Given all the things that can go wrong as a tree grows from a seed to a 30-metre giant, it’s incredible so many survive.
However, survival and healthy growth are not necessarily the same things and there are quite a few actions you can take to stack the odds in the trees' favour.
Before you plant
When to plant?
The best time to plant is from May through August, once the ground is moist. If irrigation is available, you can plant throughout the year.
Seedlings will be available from your nursery from about May onwards.
Trees won’t survive in dry soil. In dry winters, planting should not take place until enough rain has fallen to make the ground easy to dig.
Match the right tree to the right site
Look at your site and list the limitations it may have. In areas that are frost-prone, have poor soil, are swampy, dry or have very sandy soil, a tree may survive but be stressed and vulnerable to disease.
Choose varieties resistant to any problems your site may have, to save you time and money later.
Order a realistic number of trees
How many trees can I expect to plant in a day and look after for the next 18 months? Remember planting is the easy bit – ensuring they survive takes time and effort.
A reasonably fit person planting into spot sprayed pasture using a sharp planting spade on country that is not too steep should be able to plant 400-450 pines per day. For other species, or if your planting situation is more difficult, reduce this number.
It’s better to plant all your trees and have some time left over, than to order too many.
Treat your seedlings well
- Check seedling quality before leaving the nursery – ensure that there are plenty of roots and they are moist.
- Transport them carefully and make sure roots aren’t crushed.
- Trim the roots if they are longer than 10cm, so they don’t become misshapen.
- For bare-rooted seedlings, don’t order more than you can plant in two days.
- Keep boxes of seedlings out of the sun to protect the plant roots and prevent plants from overheating.
- Cover seedlings with a damp sack and put them in the shade and out of the wind.
- Leave seedlings in the pot/box until immediately before planting.
Bare rooted or not bare rooted?
Bare rooted trees are usually cheaper than containerised stock, but have a short window for planting – generally within 48 hours of lifting from the nursery, extended to a week if refrigerated. Plants that aren’t bare-rooted can be kept until they grow out of their containers, so planting is more flexible.
Prepare the area to be planted
The most important things you can do to give your trees the best chance of survival are:
- fencing out stock – this is essential
- reducing competition from other plants by:
- grazing the area very hard before spraying (if spraying) and immediately before planting to give the seedlings a head-start on competing grasses
- spot spraying where each tree is to be planted, about six weeks before planting. If using a residual herbicide, spray 10-12 weeks beforehand
- having the plants close enough to suppress weeds quickly
- controlling pest plants and animals – the regional council’s biosecurity team can help with advice
- ripping the ground to be planted (if severely compacted).
The best way to learn how to plant trees properly is to see it done and then have a go. The Northland branch of the Farm Forestry Association has regular field days to give people this opportunity.
Digging your holes
- a good planting spade is essential and there are specialised ones available
- bury the spade blade to its 25 cm depth on each cut
- on the last cut make sure to break through any soil pan below
- make sure the soil around your hole is well cultivated, to about 300 mm wide and 250 mm deep.
Planting your trees
- trim any deformed roots and those longer than 10 cm
- plant your tree straight (within 20 degrees of vertical)
- make sure the roots point downwards, are straight and have no air pockets around them
- check your depth - bare rooted seedlings can be buried with up to one-third of the greenery in the ground, while container seedlings should be planted deep enough so that the soil plug is completely buried
- when compacting the soil around the tree use the heel of your boot, making sure not to get closer than 50 mm to the stem
- mulch around the plants to keep weeds down.
- exclude all heavy stock for as long as it takes to get the trees established. This may be as little as two years (poplar poles) or permanently (for native revegetation). Closely monitor any sheep grazing to prevent damage to the bark
- keep up the pest control. Don’t let rabbits, possums or goats kill or damage your young trees
- clear any competing weeds/grass from around your plants until the trees are well above surrounding weeds. This can be done by using herbicide sprays or manually clearing weeds away from trees. Scrub cutters or other mechanical tools are not recommended because these can damage the bark of young trees
- apply the right fertiliser when the trees are young. Knowing your soil’s natural fertility will help you get the right one for the job – soil tests are recommended
- if your trees look unhealthy and you’re not sure why, get advice from an expert.
If you are considering investing in tree planting, it’s worth getting advice – here are some places that can help.
Northland Regional Council’s land management team – advice on land management, erosion control, flood control and drainage, land use capability, activities that might need consent (like logging, land clearance, land/water disturbance), biodiversity values and funding for protection, shelter and shade and weed and pest control.
Contact a land management advisor
Farm Forestry Association – advice for those with small forestry blocks.
Tane’s Tree Trust, including the Northland Totara Working Group – promoting the use of native trees for its timber values.
New Zealand Landcare Trust – help for community groups.
QEII National Trust – help with protecting and covenanting native bush and wetlands.
Your district council – for information about consents for changing land use.
Get contact information for your district council