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  Environment » Natural Resources » Biodiversity » Forest fragments » Managing forest fragments » Planting guide

Planting guide

Weeds, animal pests and grazing livestock damage many of the Waikato region’s forest fragments. Removing these threats and replanting with native plants helps to restore these areas of vegetation. Native plantings can also join small fragments together. This provides native plants and animals with more food supplies and a larger area of forest to live in.

Photo showing people planting native tree and shrubs, which can help restore unhealthy fragments

On this page: Buffers and linkages, Existing fragments, Prepare a planting plan, When to plant, Find your plants, Planting and maintenance

Successful planting in Waikato forest fragments needs a sound planting plan. You need to know what to plant and where to plant if you want to avoid wasting time, effort and money.

Think about what you want to achieve, and whether you need to plant in the first place. It’s probably better to focus on planting the edge of the fragment and under any large canopy gaps, than in the undergrowth beneath a dense cover of trees.

For existing forest fragments, you will only need to plant inside the fragment if:

  • your fragment has been heavily grazed and has very little undergrowth
  • there is a high chance of weeds coming in
  • the tree canopy is broken up, leaving many large ‘gaps’ that can become weedy
  • there are no nearby natural areas to naturally re-seed your fragment
  • there are few saplings of future canopy trees.

Buffers and linkages

Around the edge of fragments and between fragments are the best areas to focus on. If you are fencing your fragment, leave 3-5 m between the fence and the fragment to plant a buffer.

Fast growing plants such as manuka or kanuka can be used as ‘nurse plants’ to provide shade for seedlings underneath. Plants like flax will attract native birds that will hopefully bring native seeds to add to your planting efforts. Perching posts may also attract birds. However, birds may also bring in weed seeds like privet and blackberry; so its important to check for and control weeds.

Existing fragments

If your site is near other natural areas you will probably find regrowth (natural regeneration) happening if you keep stock out and keep weeds under control. Native plants may germinate from the seeds in the soil or be brought in by birds or wind. Consider waiting for a year after fencing to see if the native plants are coming back, but keep weeds under control.

Tree species like rimu or puriri will grow much faster when planted in ‘light wells’. These are areas where the forest floor has higher light levels. One example is where a large tree has come down leaving a gap in the forest.

Shrubs and more shade-tolerant species like kohekohe, kawakawa, large-leaved coprosmas, and pate can be planted in darker areas that aren’t showing natural regrowth. Generally the larger the leaf, the more likely the plant is to grow well in shade. Avoid planting too close to the roots of existing trees.

Prepare a planting plan

Before you lift a spade:

  • Make a list of the species you will need using the planting zones to select plants suitable for your site and location.
  • Determine the size of the area, and the number of plants to be planted each year. Base this on the number of plants you can comfortably water and weed around.
  • For smaller plants (planted 1.5-2 m apart) you will need about 2500 plants per hectare (100 m x 100 m square, about 2.5 acres).
  • For larger plants (planted about 4-6 m apart) you will need 300-600 plants per hectare.
  • However, you can plant in groups to break the planting up over many years, and let nature help fill in the gaps with self-seeded plants.
  • Draw a rough plan of your site, showing where aspects such as damp, dry, steep, flat, sheltered, windy, sunny and shady areas are. Decide where you want walkways and other features. Note which species you should plant where, based on factors such as wind, drainage, and light (see the planting guide). Don’t waste time and money by putting plants where they won’t survive. Let nature ‘tell’ you what type of site each plant prefers by looking at nearby native forests.

Find out more about the types of native vegetation in the region’s forest fragments.

Find out what to plant in kahikatea fragments and in wetlands.

When to plant

Plant hardy frost tolerant species in autumn, and frost sensitive species in spring. Plants requiring shelter or shade can be planted three to five years later, once cover has developed. Planting under the tree canopy can be safely carried out any time from autumn to spring. This is because the forest floor under a healthy canopy will generally be frost-free.

Find your plants

  • Buy plants from nurseries that grow their plants from seeds collected from within your district (‘eco-sourcing’) to ensure they’re suited to your area’s climate and soils.
  • You may be able to grow some of your plants from seeds or cuttings taken from other fragments near yours. Always seek permission before taking any plant material. Cuttings will be clones (they will have identical genes), so don’t use too many of them.
  • For a higher chance of survival use larger potted plants. These are also less likely to be uprooted by native birds such as pukeko or bitten off by hares.
  • Some species have separate male and female plants. If you are planting a small area make sure you have at least four to five plants (not cuttings) to ensure fruit production.

See our information and contacts page for a list of some of the region’s native plant nurseries.

Planting and maintenance

Remember that most native plants cannot survive if they are grazed by stock. Fence prior to planting to protect your investment. Remove weeds from within and next to forest fragments before planting. Make sure you know which plants are weeds, and which are native plants that typically occur in your forest type.

  1. Set plants out in sites with suitable conditions for them to grow in. Plant shrubs and small trees 1.5-2 m apart, as competition may kill some plants. Large, spreading canopy trees like puriri or tawa may eventually reach 10 m or so across. Place these (often more expensive) plants further apart, but put smaller plants between them to avoid weed invasion.
  2. Plant in groups. The plants will soon shelter each other and begin to shade out surrounding weeds, making your job easier. More plants can be added to the edge of each group as time and resources permit.
  3. If the planting area is currently in pasture or weeds, clear a 1 m circle around each plant with a spade or a herbicide to ensure the new plants will get enough light and nutrients.
  4. Dig a hole twice the size of the plant container, leaving some soft soil at the bottom. Set the plant in the hole. Gradually fill in the soil and pack it down to remove air gaps. If a post hole borer is used, scrape around the sides of the hole with a spade to allow the roots to get into the earth more easily.
  5. Form a hollow around the base of the plant to trap rainfall on dry sites. Give the plants and surrounding soil plenty of water. Water young plants over dry spells.
  6. Staking the plants at this stage will make them easier to locate later. Tall, thin bamboo stakes highlighted with spray paint are ideal.
  7. In sandy or clay soils, organic matter such as well-rotted manure or compost can be added to improve soil structure. Dig it into the soil at the bottom of the hole or use around the plant as a mulch.
  8. Smothering by tall grass is the most common cause of planting failure. Control weeds for the first few years, and consider placing weed mats around plantings. Use materials such as carpet or underlay that are made of natural materials which break down into the soil over time. Once native plants have grown tall enough they will begin to shade out grasses and weeds, and no longer require a lot of weed control.
  9. Use mulch, such as compost, newspaper, old carpet underlay, rotted hay, or wood chips that haven’t been treated with chemicals. Mulch can help keep the soil moist, slow down weed growth and add nutrients. Don’t let the mulch touch the stem or it may rot the plant.
  10. Pests such as rabbits and possums will need to be controlled, particularly before planting and during the seedling stage.

Find out more about controlling pest and weeds in forest fragments, and protecting your fragment for future generations.

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