Pruning and shaping a tree is best carried
out when a tree is young, as at this stage the tree is one hundred percent living tissue as opposed to an older tree which can be ninety percent dead tissue by volume - the younger tree having more energy for its mass to resist pathogens. Potential time bombs such as branches with sharp crotch angles and embedded bark can be removed at this early stage as well. Such branches are structurally weak.

Shigo listed the five deadly sins of pruning as follows:

Wrong tree in the wrong place (i.e. may be too big for the situation).
Flush cutting.
Cutting the branch too long (harbours pathogens).
Over - pruning (tree may not have the energy to compartmentalise the wounds. The pruning in this case should be done over a number of years).
Topping trees (very dangerous, as a hollow cylinder of decay occurs with no support for the new branch that arises.

Shigo believes the best treatment for trees is health maintenance rather than trying to cure sick trees - a tree that is maintained in good health and treated such that its defence mechanisms are not interfered with, will be less susceptible to problems. For example, proper pruning can avoid the eighteen or so pathogens that can infect the tree and cause decay.

Trees have natural protection zones. With branches this zone is at the base of the branch at the collar where a chemical barrier is formed which separates good wood from damaged wood. Obviously this is the best place to prune a branch as opposed to a cut flush with the trunk, which exposes trunk tissue to pathogens. Although it may appear to heal over rapidly, the pathogens are still within and problems such as decayed wood cavities, cracks, wetwood and a host of cankers may occur.

Another important point for maintaining a tree's health is to keep grasses clear from underneath the tree (without dosing the suckers and lower branches on the tree with herbicide) as grasses are fierce competitors for nutrients and water.

Don't despair if, with all the care you can provide, certain trees do not thrive as in a natural forest situation, fewer than one percent of trees reach maturity. So perhaps the tree was not genetically fit for the situation.

Natural Target Pruning

Agriculture/Horticulture Dept, Waikato Polytechnic.

Natural Pruning Steps

Locate the branch bark ridge.
Find Target A - outside of bark ridge.
Find Target B - swelling where branch meets branch collar.
If B is hard to find - drop a line at 'AX'. Angle XAC = Angle XAB.
Stub branch to be pruned.
Make cut at line 'AB'.

DO NOT ...

Cut behind the branch bark ridge.
Leave stubs.
Cut branch collar.
Paint cuts - except for cosmetics.
Leave flat top when cutting.

To Remove Top

Cut line 'DE' at an angle approximately the same as the angle of the branch bark ridge.

Best Time To Prune... late dormant season or early spring before leaves form

Planting Landscape Trees

The performance of a landscape tree depends a great deal on how it is planted.

If the tree is mature in the landscape, it will have to grow in the soil of the planting site.
Elaborate preparation of the soil in the planting hole merely provides another artificial container for the tree, and will not ensure continued growth of the tree.
If the soil at planting site will not satisfactorily sustain a tree, extensive conditioning and modification will be needed.
Roots grow and develop in moist soil where oxygen is available. Roots grow little or not at all in dry soil or in soil that is saturated.
Trees will have shallow roots if planted on shallow soils with impervious layers or underlying shallow water table.

Digging the Hole

Plant a young tree "high", whether it is bareroot, balled, or container grown. Dig the hole no deeper than necessary - approximately 50mm less than the depth of the soil ball. Planting the tree deeper or in loose soil may lead to future crown rot problems. Loose soil in the bottom of the hold will settle, causing the tree to be planted deeper than intended.

It may be necessary to dig deeply to break up soils that have been compacted by building construction etc. When digging compacted soils, add organic matter to the disturbed soil and irrigate thoroughly. Delay planting for 2 to 4 weeks to give the soil a chance to settle.

The hole should be approximately twice as wide as the diameter of the container or root ball. When planting bareroot trees, make the hole large enough to take the roots without crowding. Backfill the hole with the soil dug from the hole. From 15 to 25% of slowly decomposing organic matter may be mixed with the backfill soil. It is advisable to add organic matter to heavy soils or extremely sandy soils. Since most nursery trees are grown in light, sandy organic soils, the organic matter will aid in the transition from the nursery soil to the landscape soil.

Competition from Turf

When trees are planted in a turfed area, keep the turf well away from the trunk of the tree during the first 2 to 4 years. The growth of young trees may be retarded by turf growing close to their trunks, even though additional water and fertiliser are applied. A 750mm diameter of bare soil about the tree also will prevent damage to young trees by lawnmowers. Mechanical damage to the trunk of young trees can have a severe dwarfing effect.

Watering

The basin for watering the newly planted tree should be so constructed that water will drain away from the trunk. Even though the soil is moist at the time of planting, thoroughly irrigate the tree to settle the soil around the root system. Remember that most of the root volume occupies a rather limited area, particularly through the first growing season. Lighter and more frequent watering may be needed until the roots become established in the parent soil. If the parent soil is poorly drained, be careful not to over water the tree.

Recommended Tree List

Staking of Trees

Staking 'A'

For plants from 8 litre + container

If plant appears to be in danger of uprooting from heavy winds, tie trunk to each stake with heavy polyethylene tape or webbing.
If plant is not staked and is in danger of uprooting, install stakes and follow above procedure.
Remove ties at the end of the first growing season.

Staking 'B'

For plants from 90 - 250 litre container or balled & burlapped.

This staking should be used when the tree will stand without support stakes, but would uproot in heavy winds.
This applies mostly to evergreen trees but may on occasion be required on deciduous trees.

Maintenance Note: Removes ties at the end of the first growing season.

Additional Notes for Maintenance

On deciduous trees remove ties at the end of the first growing season to see if they can stand alone. If the tree still needs support, lower tie if possible.
Ties on evergreen trees should remain until growth begins in spring.
Ties should be removed as soon as possible unless required for root anchorage. They should be removed at the end of the growing season.
Trees staked for support which need additional staking for protection from machinery should be staked with two additional stakes, or by using a sleeve of drain pipe (Nova-Flo) around the crown and trunk.

Tree Calendar