Dorrigo Nursery

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Design and Establishment
of Shelterbelts

  • The On-Farm Benefits of Timberbelts

  • Designing a Timberbelt to Capture Multiple Benefits of Shelter, Timber Production and Nature Conservation.

  • Species Selection

  • Factors to Consider when Designing a Timberbelt


  • Shelterbelts are a valuable tool to landholders for the enhancement of environment, productivity and natural habitat.

    A timberbelt is a multi purpose shelterbelt which incorporates timber production with other benefits.
    It is not a substitute for the woodlot if single purpose timber production is the aim.
    However, a timberbelt is a viable option for producing timber which does not require the devotion of large areas of land to a single purpose and which can provide a range of other on- farm benefits simultaneously.
    A carefully designed timberbelt will produce timber while offering the benefits of shelter to stock and crops.
    Good shelter on farms can actually modify and control the farm climate by, not only, reducing wind speed but also by creating changes in the microclimate within a paddock.
    Microclimate is the climate near the ground, in which animals and plants live and, by effecting this, shelter can bring changes that benefit both stock and crops.

    The On-Farm Benefits of Timberbelts

  • Protection of Crops and Pasture: Strong winds can reduce plant growth by increasing evaporation from plants and soil, making them more susceptible to moisture stress problems.
    Strong wind will also damage plants by causing sand blasting, leaf rubbing or stripping and tearing of leaves.
    By reducing all of these factors timberbelts can improve stock and crop yields.
  • Decreasing Wind Erosion: Timberbelts will lower wind speeds to a level where soil erosion is minimised.
    The introduction of deep rooted perennial plants also assists in estabilising the soil on these areas.

  • Protection of livestock: Extremes of temperature create inefficient growing conditions for livestock as animals will be required to use extra energy just to maintain basic metabolic processes.
    This reduces the energy available for increasing body weight or producing milk or wool.

  • Timber Production: By planting a multi row timberbelt including commercial timber species, a timberbelt can be managed to produce on- farm timbers and high value clearwood for sale.

  • Nature Conservation: By using a diverse range of species a timberbelt can provide habitat for a range of native bird and animal species.
    The value to wildlife can also be increased by designing the timberbelt to link any native remnants on the farm and act as a wildlife corridor between them.

  • Lessening the Danger of Grass Fire: By reducing the wind speed a timberbelt has the potential to slow the rate at which a fire can spread, thus making it easier to control.

    Designing a Timberbelt to Capture Multiple Benefits of Shelter, Timber Production and Nature Conservation.

    Two Rows
    Three Rows
    Four Rows

    The following suggestions for design, taken from
    Farm Forestry Clearwood Production, include both shelter and timber trees.
    The shelter rows ensure that one or more rows of trees will be retained for shelter and nature conservation after the timber trees have been removed from the other rows.
    Following harvest, the timber species can be reestablished while the structure and conservation benefits of the shelterbelt remain intact.
    Remember these designs are suggestions only, they can be adapted to suit individual situations or new designs created to fit in your farm.

    Two Rows

  • Timber and shelter trees planted at even spacing in separate rows.
  • With this model you would plant all trees at 2m spacing
    The shelter row would be left as such and the timber species could be selectively thinned by year 6 to leave the best stems for clearwood production.
    This would mean that the timber trees would be left at a final spacing of 4m to maturity (250 trees/km).

    S      S      S      S      S      S

            T      T      T      T      T      T
    SPACING BETWEEN ROWS 2- 3m


  • Timber planted in clumps of 3 in one row and shelter trees planted at even 2m spacing in the other row.

  • With this model the shelterbelt would be retained at 2m spacing while the timber trees would be thinned to the best tree per clump for clearwood production.
    This would leave the timber trees at an average spacing of 4m (250 trees/km).

               S         S         S         S         S         S

    TTT     TTT     TTT     TTT     TTT     TTT
    1m WITHIN CLUMP, 2m BETWEEN CLUMPS


    Three Rows

  • One row of shelter species evenly spaced at 2m, Two rows of timber trees in clumps of 3.
    The row of shelter trees would remain at 2m spacing with the timber trees being thinned by about year 6 to one tree per clump (500 trees/km), depending on form.

               S           S           S           S           S          

    TTT       TTT       TTT       TTT       TTT       TTT

    TTT       TTT       TTT       TTT       TTT
    1m SPACING WITHIN CLUMP, 3- 4m BETWEEN ROWS


  • Timber trees planted in clumps of three with shelter species planted between clumps.

  • The shelter trees are planted in 2m gaps between clumps.
    Within clumps timber trees are planted at 1m.
    Timber trees will be then thinned to one tree per clump leaving an average 4m spacing within the remaining timber trees (750 trees/km).
    This model could also be used planting 2 trees per clump.
    T       T       T       S       T       T       T

    T       S       T       T       T       S       T

    T       T       T       S       T       T       T
    SPACING BETWEEN ROWS 3- 4m

    Four Rows

  • Timber and tall shelter trees planted alternatively at 2m spacing in three rows with one row of shrub species on the outside.
    No thinning of timber trees occurs in this model, all timber trees are form pruned, but only those with good form go on to be pruned (750 trees/km).
    Shelter trees in the timber row can be selected and cut for firewood.

    S       S       S       S       S       S

             T       S       T       S       T       S

    T       S       T       S       T       S

             T       S       T       S       T       S
    3- 4m BETWEEN ROWS

    Species Selection
    The first thing to do when planting a shelterbelt is to identify its purpose.
    Is it for protection of stock and crops, for habitat values, timber production or to capture all these benefits?
    Choice of species will come once this has been decided as you will then pick a range of species to attract birds or produce timber, provide dense or permeable shelter etc.


  • Timber Species Suitable for an Exposed Site: >
    Botanical Name Common Name Timber Uses
    Acacia melanoxylon Blackwood cabinet
    Eucalyptus andrewsii New England Blackbutt sawlog
    Eucalyptus dalrympleana Mountain Gum sawlog
    Eucalyptus dorrigoensis Dorrigo White Gum pulp
    Eucalyptus fastigata Brown Barrel sawlog
    Eucalyptus nitens Shining Gumsawlog, pulp, veneer
    Eucalyptus nobilis White Gum sawlog, pulp, veneer
    Eucalyptus saligna Blue Gum sawlog, cabinet, fuel, veneer
    Eucalyptus viminalis Manna Gum sawlog, pulp, fuel
    Grevillea robusta Silky Oak cabinet, veneer


  • Shrub and Shelter Species Suitable for an Exposed Site: >
    Botanical Name Common Name Comments
    Acacia irrorata Blue Skin Wattle quick growing
    Acacia floribunda White Sally Watttle quick growing
    Banksia integrifolia Coastal Banksia bird attractant
    Banksia spinulosa Heath Banksia bird attractant
    Callistemon salignus Paperbark Bottlebrushbee & bird attractant
    Casuarina cunninghamiana River Oak adaptable
    Hakea salicifolia Common Hakea bird attractant
    Leptospermum polygalifolia Tea Tree Handles wet feet


    Factors to Consider when Designing a Shelterbelt

  • Height: the higher the timberbelt the greater the area that will be protected.
    A timberbelt can reduce wind speed up to 25 times the height of its trees on level ground with the maximum benefit being in the zone 5 to 15 times the tree height away from the timberbelt.

  • Length: because wind swirls around the end of a timberbelt, it is best to make the belt as long as possible.
    If a timberbelt is too short the wind will be deflected around it at increased velocity.
    A minimum length of 200m is recommended with few gaps as these can concentrate and funnel winds.

  • Permeability: the permeability of a timberbelt affects both the degree and extent of shelter.
    A permeable timberbelt is most suited to provide general protection in a paddock as, even though they let wind filter through them, they provide a larger zone of protection than dense timberbelts.
    Dense timberbelts are best when you want a small area of high quality shelter as they block wind and create a greater reduction in wind speed.
    However, this reduction is restricted to a narrow zone and may also cause more turbulence down wind.
    Tree species and the number of rows will both effect the permeability of a timberbelt.

  • Orientation: firstly it is important to identify which winds do the most damage and locate timberbelts at right angles to these.
    The placement of timberbelts can be assisted by observing stock and their movements in times of extreme weather conditions.
    A straight timberbelt will generally only provide good protection from winds at right angles to it.
    It is good to consider, in relation to this, establishing a network of timberbelts that might meet at right angles to maintain shelter as the wind shifts.

  • Number of Rows: single row timberbelts are often not desirable as any death which occur within the timberbelt will create a gap leading to wind funneling.
    Multiple row timberbelts on the other hand, allow you to use tall trees with lower shrubby species.
    Generally the effectiveness of a timberbelt will increase as the number of rows increases from one to five.
    Multiple rows can also provide permeability and height by using one or two rows of tall trees.
    By including shrub species in one of the rows the habitat advantages of the timberbelt are also increased.



    Suggested further reading: A Haven From Storm and Drought (GA Ltd, RIRDC & LWRDC 1997).


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