TREAT Info-Notes | Replanting the Rainforest No. 3

Planting Out

Background

You have done your planning ahead (see Info-Note No. 1). If you chose the Framework Species Method or the Maximum Diversity Method to replant the rainforest, you will be planting out small trees. It is now time to plant the new forest, and you will need to consider a number of points, including:

WHEN IS THE BEST TIME TO PLANT OUT?

Two matters must be considered when deciding when to plant out the young trees:

  1. the availability of water for the establishing young tree, and
  2. the size of the small tree.

Availability of water

During the preparation of your site (see Info-Note No. 2), you will have removed any unwanted plants and may have left the soil more exposed than usual. To decrease the likelihood of loss of soil from the site due to erosion, these operations were completed when there was the lowest possibility of heavy rainfalls, ie during the winter/ spring 'dry' in a tropical climate. However, the 'dry' is not the most opportune time to plant-out small trees.

However, if your site is prone to frost, you will need to plant out in early spring to give the trees time to develop a woody stem that can resist frost damage or will develop suckers from the base following frost damage. Because rainfall is unreliable during spring in tropical climates, you will need to provide a supply of water on a regular basis should you need to complete a spring planting.

Young trees establish more quickly when they are planted out when rains are frequent, ie during the summer 'wet' in a tropical climate. Plan your planting to begin after the wet season has commenced.

However, if your site is a flood prone area, or becomes very boggy after frequent rains, plan your planting out towards the end of the wet season.

Size of plant

Make sure your small trees are the correct size before you plan your planting out. Rainforest species establish quicker when they are 50 cm to 60 cm high at transplanting. Sclerophyll species such as Eucalyptus and Acacia species should be about 20 cm to 30 cm high at planting out. Pioneer species (see box below) should be around 30 cm.

Staking transplanted seedlings should be avoided at all times because it leads to weak stems. If the young plants are too tall to stand upright without support after transplanting, trim the stem, starting at the top and working down until it stands upright by itself.

Some common pioneer species used in tropical climates

Scientific Name Common Name
Aleurites rockinghamensisRockingham Candlenut
Alphitonia incarna Philippine Sarsaparilla
Alphitonia petrieiSarsaparilla
Macaranga tanariusBlush Macaranga
Mallotus mollissimusWoolly Mallotus
Mallotus paniculatusTurn in the Wind
Mallotus philippensisRed Kamala
Omalanthus novo-guineensisBleeding Heart
Polyscias elegansCelerywood
Polyscias murrayiWhite Basswood

HOW TO TRANSPLANT

Planting out is one of the most satisfying parts of the job of rehabilitation, but must be done with care. Remember you have invested at least 9 months of your time and some of your money in getting to this stage - planning your approach; studying your site; contacting landholders; drawing site plans; raising seedling stock; clearing the site; and preparing the soil for replanting. All that time and effort is wasted if you do not take the utmost care to make sure that the young trees become successfully established.

tree planting instructions

The accompanying diagram shows the stages to be followed in transplanting a young tree. The first step in planting out is to "harden-off' the young trees in the nursery by placing them in full sun for more than a month prior to planting into the field.

Dig the hole for the young tree. If a large number of trees are to be planted, a motorised hole auger can save a lot of time and effort, especially if the soil is relatively loose and free of old tree roots and rocks. Plant them in rows for ease of later maintenance if you wish or plant them randomly about 1.5 m to 2.0 m apart. Make sure that the hole is somewhat wider and deeper than the root ball of the tree to be transplanted by placing the tree still within its container into the hole (see diagram). It is important to make sure that the new roots have enough room to grow into during the next few months of the establishment phase.

Fertilise the planting hole before planting the tree. Add a small handful of a complete fertiliser (about 50 grams) such as blood and bone or similar organically based fertiliser to the hole. Mix the fertiliser thoroughly with some of the soil in the bottom of the hole and cover the soil-fertiliser mixture with a small amount of soil. Alternatively, you could mix half the fertiliser with the soil in the bottom of the hole, and apply the remainder of the fertiliser, again mixed with soil, to the top of the plant after planting out has been completed.

Remove the plant from its container. Disturb the root ball as little as possible. If the root mass is tightly bound or 'root bound', gently tease the outside and bottom of the root ball with your fingers to loosen some of the roots.

Place the plant carefully in the hole and back-fill the hole with soil. Form a saucer around the stem to trap water, using the soil removed when the hole was dug.

Immediately after planting, apply at least 10 litres of water to expel air pockets and settle the soil against the roots of the young tree.

HOW TO PLANT OUT

  1. Check that the hole is deeper and wider than the root ball of the tree.
  2. Add fertiliser and mix with soil in bottom of hole; cover with some soil.
  3. Remove the plant from the pot or bag; cut the bag along one side.
  4. Place the plant in the hole and carefully back-fill the hole with soil.
  5. Form a saucer to trap water around the stem with the remainder of the soil.
  6. Water in well or plant when raining.

MAINTENANCE AFTER PLANTING OUT

Mulching and weed control

Weeds, especially tropical grasses, can choke out the young trees. Invading weeds must be sprayed or grubbed-out or controlled by mulches. An organic mulch such as straw can be applied to the whole area, or to an area within 1 m of the base of the tree and the remaining area sprayed to kill germinating weeds. Be very careful not to spray the young trees.

Mowing or brushcutting the weeds is not recommended because the roots continue to grow and steal water and nutrients from the establishing young tree. There is also the risk of damage to the young tree when mowing or brushcutting.

Regular weed control will be unnecessary when the canopy of the trees closes and light levels are lowered. With good weed control, this will occur in about 12 months in tropical lowland areas and within about 18 months in tropical upland locations.

After canopy closure, the edges of the planting will provide the major problem areas. If possible, maintain a 3 m buffer strip by mowing, slashing or spraying. This strip acts as both a firebreak and a buffer against invading weeds and grasses.

When the planting is nearer maturing, the edge can be filled in with vines (eg October Surprise (Faradaya splendida), Kangaroo Vine (Cissus antartica), Milla Vine (Elaeagnus triflora), or Wait-a-whiles (Calamus spp.) or bushy species from the Lillipilli (Syzygium spp.) and Satinash (Acmena spp.) groups.

Fertilising the trees

Applying fertilisers every 4 weeks during the main growth season is an important part of after care. Firstly, remove the surface mulch. Then apply a good handful (about 500 grams of an organic fertiliser or 100 grams of a complete inorganic fertiliser) of fertiliser to each tree, sprinkling it on the top of the soil 20-30 cm from the stem. Cover the fertiliser by replacing the surface mulch. By the end of the second year, fertilising can stop because the trees will be well grown and leaf litter will be returning nutrients to the soil.


More Info-Notes

  1. Planning with a Purpose
  2. Preparing the Groundwork
  3. Planting Out (this page)
  4. Maintenance and Monitoring
  5. Planting in a Riparian Location

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