kahikatea, pukatea, kowhai and titoki can be planted in the open.
- Shade-tolerant species like tawa and pate benefit from some shelter and should be planted five years or more after the first trees are planted.
Once you know what species you want, you will need to obtain your plants.
- Talk to your nursery to ensure your plants are locally sourced and grown from seed, not cuttings.
- You can also grow your own plants. Collect seed from nearby natural areas, but ask permission from the landowner, and don’t take any plant material from reserves unless you have a permit. Avoid collecting from areas near gardens where non-local plants may have cross-pollinated with local plants.
- You can grow plants from cuttings, but keep that to a minimum, as they will be clones. Take cuttings from different individual plants to increase genetic diversity and ensure you have male and female trees.
If planting into retired pasture, first clear grass or weeds by ‘screefing’ (chipping off the surface vegetation with a spade to expose the soil). Or you can spot spray 1 m2 patches of grass at planting sites. Use a glyphosate herbicide which will not leave chemical residue in the soil.
- Planting should be done in late autumn, winter or early spring to ensure the roots become established before the dry season.
- If the site has standing water in winter and stays damp or boggy over summer, plant in late spring (October-November) to allow the plants to adjust to the wet conditions.
- Plant in clusters with shrubs and small trees planted about 2 m apart (don’t plant in straight lines, as these don’t look natural).
- Larger trees like kahikatea and totara should be planted further apart (5 m or so).
- Plant closer together if you can afford the extra plants - you will have a more natural look and probably fewer weed problems.
Seedlings often need ‘releasing’ over the first two to three years to avoid competition from surrounding grass and other pasture plants. Use a slasher or herbicide to get rid of the unwanted vegetation (protect seedlings from spray damage with cones or upturned buckets). Releasing may need to occur up to three times a year over this period. Old woollen carpet squares placed around the plant can help to keep weeds down.
- Maintain fences to exclude stock. In just minutes, trespassing stock can destroy years worth of vegetation recovery. Pay particular attention after storms, which may blow trees down and damage the fence.
- Weed invasion will be an ongoing problem, unless seed sources in nearby gardens can be removed.
- Animal pests will also require regular control. Hares are particularly tough on newly planted saplings.
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.
- Nurse plants provide a quick cover in which sensitive species can grow.