Pears, like most deciduous fruit trees require a certain amount of winter chill in order to break dormancy in spring and and begin growth and flowering.

Why is winter chill important?

How is winter chill measured?

What are the winter chill requirements for pears?

Further information

Why is winter chill important? 

If sufficient winter chill is not received it can result in delayed and uneven leaf and flower development and subsequently poor fruit set. This can affect yield, fruit quality and harvest duration.  

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How is winter chill measured? 

The accumulation of winter chill is measured through a number of models. The three most common models are the 7.22^oC and under model, the 0-7.22^oC model and the Utah model.  

The 7.22^o C and under model is the traaditional model used to record chill units. In this model, each hour below 7.2^o C is equal to one chill unit.

The  0-7.22^oC model records one chill unit as an hour between 0 and 7.2^o C. An hour spent below or above 7.2^o C is recorded as zero chill units.

The Utah model records chill in 'Richardson'  Chill Units. This model recognises the influence that different temperatures have on chill. For example temperatures between 2.5-9.1^oC are considered to attribute the most towards the completion of dormancy and are therefore given the value of one chill unit for each hour spent in that range. Lower and higher temperatures can have a negative effect on chill unit accumulation and are assigned values accordingly. The following table outlines the calculation of chill units using the Utah Model.  

                                                                               Table 1: Calculating Chill Units using the Utah Model

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Winter Chill requirement for European pears

Pears generally require between 500 and 1500 hours of chilling. Specific varieties differ in their chill requirements.

Defiinitive data on the chill requirements of pear varieties in Australia are difficult to find. However, the varieties grown commercially in Australia can be roughly divided into those requiring, high, medium or low chill (Campbell 1995).

High Chill - Williams, Buerre Bosc, Winter Nelis, Comice, Lemon Bergamot

Medium Chill - Packham's, Josephine

Low Chill - Corella

For more information on the chill requirement for pears see further information.

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How can I determine the winter chill in my area?

An estimate of winter chill for an area can be determined through using this simple Chill Unit Calculator provided by the Department of Primary Industries, Victoria (external link).

Further information

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

Measuring Winter Chill

For information about the importance of winter chill and its measurement please visit any of the folllowing sites

•  Chill Units of Stone Fruit - Victorian DPI Agnote (external link).
• Winter chilling recorded in Western Australia - Department of Agriculture Western Australia Farmnote (external link). 

Winter chill requirement for pears

For guidance on the chilling requirement of pear varieties in Australia

• Winter Chill - Apples and Pears for Warmer Districts - Conference presentation by Dr J Campbell (external link).
• European Pear Varieties - NSW Department of Primary Industires AgFact (external link).

International Resources

• Chilling accumulation: its importance and estimation - Department of Horticultural Sciences, Texas A&M University (external link).

References

Campbell, J. (1995). ' Winter Chill! - Apples and Pears for Warmer Districts'. in Proceedings of the Sixth conference of the Australasian Council of Tree and Nut Crops , Lismore, NSW, September 11-15 Retrieved January 2009 from http://www.newcrops.uq.edu.au/acotanc/papers/campbel1.htm

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One of the most important factors that will determine the success of an intensive pear orchard is the site it is planted on. When establishing an orchard it is important that a number of factors are considered by the growers to minimise any potential site limitations to growth.

The following are a number of factors that need to be considered when planning the orchard.

Soils

Climate

Aspect

Slope

Frost susceptibility

Wind

Water availability

Further information

Soils

Soils are an important consideration for pear plantings . It is important to understand soil characteristics and site history before planting in order to correct any problems. Soils should be assessed through soil pits and soil sample analysis as well as local soil maps.

                                                                               Figure 1: Inspecting a soil pit in an orchard.

Soil texture

Soil texture refers to the proportion of sand, silt and clay sized particles in the mineral fraction of the soil. This is important as it influences the water holding capacity of the soil, the ability for water to move through the soil as well as its fertility.

Lighter soils have a high sand content relative to clay and have poor water holding capacity as well as lower fertility. Heavy soils are high in clay content and will generally hold more water and are more fertile. Heavier soils can be prone to waterlogging.  

Clay loam to sandy loam soils offer the best potential for pear production.

Soil structure

A good soil structure is important for drainage of water and the movement of air through soil. Soil structure is influenced by texture and soil particle aggregation. Soil particle aggregation can be improved through the addition of organic matter (cover crops and mulching) which helps bind soil particles together. Tillage can also improve soil structure, however this is often only a temporary effect.

Depth

Soils should have atleast 60cm good quality topsoil. Topsoil depth can be improved by hilling up of treelines (mounding). This will improve depth as well as provide a gradient for surface run-off and seepage into th centre of the row.  

Drainage 

Internal drainage characteristics of the soil is one of the most important factor to ensure orchard longevity. Whilst pears are more tolerant of poorly drained soils than other fruit, waterlogging can impact negatively on production and even result in tree death.

Soils should be well drained and not prone to waterlogging. In some soil types underground tile drainage may be necessary to safeguard trees from waterlogging.

Nutrient levels

It is important to take a soil test to determine the soil nutrient levels at potential planting sites. This will indicate whether any ammendments are required. 

Information on soil testing can be found in further information.  

pH 

Soil pH should ideally be between 6.0-6.5 anything above or below this can result in nutrient deficiencies. Alkaline soils (pH <6.0), particularly those with high lime or bicarbonate content can result in iron chlorosis (often referred to as lime induced chlorosis), particularly on quince rootstocks.  

                                               Figure 2: Assessing soil pH in an orchard.

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Climate

Pears generally require between 500-1500 hours of chilling. Pears grow well in areas with warm and hot summers and low humidity.

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Aspect

A north or north easterly aspect is best for providing maximum sunlight during winter months. Slopes facing south are colder and more frost prone.

                                                                                  Figure 3: Orchard planting scenarios

In the scenario in Figure 3 the orchard at site A is a warm location and will recieve more sun as it is North facing. It will be less prone to spring frosts as the cold air will drain to the lower lieing area (site B). Site B at the bottom of the valley will be the most susceptible to spring frosts because of the cold air draining to it from higher up the slopes. Site C is colder and will warm up more slowly than at site A because it is south facing.

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Slope

Gently sloping sites are best. Steep slopes can pose significant safety issues particularly for machinery and equipment.

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Frost susceptibility

Pears are highly susceptible to spring frosts. The financial risk associated with crop loss in an intensive orchard is high so minimising crop loss through frost damage is important. Initially growers need to avoid planting in frost prone areas. Planting sites need to also have good air drainage to prevent accumulation of cold air (avoid planting at the bottom of slopes or in hollows).

Orchards need to be established with considerations for frost protection including warning systems and the installation of frost fans or sprinkler systems.

Figure 4: Frost fan in a stonefruit orchard.

Management of the orchard floor is also important to minimise frost damage. All inter-rows should be slashed as close to the tree line as possible and weeds in tree lines sprayed. The aim is to have most of the orchard soil exposed to warming sunshine during the day so that heat accumulated can be released in the early mornings to reduce frost risk.

For more information on frost and its management please see further resources.

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Wind

Wind can damage fruit and reduce fruit quality, increase evaporation, affect pollination and damage newly planted trees. Support structures for trees should be installed prior to or soon after planting to minimise root damage in young trees.  

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Water availability

Intensive orchards need secure access to water for irrigation, spraying and possibly for frost protection and evaporative cooling. Good delivery infrstructure is essential. It is often recommended that growers ensure they can have atleast six megalitres of water per hectare of orchard. Go to the irrigation page for further information.

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Further information

These Australian and international sites may be useful for growers, however they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources:

Soils

• Sampling soils for flower, fruit, grape and vegetable production: Victorian Department of Primary Industries AgNote (external link).
• Understanding the soil : Queensland Department of Natural Resources and Water factsheet (external link).
• Soil physical properties - texture and structure : Victorian Department of Primary Industries AgNote (external link).
• Water infiltration and drainage in soils : Victorian Department of Primary Industries AgNote (external link).
• Soil types, structure and condition : New South Wales Department of Primary Industries information (external link).

Frost

• Frost, its nature and control : Victorian Department of Primary Industries AgNote (external link).
• Frost protection: fundamentals, practice and economics : Publication by the Food and Agriculture Organisation of the United Nations  (external link)

International Resources:

• Pennsylvania Tree Fruit Production Guide : Resource developed by the Pennsylvania State University (external link).
• The Pear Production and Handling Manual has been produced by the University of California. It provides information about site requirements for pears. You can purchase this book directly through this website  (external link).

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 The planting system is the integration of tree arrangement, planting density, support systems and training schemes.

There is no one planting system to suit all situations. Factors such as climate, soil, variety, rootstock, quality of nursery trees, management regimes and economic conditions will determine the optimal combination for each orchard.  

Essentially fruit production is highly dependant on light interception and distribution in the canopy. A well planned orchard should intercept 70-80% sunlight falling on the land.

This means that the planting system needs to have a combination of components that ensures optimal light interception and distribution from an early stage. 

Tree Arrangement

Planting Density

Support Systems

Tree Training

Further information

References

Tree Arrangement

The goal of tree arrangement is to maximise the efficiency of production by balancing the interception of sunlight with the efficiency of operation (Hoying and Robinson 2006). Trees can be arranged in various ways ranging from single rows through to multiple row or bed systems with occasional drive alleys.

The most common tree arrangements for intensive pear production systems are in single or double rows (eg. Open Tatura Trellis). 

 Figure 1 & 2: Pear trees arranged as a single row (left) and double row in an Open Tatura Trellis system (right)

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Planting Density

Tree density is one of the most important factors that influences the production of fruit in an orchard - particularly in its early years.

Many studies with various varieties and rootstocks have shown that increasing tree densities will result in earlier production of pears and increased yields. This is because higher tree densities result in a closed canopy and higher light interception earlier in the life of the orchard when compared with low densities (Kappel and Brownlee 2001, Balkhoven-Baart et al. 2000).

The relationship between yield and density does not remain linear however. Whilst cumulative yields can double in going from low to high density plantings, the move to very high and ultra high density results in a less significant increase in yields. Often these increases do not justify the additional costs of establishment. Balkhoven-Baart et al. (2000) demonstrated this in apples where moving from 6000 trees/ha to 10000 trees/ha gave an increase in fruit production of 15%. This is compared to the 40% increase from 3000 trees/ha to 6000 trees/ha.

The classification of what constitutes a high density orchard varies between production regions. For the purpose of this site densities are defined as follows;

• Low density = <1000 trees/ha
• Moderate density = 1000-2500 trees/ha 
• High density = 2500-4000 trees/ha
• Very high density = 5000-8000 trees/ha
• Ultra high density = > 8000 trees/ha

Figure 3: Very high density 'Conference' pear orchard in the Netherlands (9000 trees/ha)

What is the optimum tree density?

There are a number of factors that will determine the optimal tree density for an intensive pear orchard. Fundamentally within row spacing (and therefore tree density) needs to be calculated based on the vigour of the scion variety and rootstock and the soil quality.

Where the combination of rootstock x scion variety x soil results in vigorous growth it is best to look at wider spacings and therefore lower densities. Where there is access to more dwarfing rootstocks (such as Quince C) planting distances can be reduced (increasing tree density). 

The decision about planting density is also largely dependant on economic considerations such as establishment costs and likely returns. Whilst it is recognised that higher planting densities will result in earlier and higher yields, many pear production regions are settling on densities of around 2500-4000 trees/ha as the most suitable both production and cost wise.

Calculating spacing and density

The tables below provide a ready guide to planted tree densities at different tree and row widths based on different training systems used for pears. Please note these numbers are based on a planted hectare, no allowance has been made for headlands. The row widths for the Double Row systems is based on row centre to row centre and therefore is accurate irrespective of actual gap between the 2 rows that form each double row.

If you wish to calculate tree numbers per planted hectare for your own spacings the following formulas can be used.
 
Single row systems   =                10000                       (10,000 square metres = 1 hectare)
                                 (row width x in row spacing)

Example                   =    10000          = 10000   =  1441 trees/planted hectare
                                  3.75 x 1.85           6.94

Table 1: Density and spacing for single row high density/trellis systems 

                                                                   Between Tree Spacing (m)                               

Table 2: Density and spacing for double row systems (eg. Open Tatura Trellis) 

                                                                   Between Tree Spacing (m)                               

Table 3: Density and spacing for Y shaped systems (eg. Traditional Tatura Trellis)

                                                                   Between Tree Spacing (m)                               

      (Source: Paul James, Rural Solutions, SA)

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Support Systems  

Support or trellis systems are required in most intensive production systems to support the crop load. Often trees in intensive production systems are producing fruit well before the tree's own support system is strong enough to hold the crop.

The choice of support system will be influenced by the density and training systems chosen and the availability of materials. It is easier to install an adequate support system at the beginning of an orchard than to replace or repair an inadequate system that fails when trees begin to bear significantly.

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Tree Training

The primary objective of pear tree training is to direct tree growth and develop a strong tree framework that will support quality fruit production. In particular, proper training of pear trees opens up the canopy to ensure maximum light interception and distribution and therefore quality yields.

Tree training is particularly important in mature orchards where canopy shape affects the light distribution within the tree canopy. If the intercepted light is not evenly distributed throughout the tree canopy, shading can occur. This can inhibit flower bud development, fruit set and fruit colour.

It is important that trees are trained and managed so that they allow for maximum light interception and distribution throughout the canopy, and reduce the risk of heavy internal shading.

What is the best training system?

Around the world pears are trained in a variety of systems over a range of densities. Whilst many systems are technically sound, it is often a question of costs, management requirements and fruit returns which influence whether a system is actually the most viable option for an orchard.  

Training systems need to be able to accommodate

• high, early fruit production
• good light penetration to all parts of the tree
• good control of the height and spread of trees
• easy access to fruit for harvest

Often there can be confusion about the definitions of training systems, particularly between those that appear to apply the same pruning concepts and methods. 

Generally tree training systems for intensive pear production can be categorised as

• Systems derived from central leader - conical or pyramidal shaped trees
• Double leader systems - single trees with two leaders (simulating higher densities)
• Palmette systems - basically central leader trees with scaffolds in the plane of the row only
• V or Y shaped systems - inclined canopies that improve light interception 

Examples of these training systems are provided in the Planting System Examples page.

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Further Information

These sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linked from this page you are leaving the intensivepear.com website

International Resources

Intensive Pear Orchard System Development

• The Pear Production and Handling Manual has been produced by the University of California. It provides detailed information about various pear production systems with specific detail on the training and pruning requirements for each. You can purchase this book directly through this website (external link).

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References

Balkhoven-Baart, J.M.T., Wagenmakers, P.S., Bootsma, J.H., Groot, M.J. and Wertheim, S.J. (1998). "Developments in Dutch apple plantings." Acta horticulturae 513: 261-270

Hoying S.A., Robinson T.L. (2006).“The apple orchard planting systems puzzle.”  Acta Horticulturae 513: 257-260. 

Kappel F., Brownlee, R. (2001). "Early performance of 'Conference' pear on four training systems." Hortscience 36: 69-71

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 Choosing a rootstock is one of the most important decisions when planning an intensive pear production system. Rootstocks play an integral role in influencing

• tree vigour
• growth habit
• cropping
• resistance to pest and diseases, and
• tolerance to unfavourable conditions in the growing environment.

The performance of a rootstock is influenced by a combination of factors including the choice of scion variety, the quality of rootstock material, grower management practices and the growing environment. It is therefore important that growers have a good understanding of each of these factors as well as rootstock characteristiscs to ensure they choose a combination that provides maximum potential.

Rootstocks for intensive pear production

Quince Rootstocks

Pear (Pyrus) Rootstocks

Availability in Australia

Further Information

References

Rootstocks for intensive pear production

Most European pear species (Pyrus communis) around the world are currently grafted on either clonal (vegetatively propogated) or seedling rootstocks of the Pyrus species (Pyrus communis, P. calleryana, P.pyrifolia, P. betulaefolia) or on quince (Cydonia oblonga).

In the case of intensive production systems, the objective is to use a rootstock that restricts tree vigour, induces early cropping (ie. is precocious) and results in a high yield efficiency. Yield efficiency is usually measured as yield per unit of tree size (trunk cross sectional area).

Quince Rootstocks

Almost all quince rootstocks are clonal and they have been used for pear production for many years, particularly in Europe. The most commonly used are

• BA29
• Quince A
• Quince Sydo
• Quince Adams
• Quince C
  

There have been many evaluations carried out with quince rootstocks. Whilst there is often some variation in results between sites and scion cultivars, generally BA29 is considered the most vigorous followed by Quince A and Quince Sydo (both approximately 75% of seedling) and then Quince Adams. Quince C is the least vigorous at approximately 60% of seedling.

Quince C and Quince Adams have the highest yield efficiency compared to BA29, Quince A and Sydo (which are all similar).

Figure 1: 'Conference' nursery trees in Belgium. On the left trees are grafted onto Quince C and the right is Quince A.

In more recent years three other promising quince clones have emerged - Quince EMH (developed at East Malling), C132 (a selection from the Caucasus region of Russia) and Eline® (a Romanian selection sourced from Fleuren Nurseries in the Netherlands). These rootstocks are generally considered to perform similarly to Quince C in terms of vigour control and yield efficiency (Johson et al 2005, Maas 2006). However in some trials they have exhibited traits that may make them more attractive than Quince C such as improved fruit size (EMH and C132) and reduced russetting (Eline®) (Maas 2006).

See the Gallery for more images of Quince rootstocks

Management challenges

Whilst quince rootstocks provide considerably good vigour control there are still key management challenges associated with their use. 

One major issue  is the incompatibility of quince with many important European pear scion cultivars ('Williams', 'Buerre Bosc', 'Packhams'). This can be overcome with the use of interstems of compatible cultivars such as 'Buerre Hardy' or 'Comice'. 

Quince rootstocks are also susceptible to lime induced chlorosis. Lime induced chlorosis is often assosciated with soils that have high pH and high ligh content. Generally in areas where this is a problem  (such as in many parts of Southern Europe) the more vigorous of the quince rootstocks (such as BA29) or Pyrus rootstocks are preferred.

Limited winter hardiness is also an issue with quince rootstocks, and this has limited their use in areas that suffer severe winters, such as in the US Pacific North West and parts of Eastern Europe. This should not be a major issue in Australia's pear production regions.    

The biggest challenge growers in Australia may face with quince rootstocks is their susceptibility to drought stress. This is potentially more serious on the less vigorous Quince C and Adams. If quince is to be adopted in production systems it is important that growers closely monitor tree performance and ensure optimal irrigation management.

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Pear (Pyrus) rootstocks

Whilst quince is the preferred rootstock in Europe, Pear (Pyrus) rootstocks are still heavily relied on elsewhere. This is largely due to unsuitable growing conditions for quince in these areas. The majority of Pyrus rootstocks used are seedling which often results in very vigorous growing trees, an undesirable trait for intensive production. Trees grown on seedling rootstock can also be highly variable.

In Australia Pyrus calleryana D6 (D6) is currently the most commonly used rootstock for commercial pear production. However, it is an excessively vigorous seedling rootstock that produces very large trees and is unsuitable to modern systems of intensive pear production.

There have been some clonal pyrus rootstocks developed for intensive production and these are outlined below.

OHF series

The Old Home x Farmingdale (OHF) series of rootstocks originated in the United States. OHF 40, 51, 69, 87, 217, 282 and 333 are the major rootstocks in this series. Evaluations from different areas have shown a range of vigour and yield efficiency. It is generally accepted however that these rootstocks are too vigorous for intensive production. Some of these rootstocks have been introduced into Australia, however no rigorous evaluation has occurred and they are not readily available from nurseries.

Several trials are underway at the Mid-Columbia Agricultural Research and Extension Center in the US to screen for a dwarfing rootstock from the Horner series. This is a pyrus series developed from crosses of ‘Old Home x Farmingdale’ rootstocks (Mielke and Smith 2002, Mielke and Sugar 2004).

BP1

BP1 originated in South Africa and is reported to have a vigour similar to Quince A and BA29 ( 75% of Pyrus Calleryana) and have a good yield efficiency. There are no reported compatibility issues with BP rootstocks and scion cultivars. These rootstocks are, however, highly susceptible to pear decline and fireblight and are difficult to propagate. Susceptibility to pear decline has particularly limited the use of BP rootstocks in Europe.

The BP1 rootstock is being evaluated in the pear rootstock trial site in the Goulburn Valley and has shown reduced vigour and improved yield efficiency when compared with D6 (for both 'Williams' and 'Packhams'. This rootstock is commercially available in Australia but numbers can be limited. Results from the trial can be found by visiting the APFIP website.

Figure 2: 'Williams' on BP1 in its 5th leaf at the APFIP pear rootstock trial site in the Goulburn Valley. Central leader system with plant spacings of 4.5m x 1.4m (1585 trees/ha)

Pyrodwarf

Pyrodwarf originated from a crossing between Old Home and Bonne Luise d’Avranches. It reportedly has a vigour 50% lower than Pyrus Calleryana D6. It has good graft compatibility with European and some East-Asian pear varieties. It has a low susceptibility to iron chlorosis, is tolerant to waterlogging and is winter hardy. Rootstock evaluations in Europe have however shown it to still be too vigorous for intensive systems.

This rootstock has been introduced in Australia and is hoped to be included in future in the APFIP pear rootstock trial. This should yield information about its performance in local conditions.

Pyriam

Pyriam is a clonal rootstock developed by INRA in France through open pollination of ‘Old Home’. It is seen as a potential replacement for BA29 in south-east France. It reportedly has good graft compatibility with ‘Williams’, a good ability to be propagated, low susceptibility to Fireblight and good growth and habit in the nursery. It induces slightly higher vigour than BA29 but has equal productivity and fruit sizes (Simard and Michelesi 2002) . No published data was available to compare its performance to quince.

BM2000

BM2000 originated in Australia as a result of open-pollination of likely parents ‘Williams’ and ‘Packhams’. It is described as having medium vigour compared to Pyrus Calleryana D6. There is no experimental data regarding precocity, productivity and yield efficiency in the literature.

This rootstock is currently in the APFIP pear rootstock evaluation site and has demonstrated reduced vigour and better yield efficiency than D6 (on both 'Williams' and 'Packhams'). Results from the trial can be found by visiting the APFIP website

Figure 3: 'Williams' on BM2000 in its 5th leaf at the APFIP pear rootstock trial site in the Goulburn Valley. Central leader system with plant spacings of 4.5m x 1.4m (1585 trees/ha)

Fox Series

Fox 11 and Fox 16 are two of the fox series which have plant variety rights. Fox 11 vigour similar to BA29 and is recommended for tree densities between 2000-2500 trees/ha. It also has good compatibility and tolerates high alkalinity. Fox 16 has a vigour slightly greater than BA29 and it has drought tolerance but is less tolerant of high alkalinity than Fox 11.

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Availability in Australia

At present the most widely available rootstock for pear production is D6.  It is expected that Quince A, BM2000 and BP1 should be more readily available in the coming years.

The APFIP pear rootstock trial at present is the only source of rootsock performance data under Australian conditions. Results from the trial can be found by visiting the APFIP website 

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Further information

These Australian and international sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

Rootstock characteristics

• Pear rootstocks - New South Wales DPI AgFact (external link).

Rootstock performance in Australia

• Australian Pome Fruit Improvement Program - pear rootstock trial data from the Goulburn Valley (external link).

Accessing rootstocks

Growers should liaise with their nurseries about accessing rootstocks for intensive pear production (external link). 

• Australian Pome Fruit Improvement Program may also provide some guidance on rootstock availability (external link). 

International Resources

Rootstock characteristics

• 'Clonal rootstocks for apples and pears'  - Hortfact (external link).
• Pacific North West pear rootstock trial -  Washington State University site (external link). 

References

Maas, F. (2006). “ Evaluation of Pyrus and Quince rootstocks for high density pear orchards.”  Scientific Works of the Lithuanian Institute of Horticulture and Lithuanian University  of Agriculture 25(3). 13-26

Mielke, E.A., and Smith, L. (2002). “Evaluation of the Horner rootstocks” Acta  horticulturae 596: 325- 330. 

Mielke, E.A., and Sugar, D. (2004). “Initial seven-year evaluation of thirteen Horner pear  rootstocks”. Acta horticulturae 658: 513-517

Johnson D., Evans K., Spencer, J., Webster, T., Adam, S. (2005). “Orchard comparisons of new Quince and Pyrus  rootstock clones.” Acta horticultuae 671: 201-207

Simard M.H., Michelesi J.C. (2002). “'Pyriam': a new pear rootstock.” Acta  horticulturae 596: 351-355.

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The quality of nursery trees is one of the most important factors when establishing an orchard. The profitabilty of any intensive pear orchard is related to its ability to produce early yields of quality fruit. This is highly dependant on trees having good growth and developing an adequate canopy structure in the early years after planting.

An adequate canopy structure is one that allows for optimal light interception and has enough buds with the capacity to produce flowers.  This is best achieved through using high quality nursery trees that already have in place a good canopy structure.

It is also important that nursery trees are healthy - that is free of pest and disease and mechanical injury.

Types of nursery trees

Which tree will give the best result for an intensive system? 

Ordering a nursery tree 

Further information

References

Types of nursery trees

There are a number of different types of nursery tree that can be used when planting an orchards. These include

1. One year old whips - produced through bench grafting of rootstocks in winter, planting in spring and then encouragement of a single bud to grow. These are often unbranched and can lack uniformity.
2. Summer budded trees - produced over two seasons with rootstocks planted in spring and budded in summer. These are headed at the bud in late winter, with the bud growing into a tree the next season.
3. Two year old feathered trees (or 'Knip' trees) - produced over 2 seasons. One year old trees produced through either bench grafting or summer budding are held over in the nursery for another year and in the second winter are headed to the required height (50-75cm). A single shoot is allowed to grow from the top bud and any laterals are removed. The shoot grows very vigorously and produces branches on the current seasons growth (called feathers).
4. Sleeping eye trees - summer budded rootstocks that are cut above the dormant bud and stored for planting in a nursery or orchard.

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Which trees will give the best results for an intensive system?

Many studies from around the world have shown that the use of  highly feathered nursery trees, such as the two year old well feathered (knip) trees  can result in significant yields in the second and third year after planting. This is compared to unbranched trees (or whips) that may take four or five years to produce a yield.   

Highly feathered trees such as the 'knip' trees are the most favoured nursery tree type in many European production systems.  

Generally the best quality 'knip' tree should have   

• A minimum tree height of 1.6m above graft union 
• A minimum stem diameter of 14-16mm measured at least 10cm above graft union
• A number (6-15) of well positioned feathers/laterals with a maximum length of 30cm
• Feathers starting no less than 80cm above the soil.
• Feathers with moderate vigour - that is wtih a  diameter no greater than 30% of the trunk.
• Feathers with wide crotch angles

Figure 1 & 2 : 'Knip' trees in Belgium.

Often these trees require little (or no) pruning at planting, particularly if feathers are already well located around the tree.  

The drawbacks of these trees is that they are produced at a higher cost and therefore will be more expensive than a one year whip.  However the production losses through using cheaper, poor quality trees will cost more money in the long term than the initial cost of using quality trees.  

It is important however that growers understand the requirement of their intended system before deciding on a nursery tree. Often as densities get higher (>4000 trees/ha) and spacings narrower, highly feathered trees become less desirable. Systems such as the super spindle (4000-7000 trees/ha) are often best planted with whips with short branches. These treese should still be of a good quality however (uniform in size and healthy). 

Sleeping eye trees can often be an option to keep tree cost down in very high density orchards. The danger with sleeping eye trees is that the risk of tree loss at planting can be higher. This was demonstrated by Elkins et al. (2008) who found that even though sleeping eye trees were cheaper than 'standard' nursery trees (similar to whips) the cost of replacement and intensive training negated the benefit of the lower purchase price.

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Ordering a nursery tree 

When ordering a nursery tree, growers need to consider what tree will give them the best start for their system. This requires a good understanding of the planting site and intended system. If growers want highly feathered nursery trees, they will need to order atleast 2-3 years in advance from the nursery. If whips are the tree of choice, there is less lead time required, but growers should still order with enough time to ensure best chance of starting a system with the highest quality trees.

Fundamentally,growers must develop a good relationship with their nursery in order to get the right tree for their system. Being able to clearly specify the requirements of a tree can make this a smooth transparent process. APFIP has released a guide to nursery tree specifications, a useful reference when ordering trees from a nursery. 

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Further information

These Australian sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other management recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

Nursery Tree Specification

• APFIP Nursery Tree Specifications - For information on nursery tree specifications (external link).

Planting nursery trees

• Go to the planting nursery tree page for more information on management of nursery trees at planting

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References

Elkins, R.B., DeJong, T.M., Klonksky, K., and DeMoura R. (2008). "Economic evaluation of high density versus standard orchard configurations; Case study using performance data for 'Golden Russet Bosc' pears". Acta Horticulturae 800: 739-746

 Mostly pears are considered self-infertile (can not produce fruit from their own pollen) and require cross pollination.

Insufficient pollination may result in reduced yields and misshapen fruit. It is important when planning an intensive pear orchard to ensure adequate pollination through

• planting compatible varieties that flower at the same time
• careful planning of orchard configuration for effective pollinizer arrangement
• ensuring satisfactory bee populations in the orchard at flowering
• minimising competition from other flowering plants

Varieties for cross-pollination of pears

Planting pollenisers

Ensuring satisfactory bee populations at flowering

Minimise competition from other flowering plants

Further information

References

Varieties for cross-pollination of pears

It is important that pollinating varieties are compatible. The main variety and pollinator must also have a flowering period that coincides enough to ensure pollen is available as flowers open.

The following table lists compatible pollinators for selected pear varieties.

Table 1: Pollination table (adapted from Campbell (2002))

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Planting pollenisers

The placement of pollenisers in the orchard is particularly important in intensive production systems. Pollenisers need to be placed close to the main variety to ensure good pollenation.

Bees tend to fly down rows an not across them so full row systems of pollenisers (often used in old low density systems) may have limited effectiveness in intensive production systems. 

A more effective layout is one that has pollenisers evenly planted throughout every row.

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Ensuring satisfactory bee populations at flowering

Often growers will need to hire honeybee colonies as populations of wild or feral honeybees are low. Bees can be killed as a result of pesticide application in the orchard so growers will need to ensure they plan pesticide application programs to avoid this.

Suggested stocking rates for pears are provided in the resources below. However growers should consult an apiarist and local expertise to determine honeybee requirements for their orchard. 

Bee activity under hail netting

In order to ensure adequate pollination under hail netting, there are a number of factors that need to be managed. These were outlined by Middleton and McWaters (2002) and include

• Placement of hives under the netting  once flowering has commenced as bees will be less likely to fly into blocks covered by hail netting. If bees are introduced too early they will seek alternative nectar and pollen outside netted area 
• Allowing an adequate gap between the top of the trees and hail net cover for optimum bee flight
• Bees may become trapped in the netting when first introduced. These bees will die and be replaced by younger bees that have acclimatised to the conditions.
• Temporary removal of netting (or sections of netting) during flowering to allow bees to fly in and out and reduce numbers of bees trapped.

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Minimise competition from other flowering plants

Pear nectar is often less attractive to bees due to its low nectar content. This means if there are other flowering plants in close vicinity to the orchard, bees may be drawn away from the pears to forage. It is important to control flowering weeds around the orchard to minimise competition.

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Further Information

These Australian and international sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

Bee Pollination

• Bee pollination benefits for pear and nashi - Department of Agriculture Western Australia Bulletin (external link).
• Honeybee pollination of fruit tree crops - Victorian Department of Primary Industries Ag Note (external link).

Varieties for cross pollination

• European pear varieties - NSW Department of Primary Industries AgNote (external link).

References

Campbell, J. (2002). ' European Pear Varieties'. Retrieved January 2009 from http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0013/120217/european-pear-varieties.pdf

Middleton, S. and McWaters, A. (2002). ' Hail Netting of Apple Orchards - Australian Experience'. Compact Fruit Tree 35(2) : 51-55

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Intensive production systems offer the advantage of earlier production than traditional low density systems and better efficiency of harvest and management operations.

These advantages come at a cost however - as intensive systems are more expensive to establish and subsequently have a higher financial risk associated with crop loss or failure.

There are many interlinked decisions that need to be made during initial planning for an intensive system that are critical to ensuring success. These decisions will be influenced by a range of site, economic and management factors. These factors will vary from orchard to orchard.  

Making the right choices about system establishment and management depends on growers having a good understanding of 

•  the financial commitment and risks of an intensive production system
• the management commitment needed to ensure maximum potential for high annual yields beginning as early as possible and
• the importance of integrating the 'technical' aspects (variety x rootstock x planting system x management regime) for the best possible orchard outcome 

Financial Commitment

Management Commitment

Choosing the Right Combination

Risks

Key Planning Questions

Financial Commitment

It is crucial that before moving ahead with an intensive orchard, growers have a good understanding of the financial commitment required and the capacity of the business to meet this commitment. This means having a clear idea of the financial position of the business and the cost of intensive system options.

The cost of establishing an intensive system are higher than for a traditional system. The higher cost can be due to;  

• a requirement for higher tree numbers
• the installation of trellis/support systems
• the requirement for more intensive management during the establishment years 
• the cost of interest on borrowed money to establish systems

Often establishment and annual overhead costs can only be reduced to a certain threshold - and not enough to have a significant influence on profitability. Cost cutting in the establishment phase may also impact on the long term performance of the orchard. 

 The key to making money in a new planting is to have these costs paid off as soon as possible. This means early production of high yields of good quality fruit that the market wants.   

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Management Commitment

Intensive orchards often require far more careful management during the early establishment years to ensure good growth and early fruit production. This means paying careful attention to the quality of the planting materials, ensuring optimal site preparation and  tree planting, tree nutrition, irrigation, pruning and training.

Growers need to consider what management commitment they are able or prepared to make to an intensive system and choose a system that will suit their situation. A whole range of different skills or technologies may need to be adopted in order to ensure maximum potential for early and sustained high annual yields of good quality fruit.

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Choosing the Right Combination

When planning an intensive system, it is critical to choose the right combination of rootstocks, varieties, planting systems and management options. It is also important to understand the inherent site characteristics such as soil fertility and climate and their impact on system choice. Mistakes made during the establishment phase such as spacings too wide for the vigour of the site and rootstock will have long term impacts on production.

The following pages on this site outline key information about these areas. It is important to recognise that each orchard will have its own set of  deciding factors - so there is no easy recipe for success. Planting systems that are technically efficient and productive may not be practical for all orchards.

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Risks

The biggest financial risk with an intensive production system is crop loss or failure - particularly in the early years of establishment. There may be a range of reasons for crop loss or failure including extreme weather or poor management decisions. The failure to produce early yields will not only have an immediate financial impact but may also affect yield production in subsequent years.

It is crucial that orchards have in place risk management options right from the beginning. This is particularly imporrtant for  those risks that growers have much less control over - such as extreme weather events.

Any planning for an intensive orchard should include provisions for managing the risk of crop loss  such as  hail netting, frost fans, overhead irrigation for evaporative cooling or even crop insurance. This may mean that the establishment costs are further increased and a further delay in reaching the break even point on the system. It is important however to assess the likelihood of these events occurring and weigh up the cost of risk management options versus the cost of losing a crop.    

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Key Planning Questions:

1. How much will the system cost to establish? 
2. Do I have access to the funds needed to cover this cost?
3. If I choose to borrow money can I afford the cost of interest? 
4. What impact would crop loss or failure have on the ability of the business to cover costs of establishment?
5. What management tools will I need in place to minimise the risk of crop loss?
6. What management skills and tools are required to ensure the system achieves early and sustained yields to help pay off establishment costs? Can I afford to commit to these?
7. Have I got access to all the required resources for an intensive system (eg. varieties, rootstocks, nursery trees, support materials)?

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Some of the systems that are utilised around the world will be briefly described.

Systems derived from central leader

Double leader systems

Palmette systems

V/Y systems 

Systems derived from central leader

Pear trees are trained as central leader systems to develop a conical or pyramidal shaped tree that can be free standing or supported by a post or wire support systems. These tree shapes are considered one of the most efficient for light interception and crop production.

There are various systems that use the central leader concept. The major differences between these systems include tree density, height, leader management and whether or not permanent scaffod branches are retained.

Spindle

 The spindle system (sometimes referred to as the free spindle or bush spindle) is generally suited to densities up to 2000 trees/ha and have a height of 2-3m. The planting distance is usally 3-5m x 1-2m depending on rootstock vigour. Spindle systems are usually planted using well feathered two year old nursery trees.

At planting, the leader is not headed and a number of laterals are selected to form part of the permanent scaffolds in the bottom of the tree. Competing laterals that develop on the leader are removed early. As the leader grows more scaffolds are selected and spaced equally. 

Leader dominance is important and if lost will result in a reduced tree canopy. If it becomes too strong, lateral growth and development will be reduced.

Spindle systems can be free standing, but mostly ustilise some form of support (2-3 wire trellis).

                                 Figure 1: Spindle system in Belgium, planted at 4.5m x 1.25  (1700 trees/ha). 'Conference' on Quince Adams 

See Gallery for more examples of spindle systems.

Vertical Axis

The vertical axis is similar to the spindle and it is often hard to distinguish the difference, except that the vertical axis does not have permanent scaffolds. This system suits densities between 1000-2500 trees/ha with a spacing of 4-5m x 1-2m . Height can reach up to 3m.

These systems are best planted with well feathered nursery trees. A central leader (axis) is developed with 'weak' (small diameter) fruiting branches arising around the leader.   The leader is not headed back in the first few years of this system to ensure that weak fruiting branches are developed.  These fruiting branches are systematically renewed to prevent them becoming premanent scaffolds .

Support of a multi wire trellis is required for these systems.

                             Figure 2: A Spanish 'Axis' system. 'Conference' on Quince C. Planting distance is 3.75 x 1-1.25m (2100-2600 trees/ha)

See Gallery for more examples of spindle systems.

Slender Spindle

The slender spindle system involves more severe pruning than the vertical axis and is suited to densities of 2000-5000 trees/ha. The planting distance is 3.5m x 1-1.5m and tree height is usually restricted to 2-3m. 

Well feathered nursery trees are preferred for planting the slender spindle system.

Super Spindle

The super spindle system is utilised for super high density orchards on weaker rootstocks such as Quince C. These systems have densities of greater than 4000 trees/ha.

Planting distance is usually <3m x <0.8m and tree height is 2-3m.

The main concept of super spindle orchards is to have closely spaced compact trees with short fruiting wood or spurs evenly spaced along the central leader. These systems require a multi wire support.

Figure 3: Super spindle orchard in the Netherlands. 'Conference' on Quince C and spaced at 4m x 03m. This orchard is in its fourth leaf and was producing 45-50 tonnes/ha. In its second leaf it had produced 35 tonnes/ha.

See Gallery for more examples of super spindle systems.

Double leader systems

Double leader systems are trained with the aim of achieving high leader densities whilst keeping tree numbers (and cost) down. Trees are usually planted at approximately 3-4m x 1-1.2m equalling a tree density of around 3000 trees/ha. However, the development of double leaders mean that the leader density is 6000 trees/ha.

One such double leader system is the Bibaum^® system. This system was developed in italy and involves planting specially developed nursery trees that have 2 leaders (or axes). Trees are split at 25cm above the ground into two eaqually strong leaders (Musacchi 2008). This system is usually planted at 3.3m x 1-1.25m in a single row. Leaders are trained parallel to the row and are spaced at 50-60cm apart. Relatively weak fruiting branches are developed on each leader.

Figure 4: 'Williams' on Quince Sydo (with a 'Buerre Hardy' interstem) in a Bibaum^® system in Italy. Plant spacing is 3.3m x 1.0m (3000 trees/ha)

See Gallery for more examples of double leader systems.

Palmette systems

The palmette system and its variations are generally limited to wide within row spaciings (>2.0-2.5m) and by a taller tree giving a medium planting density of 700-1500 trees/ha. There are a number of different kinds of palmette training but all generally comprise of a central leader with scaffolds in the plane of the row only.

Tiers of scaffolds are chosen as the leader grows each season and are tied to wires to reduce vigour and promote spurring.

The palmette is considered a traditional system, however it is still used widely in areas where the environment, species or the cultivar/rootstock combinations are conducive to vigorous growth (Corelli-Grappadelli 2000).

                                               Figure 5: 'Comice' on Quince BA29 in a palmette system in Spain. Plant spacing is 4m x 1.75m. 

See Gallery for more examples of palmette systems.

V Systems

There are various V or Y shaped orchard systems used in pear production.

Y shaped systems have trees with a vertical trunk and two opposing arms of the tree trained to either side of the trellis and are in single rows. V shaped systems have alternating trees leaned to one side of the trellis and can be double or single rows.

Two of the main systems used for pear production are the V Hedge and Open Tatura Trellis.

V Hedge

The V hedge system is widely used inthe Netherlands and Belgium and is a variation of a Y shaped system. It is a single row system with a planting distance is 3.5m x 1.25m equalling approximately 2000 trees/ha (Deckers and Schoofs 2004). These systems are planted using well feathered two year old nursery trees. Four feathers are kept as fruiting branches and considered as four central leaders on one stem. Tree height is maintained at 2m with an opening of the V of 1.4m. Often each 'leader' is supported by bamboo stakes.

                                              Figure 6: Young V Hedge orchard Belgium. 'Conference' on Quince Adams planted at 3.5m x 1m.

See Gallery for more examples of v hedge systems.

Open Tatura Trellis

The Open Tatura trellis  is a modification of the original Tatura Trellis developed in Australia. The Open Tatura Trellis consists of two rows of trees (separated by approximately 0.5m) that are  planted alternately in a V trellis. It is generally planted 4-4.5m x 0.5-1m to give a density of about 2000-5000 trees/ha. Trees can be trained in a number of different ways in this system. The most common are the

• Open Tatura with double leaders which involves training each tree with two leaders (approximately 1m apart).
• The Open Tatura with single leader which is similar to planting a  slender spindle system.  
• The Open Tatura with cordon which allows for a moderatly dense orchard of around 2000 trees/ha with approximately 8000 fruiting units growing up the wires (Van Den Ende 2005). Nursery trees (usually whips) are bent over at planting and trained to the horizontal. Fruiting units are encouraged at regular intervals along the trunk and can be renewed regularly.

               Figure 7: 'Williams' on Pyrus Calleryana D6 (D6) in Open Tatura. Trees are trained as single leaders and spaced at 4m x 0.50m (4444 trees/ha).

The performance of 'Williams' on D6 rootstock in an Open Tatura Trellis system was investigated in a trial in the Goulburn Valley, Victoria. Results of this trial can be downloaded here.

See Gallery for more examples of Open Tatura Trellis systems.

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Further Information

These sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linked from this page you are leaving the intensivepear.com website

International Resources

Intensive Pear Orchard System Development

• The Pear Production and Handling Manual has been produced by the University of California. It provides detailed information about various pear production systems with specific detail on the training and pruning requirements for each. You can purchase this book directly through this website (external link).  

References

Corelli-Grappadelli L. (2000). “The Palmette Training System.” Acta Horticulturae 513 : 329- 336.  

Deckers T., Schoofs, H. (2004). “Management of high density pear orchard.” Compact Fruit Tree 34 : 2001-2120. 

Elkins, R.B., DeJong, T.M., Klonksky, K., and DeMoura R. (2008). "Economic evaluation of high density versus standard orcahrd configurations; Case study using performance data for 'Golden Russet Bosc' pears". Acta Horticulturae 800: 739-746

Musacchi, S. (2008). “Bibaum®: A new training system for pear orchards.” Acta  Horticulturae  800: 763-768

Van Den Ende, B. (2005) "Open Tatura with cordon: A new way to grow fruit." Good Fruit Grower 56 (8): Retrieved from http://www.goodfruit.com/issues May 2007. 

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Tree growth during establishment years is critically important to the success of an intensive orchard. Any factor that inhibits growth will wind up costing growers through tree replacement and often delayed bearing. 

Properly preparing the planting site for an intensive pear orchard is integral to achieving maximum growth and productivity in the first few years of establishment.

Planning Early

Evaluate the Site

Replanting Existing Sites

Site and Soil Preparation

Further information

Planning Early

Planning site development should be done well before replanting, particularly if the site is an old/existing orchard block. Growers should be planning developments at least 2-3 years in advance to allow for enought time to

• prepare an accurate budget 
• order trees
• order trellising and irrigation systems
• plan labour, cultural practices and equipment requirements
• identify and correct any drainage or nutrition problems and,
• determine if fumigation is required

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Evaluate the site

Before the final decision is made to develop a site, it should be thoroughly evaluated. An evaluation should take into account the site suitability for pears. It is particularly important to understand

• drainage
• soil type
• slope
• prevailling winds
• aspect
• frost susceptibility

This may require mapping of the area to identify issues and plan for corrective measures. If it is a replant site it is particularly important to analyse the past history of the orchard and identify potential problem areas.

Soil Test

It is imperative to obtain a soil test before preparing the site. This will identify whether you need to apply nutrients or improve soil.  

pH, nutrients, salinity and organic matter

Soils should be tested for pH, soil nutrients, salinity and organic matter so that any ammendments can be made before planting. If surface runoff during irrigation indicates slow soil infiltration rates a test for gypsum requirement may also be needed.

A subsoil sample to check pH and gypsum requirement is useful if the site has been replanted more than once.  

Risk of replant disease when replanting old blocks

Replant Disease is one such factor that can cause poor growth and sometimes death in newly planted orchards. Replant disease can be specific or non-specific. Specific replant diseases  such as Specific Apple Replant Disease (SARD) affects apples planted directly after apples. Non-Specific replant disease can affect apples planted after other fruit crop species (eg. stonefruit) or other fruit crop species planted after each other (eg. cherries after apples).  

The exact causes of replant disease are still yet to be identified but it is widely attributed to a combination of soil borne organisms such as parastic nematodes,  and soil borne fungi and bacteria.

Recognising replant disease is often not easy initially, a range of factors need to be considered. Above ground the main symptom is a general lack of tree vigour and a failure to thrive. Below ground the roots can be blackened, very few root hairs and a tendency for premature decay of the roots. Replant disease is generally non-lethal but tree deaths can occur in newly planted trees, often another pathogen is also associated with the tree death. Affected trees tend to recover and make normal growth after 2-3 years however the economic impact of the delayed production and low early year yields can be very serious. It can turn a potentially profitable orchard into a poor or negative investment.

Pears are generally regarded as being less susceptible to replant disease than species such as apples. However, precaution should still be taken when planting pears on more dwarfing rootstocks such as quince into existing fruit blocks - and particularly old pear blocks.

Bioassay tests of soils can give an indication of the affect the soil will influence the growth of young trees and whether or not soil fumigation or other ammendments are needed.

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Replanting existing sites

Trees should be removed immediately after harvest - if conditions enable easy removal of trees an roots. Timing and method of removal will depend on the site conditions, costs and availability of equipment.  

                                                                                     Figure 1: 'Williams' pears removed for redevolpment

Remove as many roots as possible

Old roots can harbour harmful levels of soil organisms that can reduce the performance of newly planted trees. Decaying roots can be toxic to young trees and can be a source of nematodes and disease. It is important to remove trees when soil conditions are suitable for maximum removal of roots.

After tree removal tree lines should be ripped to 35-40cm to remove any remaining roots. If practical all root pieces longer than 30-40cm and larger than 4-5cm in diameter should be removed.

Do not burn old trees on land to be replanted

Heat generated by burning old trees can adversely affect soil micro-organisms and nutrient availability under the heap. For orchard uniformity it is best to burn the trees off the replant site. If trees must be burnt on site, several small heaps are better than one large one.

Avoid erosion problems on steep slopes

On steep slopes tree removal can cause soil erosions. Growers may need to look at measures to minimise the speed of water running down the block. A cover crop should be planted if land is going to be left fallow for a long period.  

Site and Soil Preparation 

This is the critical aspect of redeveloping an orchard. The greater the attention to detail in this phase the greater the long-term benefits.  

Weed control

Managing weeds before the planting of a pear block will help reduce the competitive pressure of weeds during young tree establishment. It is particularly important to control perennial weeds before planting as these are harder to manage in established blocks than in open ground. They will also compete with any cover crops or permanent sod sown. For information on weed control please visit the weed management page.

Ripping  

Ripping can improve soil aeration and drainage, reduce compaction problems and remove roots from previous orchard plantings (if needed). Ripping is best done when soil is dry.

Cultivate soil

Planting sites need to be well cultivated with friable soil. Cultivation can also unearth old roots in an existing orchard block.

Mark out new rows

It is important to minimise the number of new rows in old row positions.   

Considerable debate centres around which is the best row orientation. As a general guide all orchards should be planted with as close to a north-south row orientation as practical except where site constraints or operator safety prevent this occurring.

Fumigate if required

Fumigation is only one tool that can be used to prepare the site, often many of the cultural practices such as adjusting nutrition and soil structure can reduce the need to fumigate. 

If fumigation is required prepare the soil to the right tilth and ensure that there is adequate soil moisture (dry soils minimise the effectiveness of fumigation). Depending on the chemical used to fumigate soil covers may be needed. These covers can greatly increase erosion problems on steeper sites so install appropriate erosion minimisation actions, ie interceptor drains etc

Fumigation is most successful in warm moist soils with temperatures over 16°C – Autumn is preferred to spring as the chemical must be removed before planting can proceed.  Germinating quick sprouting vegetable seeds can be used as one test to check wether the chemical has been properly removed from the soil.

Even out the site if required

Some minor site earthworks may be needed to fill in low spots etc. If major earthworks are required this should be done prior to fumigation.  

Apply and incorporate fertilisers and soil ammendments

Prior to final soil preparation any fertilisers or soil ammendments such as gypsum or lime should be broadcast and incorporated at the recommended rates (determined by soil tests) to a depth of 15-20cm.

Mound treelines if necessary  

 Mounding of tree lines can improve drainage as well as increase the depth of topsoil available to trees. This is particularly important where there is an impermeable clay sub-soil. Mounding can be done through moving topsoil from the centre of the traaffic line to the treeline. Mounds should be about 0.5m high.

Final soil cultivation

The final soil cultivation should only be done when all fertiliser, soil amendments, mounds and grassed waterways (surface drainage) are in place. It should preferably be done on the day of planting. 

Establishment of cover crop or sod culture

 Cover crops or sod culture can help to stabilise the soil and provide a firm surface during planting. They also can reduce weed competition and provide organic matter to the soil. The choice of cover crop may depend on local conditions. Often ryegrass or a mix of ryegrass and clover are used. Before planting the tree line will need to be sprayed to ensure the cover crop doesn't compete with newly established trees.

Installation of support systems and irrigation

It is important that support systems and and irrigation are installed before planting or as early as possible after planting.

Movement of young tree tops can damage tree roots so it is important that they can be secured to a support system. It is also important to minimise any water stress to rapidly growing young trees through irrigation.   

Acknowledgements to Paul James (Rural Solutions SA)  for providing much of this information

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Further Information

Growers should always seek local advice when planning to develop an orchard site. There may be locally specific issues that need to be considered in terms of climate, soil type and nutritional status. 

These resources may be useful for growers. However they are intended as an information source only. Any specific chemical or other management recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

• Successfully Replanting Orchards, Five Easy Steps, A Best Practice Guide by Paul James. This book is available by contacting the Apple and Pear Growers Association of South Australia ( This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ) 

International Resources

• Planting and care of young orchards - Washinton State University Publication (external link).

Grow the tree then crop it – avoid the temptation to overcrop early, as nothing will stop the growth of a dwarfing rootstock quicker than over cropping.

Be prepared to hand thin or remove flower clusters in the first season. For most training systems it is highly advisable to remove any potential crop in the first season as the crop can significantly affect canopy development and subsequent cropping potential.

Minimal tree pruning in the early years is optimal.

Bending of branches to avoid narrow crotch angles.

Promote rapid tree formation and cropping - limit pruning at/ after planting.

In order to obtain excellent growth in the first few years of the orchard, nursery trees need to have optimal management - starting at planting. Even trees of the highest quality can peform badly if not managed adequately.  

It is important that nursery trees receive the very best of care once they reach the orchard.

Key steps when planting nursery trees

Further information

References

Key steps when planting nursery trees

1. Planting site prepared in advance

Site preparation and irrigation and trellis installation should occur well before planting. It is essential that plants have irrigation available immediately after planting. Wind can cause issues with newly planted trees - moving them and breaking roots. Having a support system already in place will minimise this risk.

Figure 1: Pear nursery trees being planted.

2. Tree roots must not be allowed to dry out.

Root activity and growth is important for early establishment and growth of trees. Roots should be kept moist prior to and at planting. Planting a nursery tree when the roots are dry or partially dry will result in root damage and will inhibit tree growth or ultimately tree death. This can be a long lasting effect. 

Ideally trees should be placed in a heeling-in trench upon delivery from a nursery. A heeling in trench should be in a protected location, with good drainage. Trees should be placed in the trench and have roots covered with loose soil. Roots should be watered before being covered.

If it is not practical to do this trees can be placed in coolstorage. This should not be where fruit is stored and trees must be fully dormant.  Trees should be stood upright with roots covered by sawdust. Tops will need to be kept moist.

3. Tree roots should be kept below 70C

New root growth occurs when temperatures reach >7^oC. This draws on the trees reserves as well as increases the risk of root damage when planting (Brown 2008). Some root growth will occur between 2-7^oC. It is important that trees are planted either when dormant (in Winter) or as early in the spring as possible. If planting has to be delayed trees can be stored in a cool room with adequate moisture.

4. Plant trees as early as possible

Early planting reduces the tree stress and allows roots to settle and recommence growth before shoot growth. Ideally trees should be planted between June and mid-August.

5. Plant trees with bud union at least 100mm out of the ground

Trees need to be planted with the bud union out of the ground to avoid scion-rooting. Scion-rooting occurs when the variety grafted onto the rootstocks starts to develop its own roots. This will happen where the bud union is in contact with the ground. Trees should be planted with graft unions at a consistent height above the soil - ideally 100mm.

6. Irrigate as soon as possible after planting

It is important that trees do not suffer water stress. This is often one of the most common problems when establishing new blocks. Ideally trees should be watered immediately after planting and receive regular short intervals thereafter. While the root system is still very small, it may depelete the moisture immediately surrounding each root, and even though the moisture is found a the surface close to the tree, the soil around the roots may be dry (Westwood 1993). They do not require large volumes of water, but enough to create a humid environment around the roots.

7. Adequate nutrition after planting

Often it is not recommended to place fertiliser in holes at planting (as it may harm roots). However, trees should receive adequate nutrition either through fertigation or soil application to ensure good growth. The amount and frequency will depend on the soil conditions at the site.

8. Control weeds

Weed growth can compete with a young tree for soil moisture, nutrients and sunlight. In the first season after planting it is important that weeds are controlled to ensure the young tree can achieve maximum growth. It can be risky to use chemical weed control in the first season and tillage or mulches may be useful.

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Further information

These Australian and international sites may be useful for growers. However they are intended as an information source only. Any specific chemical or management recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice.

Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website.

Australian Resources

Management of young trees

• For more information on the management of young trees, please go to the orchard management section of this site.   

Orchard planting

• Successfully Replanting Orchards, Five Easy Steps, A Best Practice Guide by Paul James. This book is available by contacting the Apple and Pear Growers Association of South Australia ( This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ) 

International Resources

Orchard planting

• Planting and care of young orchards - Washinton State University Publication (external link).

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References

Westwood, M.N. (1993). Temperate Zone Pomology: Physiology and Culture. Timber Press. Portland

Brown, G. (2008). "Successful orchard planting techniques." Australian Fruitgrower 2 (5): 10-12  

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