Trees For Rehabilitation (Landcare Reafforestation)

 TREES FOR REHABILITATION COURSE DISTANCE LEARNING

Develop a practical understanding of how trees can be used to stabilize degrading soils and improve land quality, usefulness and property value. This course has great value for all sorts of land managers and developers, from farmers to managers of public land and nature reserves. Horticulturists, agriculturists, foresters, etc can all benefit from this.

Amongst one of the most significant reasons for land degradation is the practice of clearing trees from the land, predominantly to provide grazing for cattle and sheep and areas for cropping. Agriculture is an important primary industry, which is largely responsible for feeding world populations, and as a result, economic prosperity for many nations. It has taken the very real threat of reduced yields, and such things as reduction in water quality, to provide the impetus for major land rehabilitation initiatives. Trees are seen as an integral part of a healthy environment, and it is for that reason that tree planting operations (to rehabilitate degraded land as well as prevent further damage) are being actively encouraged, by government, industry and community organisations.

Student Comment: 'I definitely learned a lot from [the course) but it was also beneficial in affirming [and raising my confidence] in what I already knew.' Katrina Merrifield, Masters Conservation Science, NZ, Trees for Rehabilitation course.

Lesson Structure

There are 10 lessons in this course:

1. Understanding Plant Health
2. Soils and Ecology
3. Basic Seed Propagation Techniques
4. Nursery Management
5. Propagation of Eucalypts and Acacias
6. Plant Care During Establishment
7. Plant Establishment Methods
8. Dealing with Erosion
9. Dealing with Chemical Degradation (Salinity, pesticides, industrial waste, fertility decline, etc).
10. Dealing with Structural Problems (Waterlogging, organic content, etc).

Aims

• Compare different approaches to land rehabilitation, to determine strengths and weaknesses of alternative options on a site to be rehabilitated.
• Determine techniques to maximise plant development in land rehabilitation situations.
• Explain the different ways of producing seedling trees for land rehabilitation purposes.
• Determine appropriate plant establishment programs.
• Develop procedures to care for plants, during establishment in an hostile environment.
• Manage the rehabilitation of degraded soil.
• Explain the effect of plants on improving a degraded site, both physically and chemically.

What You Will Do

• Determine ten different examples of land degradation on sites visited by you.
• Explain different reasons for land requiring rehabilitation, including:
  • Salination
  • Erosion
  • Mining
  • Grazing
  • Vegetation harvesting
  • Pests
  • Reduction of biodiversity
  • Soil contamination
  • Urbanisation.
• Compare the effectiveness of different policy approaches to land rehabilitation by different agencies and organisation, including:
  • Different levels of government
  • Mining companies
  • Developers
  • Conservation groups (i.e. tree planting bodies, landcare groups).
• Develop a risk analysis for a specified site to be rehabilitated, by determining a variety of plant health problems which may impact on the success of plant establishment.
• Analyse the failure of plants to grow successfully on a visited land rehabilitation site.
• Develop a procedure to enhance the success rate of land rehabilitation plantings on a degraded site you visit.
• Describe the use of mulches, to maximise plant condition in a specified land rehabilitation tree planting project.
• Explain different processes of establishing seedlings on land rehabilitation sites, including:
  • tubestock nursery production
  • direct seeding
  • pre-germinated bare rooted seedlings.
• Determine factors which affect the viability of establishing five different species of plant seedlings, from five different plant families; on a specific degraded site.
• Compare the benefits of acquiring plants for a project by buying tubestock, with propagating and growing on, or close to, the planting site, with reference to:
  • costs
  • plant quality
  • local suitability
  • management.
• Prepare production schedules for a plant species, using different propagation techniques, summarising all important tasks from collection of seed to planting out of the tubestock.
• Calculate the cost of production for a tubestock plant, according to the production schedule developed by you.
• Estimate the differences in per plant establishment costs, for tubestock, compared with direct seeding methods, for planting on a degraded site.
• Describe three different methods of planting trees for rehabilitation purposes.
• Describe different plant establishment techniques, including:
  • wind protection
  • frost protection
  • pest control water management
  • weed management.
• Describe an appropriate method for preparing soil for planting, at a proposed land rehabilitation site in your locality.
• Evaluate plant establishment techniques used by two different land rehabilitation programs inspected by you at least twelve months after planting was carried out.
• Determine the needs of plants after planting, on two different proposed land rehabilitation sites.
• Describe different, efficient ways, of catering to the needs of large numbers of plants after planting.
• Collect pressed specimens or photographs of twenty trees for a herbarium of suitable trees for rehabilitation, and including information on the culture and care of each tree.
• Describe different types of soil degradation, detected in your locality.
• Determine the risk factors involved in soil degradation, relevant to your locality.
• Compare two different alternative methods of treating each of three different soil degradation problems identified and inspected by you.
• Develop an assessment form to use for evaluating the sensitivity of a site to land degradation.
• Evaluate a site showing signs of degradation, selected by you, using the assessment form you developed.
• Plan a rehabilitation program for the degraded site you evaluated, including
  • a two year schedule of work to be completed;
  • list of quantity and type of materials required;
  • approximate cost estimates.
• Explain the effect different plant species may have resisting soil degradation.
• Explain how different plants can have different impacts upon the chemistry of their environment, including both air and soil.
• Evaluate the significance of a group of plants, to the nature of the microclimate in which you find them growing.
• Compare the appropriateness of twenty different plant species for different degraded sites.
• Determine plant varieties, suited to each of six different degradation situations.

Tips for Growing Trees

Fertilizer
You can get concentrated, fast acting fertilizers (which will feed large amounts of nutrients to the plant quickly), or slower acting, long term fertilizers ... there are many possibilities in between these two extremes.  Avoid direct contact between the roots of a young plant and the stronger fertilizers.  Usually a slower acting fertilizer is more appropriate with planting, particularly in sandy soils where nutrients can be leached out very quickly. Slow Release Fertiliser (eg. pelleted fertilisers) is ideal for planting most native trees. Be sure to check the phosphorus content of any fertilizers you intend to use, and avoid using large amounts of fertilizers containing more than a few % phosphorus. Commonly used fertilizers that have high phosphorus levels include super phosphate, hoof & horn, and blood & bone. The toxic effects of high phosphorus levels can be offset if balanced with high levels of nitrogen. Generally phosphorus toxicity is more of a problem in container grown plants than in the soil, where phosphorus is often immobile ("fixed") in the soil. The addition of fertilizers containing calcium (e.g. gypsum, lime) can make soil phosphorus more readily available. This can sometimes create toxicity problems.

Time of Planting
Planting is best timed to allow plants to settle in and establish before facing the harshest time of the year. The harshest time of year will vary from place to place, and may also vary according to the plant species being planted.

In temperate climates, planting may be done at any time of the year providing the plant will receive adequate water. In well maintained gardens, planting may be done when growing conditions are optimal ie: in the southern states planting is best done in autumn or spring when rainfall is high, and there is adequate warmth in the soil to stimulate root growth.

In tropical or sub-tropical climates planting may be better carried out after the hottest part of the year, but while the ground is still moist.

In areas with severe frosts planting may be best carried out in spring after the threat of frost has passed.
This will give the plant time to establish before the following winter.

Always avoid planting on hot or windy days   plants are more likely to dry out in these conditions.
Always avoid planting just prior to severe storms which may damage young plants.

Staking
Staking is not always necessary. It can in some cases do more harm than good. When movement of a plant in the wind is stopped completely, it may not develop sufficient strength in the trunk (known as "reaction wood") to withstand the wind when the stake is finally removed.
Plants SHOULD be staked if they are likely to fall over (ie. because they are exposed to severe winds), or if they are likely to suffer from vandalism or unintentional damage. A tree guard may alternatively be used (surrounding the plant with a tube or wall), to protect it from wind, vandalism, or foraging animals.

When you do tie a plant to a stake, the tie should be loose allowing the plant to move about in the wind.  If movement is restricted, the tree may never develop proper strength in it's join between the roots and trunk. Be sure to check as the plant grows that the tie is not restricting the growth of the plant.

Stakes can also be used simply as a marker (without ties) for small plants that may overgrown by grass, before they have had a chance to get established and put on a spurt of growth. This makes them easy to locate when you are mowing, trimming, etc.

Mulching
Mulching has several advantages as follows:

• Helps control weeds.
• Conserves soil moisture (helps prevent drying out).
• Improves soil structure.
• Adds nutrients to the soil.
• Reduces fluctuation in soil temperature.
• Can promote earth worms.
• Can reduce soil erosion.

Almost anything organic can be used as a mulch.  Here are just a few examples: wood shavings, sawdust, tan bark, pine bark, leaf mould, paper, old rags, compost, straw, prunings, weeds, lawn clippings, leather, cardboard, etc.  There are even some inorganic materials which are useful as mulches, including gravel, scoria, blue metal, coarse sand, and river pebbles.

Wind can be a problem, blowing away some fine mulches when they are first delivered, or laid down (eg. wood shavings). Once thoroughly wet, and settled however, even these mulches tend to stay where they are.