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The

Report

No. 68: Integrating Farm Forestry 
and Biodiversity

The full report

This is a summary of a published RIRDC report Reconciling Farm Forestry and Biodiversity (AAC–4A,99/166,available December 1999) by Dames and Moore NRM/ FORTECH, phone 02 6248 6900,
fax 02 6248 6999, email cbr_for@dames.com.  You may view or download this report from the RIRDC web page at www.rirdc.gov.au/pub/cat/contents.html

Summary

Although biodiversity conservation and timber production are sometimes seen as mutually exclusive goals of farm forestry, there are examples of where they have proved complementary.

Such complementarity could be promoted through six mutually reinforcing strategies:
 

• innovative plantation designs
• codes of practice
• increasing landholder interest
• R&D
• cost-sharing
• the provision of enabling policies by government.

Integrating farm forestry and biodiversity

Farm forestry has the potential to address many ills in the agricultural landscape:rising watertables,declining biodiversity,soil acidity, diminishing farm income,to name a few.But addressing any one of these problems with trees won ’t necessarily do anything for the others. Without appropriate legal and institutional frameworks,adequate information,planning and design there may,in fact,be conflicts between different tree-planting objectives.

Recognising this,in 1997 the RIRDC/LWRRDC/ FWPRDC Joint Venture Agroforestry Program commissioned a consultancy firm,Dames & Moore,to investigate practical ways of integrating two farm forestry objectives that are sometimes seen as mutually exclusive: biodiversity conservation and the commercial production of wood fibre and other products.

The consultants examined:
 

• the legal and policy framework for protecting biodiversity;
• scientific evidence concerning biodiversity in commercial farm forests;and
• anecdotal evidence from existing farm forestry operations.


The outcome was a discussion paper on the practical integration of farm forestry and biodiversity.It concluded that while more research is needed,there are many potential ways of ensuring that biodiversity values are maintained and enhanced,even when the primary farm forestry objective is commercial production.

The scope for conflict

There is certainly plenty of scope for conflict between commercial farm forestry and biodiversity.For example,remnant native vegetation might be cleared for the installation of timber plantations.The pesticides and herbicides used in the management of commercial plantations might reduce biodiversity in soils, vegetation and streams.At least one commonly used plantation species,radiata pine,is known to invade native forest.And the relative ease with which eucalypt species hybridise may lead to exotic eucalypt plantations ‘contaminating ’ the genetic stock in adjoining native forests.

It is also possible that laws designed to protect biodiversity or prevent the clearance of native vegetation —summarised in Table 1 —may act as a disincentive for the development of farm forestry.These laws operate in different ways in different states and have different implications for farm forestry.Nevertheless,the consultants concluded that in general it appears that laws and policies in most states and territories do not lead to unfair disincentives for farm forestry plantings.The possible exception to this is New South Wales:the biodiversity-related laws in that state involve time-consuming application procedures that some forest growers consider an impediment to farm forestry.

Trade-offs

The consultants identified a spectrum of trade- offs between the goals of commercial timber production and biodiversity conservation (Figure 1).At one end are large,monoculture plantations managed intensively for timber.At the other end are mixed species plantations, often on a small scale,with little active management.In between are plantations where aspects of both goals might be accommodated.

The evidence of benefits

As part of the consultancy,CSIRO scientists conducted a literature review of scientific studies related to biodiversity in farm forestry.They found that research relevant to this topic is sparse and generally inconclusive.For example,few studies compare the biodiversity value of farm forestry on cleared agricultural land with that of land used for traditional agricultural enterprises. This largely reflects the fact that farm forestry is only a relatively recent phenomenon in Australia and points out a major need for further research.

 Figure 1:Trade-offs between commercial farm forestry and biodiversity goals





 Table 1:Endangered species and native vegetation legislation in Australia






Opportunities for enhancing biodiversity in farm forestry

Nevertheless,the consultants identified a number of situations where biodiversity conservation and commercial production are likely to be complementary. Plantations may enhance re-establishment of diverse natural vegetation:commercial plantings of Queensland maple (Flindersia brayleyana )and red cedar (Toona ciliata )have been found to support a complex understorey, with more than 350 species found in some plantations.Hoop pine (Araucaria cunninghamii )plantations have also been found to support a wide range of native plant species. Plantations on farms can maintain soil biodiversity:some studies have demonstrated a greater level of microbial and microarthropod activity in the soil under trees and farm forestry plantings than in soil on cleared or unplanted land.

Plantations on farms can maintain stream biodiversity:trees planted on streambanks or in recharge areas can assist in controlling rising saline groundwater,limiting erosion and capturing nutrients and bacterial pollutants. In this way they contribute to the health of watercourses and help maintain stream biodiversity.

Farm forestry can provide income from land managed for habitat:carefully designed farm forestry can integrate the periodic harvest of selected and specially managed trees with the provision of habitat along riparian zones,in wildlife corridors or in remnant native vegetation,thereby helping to fund on-farm nature conservation efforts.

Plantations provide greater habitat structure: tree plantations provide more diverse habitats – both above and below ground – than do other agricultural land uses such as annual crops and pastures.The vertical structural component,for example,may assist the return of certain tree- dependent birds and mammals.

Greater biodiversity can contribute to farm productivity:there is increasing evidence that biodiversity performs ecological functions that contribute to overall farm productivity.For example,siracid wasps in the New England Tablelands,which feed and breed on acacia windbreaks planted around paddocks,have been shown to reduce the population of scarab larvae in pastures.

Mixed plantations can produce high quality sawlogs:understorey and nurse crop species can help ensure that commercially important species such as Eucalyptus maculata or Acacia melanoxylon achieve the required height, straightness and diameter needed to optimise the production of high-value timber from farm forestry.

Reconciling commercial farm forestry and biodiversity

Not all commercial farm forestry plantings will make a contribution to biodiversity conservation.However,the biodiversity discussion paper highlights the potential to expand the areas of overlap between commercial and biodiversity goals.It identifies three key ingredients for this to happen:
 
• the importance of research and development in identifying innovative solutions;

• the role of governments in providing enabling policies based on the sharing of costs and returns;and

• the explicit recognition of biodiversity enhancement as a goal of farm forestry.


The paper outlines a number of key elements to maximise the overlap between biodiversity and timber production goals.

Innovative designs

The two objectives of commercial farm forestry and biodiversity conservation may be achieved on the ground through innovative farm forestry designs and management regimes.For example, habitat ‘patchiness ’can be promoted by mixing species and planting at time-intervals that provide a mix of age classes in close proximity.

This could be done based on varying site quality:for example,habitat plantings could be integrated into property management plans so that commercial species are planted and managed on sites of high quality and biodiversity plantings are located on sensitive or low productivity sites.

Another option for regions where thinnings have low economic returns might be to use nurse trees that can be felled or killed and left standing,thereby providing an extra habitat component.This technique has been trialed successfully in South Australia for A. melanoxylon and E.globulus production using A.mearnsii and A.saligna as nurse trees,of which half are killed and left standing at four years and the remaining at eight years.The dead trees provide habitat for a range of insects,which in turn feed bandicoots and birds.

Are there other management or planning options that promote both production and biodiversity objectives?The biodiversity discussion paper suggests that further research may well reveal more innovative approaches.

Codes of practice

Codes of practice are increasingly seen as an important way of promoting the sustainability of both plantations and native forest management. The development of such codes provides an opportunity for forest growers to develop approaches to management that maximise biodiversity values consistent with commercial goals.For example,they could address:
 
• the recognition of biodiversity values in plantation management plans;

• the use and management of indigenous species in headlands,buffers,filter strips, the riparian zone and areas within plantations unsuited to plantation species;

• the management of plantations to protect biodiversity values,with specific mention of practices for the use of herbicides, pesticides,fertilisers,fire and harvesting equipment;

• the design and management of plantations to protect locally occurring rare and endangered species;and

• the selection of species and provenances to preserve indigenous genetic diversity where this can be consistent with commercial objectives.


The adoption of voluntary codes of practice as a mechanism for creating linkages between trees on farms and biodiversity conservation would have several advantages.For example, by being proactive,growers would demonstrate compliance with existing biodiversity policies, regulations and community expectations and thereby avoid direct intervention by governments.

Increasing landholder interest

Demonstrating the potential for joint commercial and environmental benefits from farm forestry is vital to increasing landholder interest in farm forestry.Property management planning,a practice that is being embraced enthusiastically by farmers,is one potential mechanism:it provides a framework for considering plantation development as part of a sustainable production strategy.In particular, it can help maximise the contribution of farm forests to biodiversity by focusing on location and design of the plantings in relation to remnant vegetation and other relevant factors.

For farmers to use property management planning to best advantage,information on the potential role of trees in both production and conservation must be available – which means that the provision of extension services is a key element.Enhanced bioregional planning, which could be promoted through catchment management plans,would help individual landowners contribute to biodiversity conservation at the regional level.

Research

There is a clear need for more research into the role of planted farm forests in biodiversity conservation.Two workshops involving biodiversity researchers undertaken in the preparation of the paper identified a number of R&D priorities.They concluded that R&D should aim to:
 
• further develop designs that maximise biodiversity impacts and quantify the trade- offs;

• identify factors that may influence the effectiveness of designs and management regimes in different bioregions;and

• utilise existing farm forests to identify biodiversity effects.

Cost-sharing

The conservation of biodiversity is an issue of public concern,yet by integrating biodiversity objectives with commercial farm forestry we may be asking landholders to shoulder the bulk of the costs.What are the public and private costs and benefits of such integration? The identification of these,and the provision of public funds to share the costs of biodiversity conservation,would encourage landholders to pursue biodiversity objectives while developing their farm forestry strategies.

The role of government

Governments could play a role in many facets of farm forestry development.But the paper suggests that government should concentrate on producing enabling policies that promote the practical integration of biodiversity goals into farm forestry.Such policies might include:
 
• sharing the R&D costs required to develop innovative farm forestry designs;

• assisting the development of multi-skilled extension officers with a sound understanding of the role of trees and farm forests in farm landscapes;

• promoting the adoption of property management planning and providing frameworks which promote the inclusion of biodiversity conservation into property management plans;

• improving bioregional planning to identify priorities for biodiversity conservation; • identifying the public and private benefits of farm forests,particularly those arising from the promotion of biodiversity;and

• developing and applying cost-sharing principles for the provision of funding for farm forestry investments.

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Last updated: 17 December 1999 Copyright © RIRDC
http://www.rirdc.gov.au/pub/shortreps/sr68.htm