Natives for Timber or Amenity
By Indigenous Forest Section, July 2008.
Nothing can be more rewarding for a forester than creating and nurturing a native plantation from 10 years on their size, growth rate, form and rapid maturation looks and feels more like our natural bush!!! But behind every success story there is a lot of work, and many others that have failed!! This article is written on the assumption you are interested in planting a 0.4 hectare block or more. Naturally established natives are generally not included in this summary. Nursery grown stock is not covered.
Natives take a long time to establish. It may be 3-4 years after planting before you can be assured they are reasonably established. That translates into high costs allow $9-$10 per tree or shrub! A budget will be imperative to see you have enough money!!
But before you plant, check your local District Plan carefully! Don't just take your council employees information as gospel either. A recent survey found many council employees gave out incorrect information on native plantings. Get a copy of the District Plan and research it carefully. Or talk to someone who has. Most District Plans have scattered, unrelated and conflicting references to forestry, and natives. Check the definitions! Forestry and natives may or may not be mutually exclusive terms. Some District Plans do not allow cutting down of any natives, planted or natural, over 3 metres in height. If you need a consent, get one! After your research, get a written affirmation from the council as to what the rules are, before you plant one stick, and keep this copy for ever! Also, check with your Regional Councils, they are usually more helpful but only cover water and pest management concerns.
Outside of local council rules, generally the law; allows you to harvest native trees that have been planted unless you give up that right. Try to get the council to write down or register the details of the natives you have planted.
This varies according to whether you are in business (by IRD rules) as a farmer, a forester, or a property developer! To be a forester, 2 hectares is often considered the minimum forested area, to show you are not a hobbyist. If the district plan disallows cutting down trees at the time you put your plantation in, you will not have a forestry business!
Most plantings will hopefully be deductible check with your chartered accountant consider using a company as natives are long term, and share ownership can protect you from a deemed sale. For your protection, make sure any purchase of an existing block (including natural bush) has an agreed valuation on the trees in the sale and purchase agreement. Forestry rightsmay also be useful planning tools.
The aim is to effect rapid crown cover, self sustaining growth and to shut out weeds. Anything over 2m x 2m initial planting spacing compromises this. Plant a tree that can quickly get over grass height, but will not be socketed by wind and sulk! Unless you are coastal, or a beech grower(!), hardwoods often require an already established nurse crop...quite a management art that!
Grass is your biggest threat in the first few years. Later on, blackberry eventually establishes with any extra light and pulls down established trees - hence rapid canopy closure is the aim. The shrubby natives give your best crown closure. Gorse should be cleared before planting, and followed up with spot sprays.
Roundup and Gallant (kills grasses only) can be used from planting and onwards. Residual weedicides knock natives. The spots around trees need to be at least 1m in diameter to stop grass falling in wider on the high side if sloping ground. Four to five sprays may be needed through to year 3, depending on growth. Costs 30¢-35¢ per plant per time sprayed. Weedmats and mulches can be tried but they may stop summer rainfall being effective unless well designed and may be more labour intensive.
The jury is out on this still! Much will depend on your management. Pure species stands will require thinning. Mixed timber trees with fast growth shrubs may well require earlier releasing and then later thinning. Blocks close to existing natural bush stands will more quickly have natural bush species introducing themselves. To make sure you have sufficient timber crop trees, pruning may well be wise. Prune similar to that done for Acacia melanoxylon: i.e. three rules:
- If a branch is over 3 cm in diameter, take it off!
- If the branch is 30 degrees or less to the main stem it is a steep angled branch; take if off no matter what the size!
- Check the top 3 metres of the tree and form prune, so that you leave only one leader, now! All the rest of the branches should be retained to help maintain the rapid growth you want.
For older existing trees of poor form, give them a go, prune them now, you'll always look back later glad that you did. Take up that jacksaw or chainsaw!
Final spacing?? Check known natural stands final spacing of the age you hope to harvest at. Acacia melanoxylon growers aim for fast fat trees in 35-40 years. They want one good 6m log-tree about 200 stems per hectare final spacing. Podocarps can grow closer than that, and have better apical dominance and naturally good timber form!
Consider tending cost!!! Most natives respond to pruning. But with the long wait, will the outlay justify the cost? Should your management system reduce this? (e.g. planting into manuka/kanuka? Will you be patient for results? Will higher fire risk be a threat?) Prune for love and it won't matter!!
Totara and Kauri: Well known, fast, some research results available already, prime timber species.
Silver Beech and Black Beech: Have surprisingly fast growth rates most places in the North Island. Red beech is less reliable to establish. Correct beech soil mycorhiza should be included with your planted trees. Check what your nurseryman does (or knows!).
Kahikatea and Tanekaha: Less favoured timber species but fast growth in a wide variety of sites. Don't stake drooping tanakaha leaders. They'll right themselves.
Karamu: One of the fastest, best performing shrubby canopy covers!
Puriri, Rewarewa, Kokekohe & Mangeao: Most favoured manageable hardwoods for the North Island.
This article is based on a few peoples experiences only. The following publications and organisations and their field days are thoroughly recommended for building your own knowledge, observations and contacts:
- NZ Tree Grower articles (NZ Farm Forestry Association and their Indigenous Action Group, PO Box 10349, Wellington) Ph 04- 472-0432.
- Indigenous Forestry Sustainable Management, Ministry of Agriculture, Forestry & Fisheries.
- Tane Tree Trust; Leaflets & Field days, c/- I Barton, 40 Isabelle St, Pukekohe. Ph 09 239-2049