TREAT Info-Notes | Replanting the Rainforest No. 4

Maintenance & Monitoring

Background

It is now almost 12 months since you started on the project and the young trees have finally been planted out. But the job is not over - you now need a program of maintenance to make sure the young trees become established and grow quickly. You should consider:

As you watch the planting grow towards maturity, you can gain much useful information that will help you in future replanting projects. By monitoring the progress of the replanted area and evaluating your methods, you can improve your chances of success.

MAINTENANCE OF YOUNG TREES

Control weeds

Fast-growing perennial tropical grasses and herbaceous annuals such as thistles (Sonchus app.) and blue tops (Ageratum spp.), can choke out the slower-growing young trees. Regular weed control is needed until the trees have grown large enough to close their canopies and shade out the competing weed species.

Mowing or slashing are not the most successful methods of weed control. Because they do not kill the weeds, their roots continue to compete vigorously with the root systems of the young trees for water and nutrients. The most successful method of weed control is one that kills the weeds by hand - pulling; grubbing out or spraying with weedicide.

Alternatively, weeds can be controlled by mulches that prevent their seeds from germinating. An organic mulch such as straw (make sure it is free of weed seeds), shredded paper, peanut shells, or similar agricultural waste products can be applied to the whole area.

If the replanted area is large, consider mulching an area of 1m around the trees. The remaining area can then be sprayed regularly to kill any germinating weeds using a systemic weedicide such as Glyphosate (refer to product label for application rates). Be very careful not to spray the young trees.

With good weed control the young trees will grow rapidly and the canopy will close in about 12-18 months. After canopy closure, the main problem areas for weed control will be the edges of the planting. When the major tree species are 8-10.m high, the edges can be filled in with vines such as October Surprise (Faradaya splendida). Kangaroo Vine (Cissus antartica), Milla Vine (Elaeagnus triflora), or Wait-a-whiles (Calamus spp.), or bushy species from the Liliipiili (Syzygiurn spp.) and Satinash (Acmena spp.) groups.

Water the trees

Because planting out took place during the 'wet' season,- there is usually enough rainfall to provide sufficient water for the young trees. However, until the trees grow a root system extending out about 50 cm, a hot dry period of 2-3 weeks can kill them. Therefore, in the 3-4 months after planting out, be prepared to hand water if there is insufficient rainfall to keep the soil moist. Mulches will help to conserve water, as well as controlling weed species that steal, water from the young trees.

Fertilise the seedlings

Fertiliser applied at the time of planting will be sufficient for about 1-2 mouths. Additional fertiliser will be needed every 4 weeks during the main growth season for the first 2 years after planting out. Firstly remove any surface mulch. Then apply about 500 grams of an organic fertiliser or 100 grams of a complete inorganic fertiliser to each tree, sprinkling it on the top of the soil 20-30cm from the stem. Replace the surface mulch or lightly rake the fertiliser into the top of the soil (make sure not to disturb the roots of the young tree). 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.

Replant dead seedlings

If young trees die during the first year replace these seedlings as soon as possible. However if the surviving trees are about 1 m high, replacing the dead tree is not recommended because the other trees will easily out grow the new seedling and shade it out as soon as the canopy closes.

When replacing a young tree that has died, do not plant the new seedling in the same planting hole, If the young tree died from a root disease, the disease organism is possibly present in the old planting hole and may quickly kill the new seedling. A new planting hole should be prepared about 30-50 cm to one side of the old hole.

MONITORING AND EVALUATION

When you commenced your program of replanting the rainforest, you had a set of objectives you wanted to achieve. Through evaluation of our current efforts we improve our knowledge about what worked, what did not work, and what we can do to achieve greater success in future replanting efforts. Monitoring is the process of continuous evaluation, where we observe and measure what is happening before, during and after planting out.

The amount of detail collected during monitoring will depend on what you want to achieve during the evaluation process. For example, Forest Ecologists may want to make very precise recommendations on the best method of revegetation to use in a new environment. They would set out to compare the success of the 3 methods of revegetation, the framework species method, the maximum diversity method, and the natural regeneration method (See Info Note 1).

Very detailed measurements would be needed over an extended period of time (time frames of decades are common in forest ecology). Such a data set were collected by TREAT consultants in the Pelican Point Revegetation Project where the same set of measurements were collected regularly over a 6 year period. These included:

An interested environmentalist also needs to monitor an devaluate what occurred in the replanted area if they are to improve their chances of success in future replanting projects. The minimum information needed to evaluate the success of a project includes:


More Info-Notes

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

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