Agroforestry

This page has been developed to provide information on Agroforestry in Central Queensland. Major topics discussed include; what is Agroforestry, plantation establishment, problems, and markets. Also included is a Links page containing relevant sites where additional information can be obtained.

In July 1996 the Commonwealth Ministerial Council on Forestry, Fisheries and Aquaculture endorsed the plantation industry’s target of trebling the plantation estate by 2020. To achieve this goal, the Council agreed to develop a realistic and achievable national strategy. The resulting document called Plantations for Australia: The 2020 Vision focuses on accelerating plantation development in Australia. It has identified the availability of land as a major obstacle to realizing the Vision.

Here agroforestry has a major role to play as it has the ability to combine existing agricultural land uses with plantation development thus increase the land available for plantations. Agroforestry also has an role in rehabilitation of degraded lands and improving environment amenity.

Agroforestry is a relatively new and untested concept in Australian agricultural operations. This combined with the long cycles for timber production indicates it may be a challenging enterprise to undertake. Much of the uncertainty and unknowns associated with Agroforestry may be overcome by the acquisition of good information and development of effective management plans and practices. This CD-ROM is designed to provide starter information for potential Agroforestry operators and directs interested parties to websites where more detailed information is available.

What is Agro Forestry

Agroforestry is the management of trees for forest products. It can be an integral component of productive agriculture. It has application to multiple use agricultural land, or as a single land use. It may include existing native forests and forests established by landholders. It is a flexible concept, involving both small and large sized land holdings. These forests are multi functional, serving several purposes simultaneously.

Agroforestry has the potential to combine four elements of land management:

  • Agriculture
  • Land Protection
  • Forestry
  • Conservation
  • Agricultural Element

Shelter and Shade

Agroforestry provides protection for stock, crops and pasture as follows:

Increased stock performance

Agroforests protect stock from summer heat and winter cold. This can improve weight gain, milk production and fertility (Race, 1993). Unsheltered stock uses energy handling the stresses of heat and cold and have less energy available for production.

Increase crop and pasture yields

Production is lost near trees but is more than offset by the gain in production within the rest of the sheltered area (Race, 1993). This is associated with reduced influence of wind, therefore increased water retention and stability of moisture levels (see Diagram 1).

Diagram 1. Production and Shelter

Nutrient Recycling

Tree roots take up nutrients that have leached beyond the reach of pasture, returning them to the topsoil when leaves fall and decompose.

Forestry Element

Agroforestry can produce high quality valuable timber when trees are effectively selected and managed. Other tree products, such as fence posts, strainer posts, seeds, nuts and flowers can also be produced on the farm to increase economic diversity and income.

There are several forms of planned agroforestry and three of these are briefly discussed here.

Timber Belts

Timberbelt PlantingTimber belts generally consist of 10 or less rows of closely spaced trees that provide shelter (windbreaks and stock shelter) and other commercial tree products. These plants can be managed to produce high quality knot free timber. Eucalypts, pines, cypress, acacias, poplars and grevilleas may be suitable (Cremer, 1990).

Timber belts incorporate a slow growing supplementary species to provide low shelter and protect against the effects of winds. These species may also produce useful products. When the timber species is felled these supplementary species will have grown sufficiently to provide shelter by themselves. It is anticipated that the main benefit associated with this form is the protection it offers surrounding lands and stock.

Timberbelt planting

Wide Spaced

For ease of establishment and management wider spaced trees are planted in rows, often one species per paddock.

Horticultural cropping or silage production during the trees establishment years can be combined successfully in this wide spaced form of planting. Livestock can be introduced to a wide spaced agroforest when the trees have been established or when their protection can be provided. It is anticipated that agricultural production from wide spaced agroforests will decrease over time to a negligible level as the trees mature ready for harvest (Race,1993).

Wide Spaced planting

Cluster

Cluster planting is a circular design that combines timber production and shelter. It allows for economic fencing of trees during establishment years. It also allows for high density plantings of mixed species to be easily incorporated into current agricultural practices. When established it offers shade and shelter for livestock and saleable forestry products.

Land Protection Element

Salinity and Water Table Control

Salinity is mainly caused by rising water tables (McDonald, et.al.,1994). Trees help to lower water tables, acting as pumps to take up water from the soil and then evaporating it to the atmosphere (see Diagram 2.)

Diagram 2. Trees and the Water Table

Soil Erosion Control

Soil erosion or loss results from the action of wind and water on unprotected soils. The forest canopy, roots and leaf litter all have a role in controlling soil erosion.

Water Logging

By water removal, established trees can substantially reduce water logging in their immediate area, which may result in improved land uses, e.g. pasture or crop.

Conservation Element

Indigenous Species

Use of trees of local genetic origin will maintain the biological structure of the local native flora and fauna. Also indigenous trees are often better adapted to local conditions than non indigenous trees and have higher productivity.

Wildlife Habitat

Trees support many forms of wildlife and increase biodiversity. Many of these species of wildlife (birds, insects) play a major role in controlling outbreaks of crop and pasture pests.

Plantation Establishment

Growing trees for agroforestry is a long term investment requiring careful planning and good planting techniques for a successful enterprise. This section on production briefly discusses several topics including in order: planning, site selection, site preparation, planting and management.

In relation to management attention is given to fertilising, weed control, pests and diseases. Also a description of pruning and thinning for improved timber production will be included in the management discussion.

This discussion on production should be viewed as starter advise and more research on specific topics may be required. Also different production methodologies may be necessary due to the influences of site conditions, species selected and size of operation.

Planning

When planning the plantation consideration should be given to the following areas. This may require seeking expert advise.

  • Assess the potential for your resource: land, capital and time. Also consider alternative land uses in this context.
  • Local government regulations for land management, codes of practice and harvesting applicable to your area.
  • Tax and insurance matters governing your enterprise.
  • Market research – projected value of your plantation and how this may change.
  • Be aware of the associated costs of managing the enterprise – major factor in determining size of operation.

Site Selection

Most land can be planted if tree species are selected carefully (Abel, 1997). When choosing a site for a plantation several factors need consideration:

  • Conform to current, regional management and tenure policies. Check with local government authority and forestry office.
  • Be clear of permanent water ways and power lines.
  • Be bordered by adequate fire breaks.
  • Have good access for maintenance and harvesting.
  • Have appropriate slope i.e. 20degrees to allow planting and harvesting operations.
  • Be suitable for the species selected to plant.
  • Have soils at least 1 metre deep with a pH between 5.5 and 7.5 (Bailey, 1999).

Site Preperation and Planning

Before planting it is essential that the site be prepared to a high standard. Benefits such as ease of planting, increased tree survival, better weed control and improved growth rates will far out weight the time and effort involved in site preparation. The following discussion identifies the 6 steps to establishing a plantation and contains a brief overview of each step.

Step 1. Clear and Fence Site

  • Remove weeds, regrowth and rubbish from site.
  • Fence site if required.

Step 2. Mark Out Planting Rows

  • Wide enough apart to allow access to maintenance and harvesting equipment.
  • On slopes run rows along the contour.

Step 3. Ripping And Cultivation

  • Deep rip to 70 cm along each tree row when soil is dry.
  • This shatters the subsoil reducing soil compaction and improves moisture infiltration.
  • After ripping, cultivate using offset discs or harrows to produce a finer soil tilth.
  • This breaks up clods, makes planting easier and reduces air pockets in upper surface layers.

Step 4. Wait For Rain And Pre Plant Weed Control

  • Increases soil moisture and helps settle the soil.
  • Spray for a continuous 2 metre wide weed and grass free strip along every proposed treeline which is over the ripped line.

Step 5. Planting

  • After rain when soil is moist.
  • 1000 stems per hectare (4m x 2.5m) is a good stocking density for timber production as it. forces trunk extension, reduces branching and reduces weeds (Bailey, 1999).
  • Plant in blocks of between 20 to 50 trees of the same species.
  • Rainforest species may perform better if species are mixed.
  • Soak seedlings in their pots prior to planting out.
  • When planted seedlings must be in shallow depression.
  • Water in well.

Step 6. Post Planting Weed Control

  • Aim is a weed free zone of 1.5 metre radius until trees reach 4 metre height.
  • Use herbicides and/or mulch.

Management

Fertilizer

Requirements are often species specific and the nutrient requirements of the species planted need to be assessed before a fertilizer regime can be developed. This assessment should identify the appropriate fertilizer and application rates.

Usually fertilizers are applied at planting and should not be placed too close to plans as this will cause damage. Doses should be placed at least 30cm from the plant on the downhill side. Follow up application commonly occurs after 9 and 18 months.

Weed Control

It is essential to maintain effective weed control until the trees are established and have grown enough to be away from the influence of weed and grass competition. This is vital to good tree growth and the successful production of a wood crop in a reasonable period.

A weed free zone of 1 to 1.5 metres radius is required around each tree for at least the first year of growth and preferably for the second year or until most trees are over 4 metres. This can be achieved by a variety of methods including the use of herbicides, hand weeding and the heavy application of mulch.

The general area is best maintained by regular slashing. For specific weed problems physical removal or spot herbicide application may be useful.

Pests and Diseases

Insect pests and fungal diseases may develop in the plantation, so periodic inspections are recommended. If damage to the foliage exceeds 40-50%, contact appropriate personnel for advice, e.g. local forestry office. In most situations spraying is avoided and natural populations of predators and parasites are allowed to control out breaks of insects. Matching tree species to your site and maintaining plantation vigor will help reduce the incidence of attack. Find out about the likely susceptibility of a species to insect damage before planting on a large scale.

Pruning

The lower branches of agroforestry trees are pruned to :

  • Grow high quality, high value timber.
  • Reduce shade and promote pasture growth.
  • Improve access and visibility.
  • Reduce fire hazard.
  • Increase tree stability in windy areas.

Most trees can be pruned to improve timber quality and value (Keller, 1996). Log value is determined by the size and straightness of the tree trunk and the number of knots and branches. Pruning the branches reduces the size and number of knots. Large, straight, knot free logs (clearwood) command the highest prices (Keller, 1996).

There are two basic types of pruning.

  • Form pruning – the selective removal of branches to produce a single straight trunk and aids future pruning by controlling tree form.
  • Clearwood pruning – the removal of lower branches in such a way as to grow the maximum amount of knot free wood.

When to Prune

Clearwood pruningThe frequency, season and standard of pruning varies between species, growth rates and the length of clearwood to be produced. Pruning usually begins 2-3 years after planting and continues until the tree trunk is pruned to the desired height. This is often up to 6 metres. It is essential that all pruning be done on time. Premature pruning wastes time and effort, while delayed pruning results in large loses of valuable clearwood.

Clearwood pruning

Knots are branches that become incorporated into the wood of the tree trunk as it grows. Removal of branches results in knot free timber called clearwood. Clearwood is valuable for veneers, which are obtained by cutting thin layers of timber from logs. Veneers improve the finished appearance and value of lower quality timber products.

Clearwood pruning

Clearwood pruning guidelines

  • Start pruning when trees are between 4-6 metres tall.
  • Prune lowest branches first, working up the trunk.
  • Always leave 3-4 metres of crown at the top of tree.
  • Form prune above the clearwood pruned trunk to ensure a single straight stem.
  • Prune only to the desired saleable log length.
  • Prune each tree according to its height and diameter.
  • If possible undertake thinning in conjunction with pruning.
  • Remove branches close to the collar but don’t cut the collar, as this will impede healing.
  • Small branches should be removed with pruning shears or secateurs (Diagram 1).
  • Large branches will require a pruning saw and several cuts to avoid tears (Diagram 2).

Diagram 1. Pruning small branches - Diagram 2. Pruning small branches

Thinning and Tree Selection

There are two reasons why more trees are planted than are required.

  1. Allows for the selection and management of the best trees for final crop trees.
  2. Forces the plantation to grow tall and straight with less vigorous lower branching (Reid and Wilson, 1986).

Thinning is done to maximise the growth of the final crop trees and minimise the number of trees to be pruned.

When to Thin

First thinning should be done at first clearwood pruning. Early thinning is biased towards malformed and smaller trees to ensure the right planting density is maintained and to allow resource use to be concentrated on the better trees. As trees grow older they require more space to grow. The amount and timing of thinning older trees depends on growth rates and initial spacing. Crowding of the tree crowns gives a rough indication of when thinning is necessary. Once tree crowns close in and almost touch, the plot needs thinning.

Selecting Trees

Reid and Wilson, 1986 have developed two criteria for the selection of trees to be removed and those to be retained and pruned.

Trees that are to be thinned out immediately

  • Do not have straight trunks.
  • Lean more than 5 degrees.
  • Have missing, broken or dead tops.
  • Have multiple stems or very large branches.

The trees that are the best to prune are those that

  • are vigorous i.e. tall, healthy with large trunks
  • are the straightest
  • are well spaced i.e. have enough space to grow freely

This process of selection and thinning should be carried out at each pruning visit or until the final number of crop trees is reached.

Problems

The following points are problems associated with agroforestry. It is anticipated many of these problem may be overcome by good research, effective planning and collaboration with other tree growers and Government forestry officers.

  • Agroforestry is a relatively new concept in tropical and sub-tropical Australia and limited information is available about species performance and selection (Capill, 2001).
  • Long production times requiring capital and labour intensive maintenance.
  • Choosing the correct species to insure maximum returns.
  • No magic species and time consuming trails must play a major role in all agroforestry operations to determine the most suitable species to be grown.
  • Long production times and associated management cost over this time may exceed or reduce returns of the final saleable product.
  • Small farm plantations and irregular supply have been of limited value to buyers of forest products (Gill, 1999) .
  • Tree growers often lack the capital resources and technical knowledge necessary to ensure the production of high quality marketable timber (Gill, 1999).
  • Most tree growers only plant, tend and harvest once in a lifetime, therefore often lack forest management and marketing expertise.
  • Small tree growers cannot take advantage of professional forestry services as readily as owners of large plantations can (Gill, 1999).
  • At this point in time there is uncertain by many potential agroforestry operators in relation to the status of plantations and how the various.
  • Vegetation and Environmental Legislations are and will be applied in the future.
  • Agroforestry is a agricultural enterprise and subject to all the associated seasonal problems e.g. drought, fire, pests, diseases and floods.

Market

Investigations into the potential uses and markets for agroforestry products should begin before the trees are planted. This will coincide with site and species selection. Given agroforestry is a relatively new concept only limited information about marketing processes is available and most information has been adapted from conventional large scale public owned forestry (Capill, 2001).

This discussion focuses on several topics relevant to marketing timber products, including products, type of sale, point of sale, market trends and location.

Products

Saw logs, veneer logs and chipwood are high value forest products (Kellas, 1996). Selling the wood for a satisfactory price is difficult if there are few potential buyers within an economic haulage distance. This highlights the need for effective market research prior to plantation establishment to identify buyers and their location.

Saw Logs & Veneer Logs

Pruning to produce knot free clearwood may add considerable value to the wood for appearance grade products. Mills purchasing saw logs set minimum size and quality standards. These standards vary between mills and products. As a generalization for softwoods a common minimum length is 2.4 metres with a minimum small end diameter of 15cm under the bark (Kellas, 1996). For hardwood a minimum length of 3 metres and diameter of 25cm is common (Kellas, 1996).

Chipwood

Chipwood refers to timber used for paper pulp and chipboard production. It is usually a softwood species and currently in over supply in most regions due to the extensive State Government plantations e.g. radiata pine (Capill, 2001).

Although chipwood from certain fast growing eucalyptus (E. globulus, E. nitens, E. regnans) is currently in high demand (Capill, 2001) .

Smaller logs are suitable for pulpwood e.g. 10cm small end and there are less demanding standards for straightness and knotting (Borough,1992).

Others

Other possible products include poles, posts and sleepers. These often require preservation treatment.

Point Of Sale

There are three options for point of sale (Cremer, 1990).

  • Wood on stump (stumpage).
  • Logs at mill door.
  • Sawn timber.

Stumpage

The trees are sold on the property and it is the responsibility of the buyer to harvest and remove the timber. Factors affecting the price include haulage distance, harvesting difficulty, access road, log size and quality, volume of supply and bargaining power.

Logs At Mill Door

The grower performs the above task or employs contractors to perform it. The price is then negotiated for a product delivered to the processor.

Sawn Timber

The grower mills the timber on the property and sells sawn timber to wholesalers. This effectively removes processors and increases the return to the grower.

It is anticipated that sawn timber is the preferred option of smaller agroforestry operations as it value adds and increases profit. The development of portable saw mills has assisted in making this option available to agroforestry operators (Capill, 2001).

Products such as railway sleepers are sawn into their final form in the forest.

Type Of Sale

Two approaches are possible:

  • entering into advanced contracts
  • negotiating private marketing arrangement when the timber is approaching maturity.

Advance Contracts

In some areas there may be an option to sign a preplanting contract with a processor. The timber when ready is then sold to the processor at the current market prices. This guarantees a market, however the price at harvest remains uncertain. These contracts are generally limited to a few species that are of interest to large scale industry e.g. radiata pine and eucalyptus for pulp on short rotations. Plantation sizes are usually no smaller than 20 hectares which can make the venture more like conventional forestry than agroforestry. However processors are becoming more willing to enter into contracts of smaller areas (Capill, 2001).

Private Marketing

As an alternative trees can be grown and marketing take place closer to the time of harvest. For this approach it is desirable to have a knowledge of existing markets and to study trends in demand and supply of related products. However it is difficult to predict markets and prices decades into the future and an element of speculation must remain in tree growing.

Market Trends

The price of timber has approximately followed the inflation rate in recent decades (Kellas, 1996). In future, the price of timber may increase faster as a result of such factors as world economic growth, especially in Asia and reduction in sustainable supplies from native forests (Kellas, 1996). Other factors such as large expansions in plantations in a number of countries may have an opposing effect.

The prices of possible substitutes such as steel, concrete and oil will set competitive limits to the price of wood for some uses, but are unlikely to affect the price of specialty timber (Kellas,1996).

Location

Unless the tree growers are close to the market, they will have difficulty selling their wood or suffer a discount on its value as cartage costs are approximately 10cents/km/cubic metre on highways and 20cents/km on country roads (Kellas,1996). Unless the logs are high value the supplier needs to be within about 100km of the market.

The present location of mills gives and idea of cartage zones for harvesting in the next few years. It must be remembered that these mills may not exist in 30 years time. This situation combined with the increased profits associated with the sale of sawn timber indicates that on site milling may be essential for smaller agroforestry operations.

Co-Operatives

This section discusses tree growers co-operatives. Topics discussed in order include:- what is a co-operative, need for collaboration, benefits and function. Tree growers co-operatives are successful mechanisms for improving the market position of small scale forest growers. They assist growers by being able to plan and aggregate harvests and therefore attain the volume and reliability of supply that is generally required by the buyer.

What Is A Co-Operative

‘A co-operative is a business enterprise organised, owned and controlled by the persons who use its services. It enables individuals and businesses to gain the benefits of joint endeavour while maintaining their independence. (Gill, 1999)

Co-operatives are given legal standing and effect in Australia through State Government legislation. In Queensland the legislation involved is the Co-operative Act 1997 and Co-operative Regulations 1998 (Gill, 1999). To be recognised by these legislations co-operatives must be guided by seven internationally recognised principle (Gill, 1999) . These principles are:

1. Voluntary And Open Membership

  • Open to all persons able to use their services and willing to accept the responsibilities of membership

2. Democratic Member Control

  • Democratic organisations controlled by members.
  • Elected representatives are accountable to the membership.
  • Members have equal voting rights.

3. Member Economic Participation

  • Members contribute equitably to, and democratically control, the capital of their co-operatives.

4. Autonomy And Independence

  • Co-operatives are autonomous, self help organisations controlled by their members.

5. Education, Training And Information

  • Co-operatives provide education and training for their members.
  • Inform the public about the nature and benefits of co-operatives.

6. Co-Operation Among Co-Operatives

  • Co-operatives serve their members and strengthen the co-operative movement by working together through local, national, regional and international structures.

7. Concern For The Community

  • Co-operatives work for the sustainable development of their communities through policies accepted by their members.

Need For Collaboration

Many individual tree growers have tried unsuccessfully to secure markets at satisfactory returns for their forest product. The following factors identified by Gill, 1999 have contributed to the mixed success of farm forestry. The problems associated with these factors may be reduced by collaboration and co-operative formation by tree growers (Gill, 1999).

  • Small farm plantations and irregular supply have been of limited value to buyers of forest products.
  • Tree growers often lack the capital resources and technical knowledge necessary to ensure the production of high quality marketable timber.
  • Most tree growers only plant, tend and harvest once in a lifetime, therefore often lack forest management and marketing expertise.
  • Small tree growers cannot take advantage of professional forestry services as readily as owners of large plantations can.

Benefits

To Tree Grower

  • Generate economies of scale in marketing and purchases.
  • Provide opportunities for exchange of information.
  • Inform members of opportunities for targeting niche and commodity markets.
  • Investigation of new markets and value adding opportunities.

To Industry

  • Overcome the problems of organising supply from a multitude of small growers within a region.
  • Increase and diversify resources.
  • Influence the planting of timber species and management practices that meets their future needs.
  • Reduce the need for industry capital to be invested.

Function

Gill, 1999 identifies a diverse range of services that co-operatives can providers to tree growers . These include:

  • Market Development
    A function of a tree growers co-operative should be to research the long term needs, wants and preferences in existing and new markets.
  • Supply Information
    Information supply is a critical function of a tree growers co-operative. It can sponsor field days and seminars
  • Forest Management Plans
    Prepare forest management plans including forest improvements, management and harvesting activities.
  • Resource Inventory
    Development of an inventory and valuation of all the timber resources of the co-operative.
  • Timber Marketing
    Secure sales and negotiate contracts on behalf of its members. The co-operative may purchase from tree growers and then resell or may act as an agent, organising direct transactions between tree growers and buyers.
  • Plantation Establishment
    Assist in establishment of plantations by organising forest supplies and contractors.
  • Managing Forests
    Plant and manage forests for a landholder on a contract basis.
  • Harvesting and Transport
    Co-ordinate and supervise the harvesting and transport of timber to buyers, ensuring this is done in accordance with prescribed forestry practices.
  • Holding Depot
    Establish and operate holding depots for timber as required.
  • Value Adding
    May purchase members timber and process it, either through its own facilities or with a joint venture partner.

Links

The following lists websites where additional Agroforestry information can be found. Many of these websites also contain links to other Agroforestry related websites.

Association of Societies for Growing Australian Plants. (ASGAP)