Editorial:
Standard text:
Working group “Technical Standards in Treework – TeST”
Team of authors:
Jaroslav Kolařík (team coordinator, Czech Republic)
Junko Oikawa-Radscheit (Germany, European Arboricultural Council)
Dirk Dujesiefken (Germany)
Thomas Amtage (Germany)
Tom Joye (Belgium)
Kamil Witkoś-Gnach (Poland)
Beata Pachnowska (Poland)
Paolo Pietrobon (Italy)
Henk van Scherpenzeel (Netherlands)
Gerard Passola (Spain)
Daiga Strēle (Republic of Latvia)
Algis Davenis (Lithuania)
Tomáš Fraňo (Slovak Republic)
Goran Huljenić (Croatia)
Text revision:
Simon Richmond (United Kingdom)
Keith Sacre (United Kingdom)
Sarah Bryce (United Kingdom)
© Working group “Technical Standards in Treework – TeST”, August 2022 (1st edition)
Pictures:
Olga Klubova (Republic of Latvia)
Recommended reference:
European Tree Planting Standard (2022). EAS 03:2022. European Arboricultural Standards
(EAS), Working group “Technical Standards in Tree Work (TeST)”.
EAS 03:2022 (EN) – European Tree Planting Standard.
Table of Contents:
- Purpose and content of the standard
1.0 Purpose
1.1 Main objectives
1.2 Biosecurity - Normative references
2.1 Qualification
2.2 General safety requirements - Location of tree planting
3.1 Regions
3.2 Site inspection
3.3 Tree species selection
3.4 Preconditions of the planting site
3.5 Potential underground space
3.6 Types of soil
3.7 Open growing place
3.8 Degraded soil conditions
3.9 Planting spots in hard surfaces - Tree stock quality
4.1 Introduction
4.2 General features
4.3 Desired image of adult tree
4.4 Additional quality requirements for open-grown trees
4.5 Additional quality requirements for park trees
4.6 Additional quality requirements for avenue trees
4.7 Procedure for tree hand-over - Standard planting procedure
5.1 Introduction
5.2 Time of planting
5.3 Transport
5.4 Root management
5.5 Site and soil amendment
5.6 Planting pit
5.7 Tree placement / planting
5.8 Anchorage systems
5.9 Stem and crown protection
5.10 Mulching
5.11 Water supply systems
5.12 Tree pruning at planting - Additional technical solutions
6.0 Introduction
6.1 Compaction for infrastructure
6.2 Structural soils
6.3 Pressure distributing systems
6.4 Soil cells and tree bunkers
6.5 Root bridges
6.6 Root pathways
6.7 Sustainable urban drainage systems (SUDS)
6.8 Aeration systems
6.9 Grilles
6.10 Modifications of the immediate surroundings of the trees
6.11 Root barriers
6.12 Car protection
6.13 Planting in waterlogged soils - Post-planting tree care
7.0 Introduction
7.1 Inspection and removal of anchoring and protective elements
7.2 Tree pruning
7.3 Water supply
7.4 Weeding
7.5 Protection against pests and diseases
7.6 Mulch replenishment - Palm tree planting
8.1 Palm tree specifics
8.2 Palm planting procedure
APPENDICES
9.1 Appendix 1 List of trees and tree-formed shrubs with an optimum on alkaline soils
(above pH 7)
9.2 Appendix 2 – List of trees and tree-formed shrubs tolerant to acidic soils (below pH 4)
9.3 Appendix 3 – List of tree species sensitive to salinity
9.4 Appendix 4 – List of invasive tree species
9.5 Appendix 5 – Limits for growth conditions of trees
9.6 Appendix 6 – List of tree species (examples) according to expected crown size in maturity
9.7 Appendix 7 – Relationship of Proctor density to bulk density of soils
9.8 Appendix 8 – Indicative list of tree species according to the strategy model
REFERENCES
1.0 Purpose
1.0.1 This standard was published by the working group of the TeST project (Technical Standards in Tree Work) in cooperation with the EAC (European Arboricultural Council) and was released in August 2022.
1.0.2 In the text of the standard the following formulations are used:
- where the standard says „can“, this refers to possible options,
- where the standard says „should“, this refers to a recommendation,
- where the standard says „must“, this refers to mandatory activities.
1.0.3 The purpose of the standard is to present the common techniques, procedures and requirements related to planting trees in non-forest environments.
1.0.4 The standard sets out safety criteria for arborists and other workers engaged in arboricultural operations. It serves as a reference for safety requirements for those engaged in tree-planting procedures.
1.0.5 Each person must be responsible for their own safety on the job site and must comply with the appropriate federal or state professional safety and health standards and all rules and regulations that are applicable to their own actions. Each person must also read and follow the manufacturer’s instructions for the tools, equipment and machinery that he/she uses.
1.1 Main objectives
1.1.1 Planting amenity trees is one of the most important arboricultural activities and it should be carried out in a way that ensures the establishment and successful development of young trees.
1.1.2 The standard is intended for application in the planting of trees whose main purpose is not the production of fruits, wood and other commodities.
1.1.3 The standard presents common fundamental practices used in European countries.
1.1.4 Other different practices and preferences, based on national and regional experiences, are listed in the national appendices.
1.2 Biosecurity
1.2.1 People who are professionally involved in working on trees are inherently at high risk of transmitting pests and diseases between trees and worksites and thus should apply appropriate biosecurity procedures to limit this risk.
1.2.2 To reduce the risk of transmitting pests and diseases, the cleaning of tools and other equipment should be part of daily maintenance. All equipment should be cleaned and disinfected after use on each site.
1.2.3 Where there is a high probability of trees being infected with contagious pests and diseases, increased biosecurity standards must be implemented. National legislation applies.
1.2.4 Nursery trees should be provided with a tree passport stating:
- the tree species
- a code tracing the producer
- the country of origin of the tree (European, national/regional legislation applies).
1.2.5 Every tree should come from the nursery with a label stating its full scientific name and size class.
1.2.6 Phytosanitary passports for nursery trees must contain certain prescribed elements when the trees are moved within the EU.
One of these elements is called the „traceability code“. (EU Commission Implementing Regulation (EU) 2020/1770)
1.2.7 All trees for planting, including auxiliary material, must be free of diseases and pests, especially species monitored within the EU. (Regulation (EU) 2016/2031 of the European Parliament of the Council of 26 October 2016 on protective measures against pests of plants, amending Regulations (EU) No 228/2013, (EU) No 652/2014 and (EU) No 1143/2014 of the European Parliament and of the Council and repealing Council Directives 69/464/EEC, 74/647/EEC, 93/85/EEC, 98/57/EC, 2000/29/EC, 2006/91/EC and 2007/33/EC
1.2.8 Natural/organic products should be used in preference to plastics.
1.2.9 Avoid transporting soil and plant material (woodchip) over large distances; preferably, use local material.
1.2.10 Planting of host tree species in areas where significant pests and diseases are present should be considered carefully. (Regulation (EU) 2016/2031 of the European Parliament of the Council of 26 October 2016 on protective measures against pests of plants, amending Regulations (EU) No 228/2013, (EU) No 652/2014 and (EU) No 1143/2014 of the European Parliament and of the Council and repealing Council Directives 69/464/EEC, 74/647/EEC, 93/85/EEC, 98/57/EC, 2000/29/EC, 2006/91/EC and 2007/33/EC). The State Phytosanitary Administration provides an up-to-date list of quarantine pathogenic organisms and their host plants.
1.2.11 New plantings should preferably improve species diversity on the site to improve resistance to the spread of potential pests and diseases.
2.0 This standard is complementary to other EU standards and national/regional regulations.
2.1 Qualification
2.1.1 Planting of trees and related arboricultural operations are professional activities that can only be performed by a suitably trained and experienced worker or by a trainee under supervision.
2.1.2 Planting of trees is covered by variety of formal educational programmes in the disciplines of forestry, horticulture, arboriculture and gardening.
2.1.3 Generally accepted proof of an arborist’s qualifications is established by international or national certifications. Within the EU, the following certification schemes are recognised for practising arborists:
- European Tree Worker (EAC),
- ISA Certified Arborist.
2.1.4 The following certification schemes are recognised for consulting arborists:
- European Tree Technician (EAC),
- ISA Board Certified Master Arborist.
2.1.5 Meeting the standards of professional qualification includes continuous professional development/lifelong learning.
National qualification may be recognised locally. These are listed in the national appendices to this standard.
2.2 General safety requirements
2.2.1 Tools and equipment must conform to the requirements of CE and EN standards and certification.
2.2.2 A site-specific risk assessment (SSRA) must be carried out and all relevant control measures, plus a briefing for the work, must be communicated to all workers by the qualified arborist/supervisor on site.
2.2.3 Traffic and pedestrian control around the worksite must be established prior to the start of any arboricultural operations.
2.2.4 Arborists and other personnel working near traffic and operating temporary traffic control zones must be trained in temporary traffic control techniques, device usage and placement, and safe procedures for working near traffic.
2.2.5 Arborists and other workers exposed to risk of highway traffic must wear high-visibility safety clothing which meets the requirements of national regulations.
2.2.6 Arborists and other workers who use any equipment, tools or machinery must be familiar with safe work practices and the use of appropriate personal protective equipment (PPE) in line with the manufacturers‘ instructions for the tools, machinery and equipment in use.
3.1 Regions
3.1.1 In each country, there are different regional systems for defining growing areas, based on experience of tree planting (mainly in forestry) and crop production.
As a rule, in addition to climatic factors, these systems also consider pedological and geological contexts.
3.1.2 See the national appendices for the region(s) definition.
3.2 Site inspection
3.2.1 Initial desktop research should be part of a planting plan, including details of future urban development plans, the location of underground and above-ground infrastructure and its protective zones, and other legislative restrictions (e.g. heritage, nature protection).
3.2.2 A field survey should identify parameters:
- using visual characteristics
- using approximate indication techniques
- using field instruments.
3.2.3 A field assessment of growing conditions must be performed prior to planting. This can include:
- above-ground space
- visual inspection of general soil properties
- level of soil compaction (soil probe or penetrometer)
- water infiltration test.
Laboratory analysis may be appropriate for analysis of soils.
3.2.4 When appropriate, also assess the hydrology of the planting location and its potential impact on the tree, e.g. in places with high groundwater levels. This can be done either by assessing soil horizons (e.g. gley) or by visually assessing the surroundings (e.g. proximity of watercourses, signs of waterlogging, etc.).
3.2.5 The speed of water infiltration into the soil and movement of water through the soil are assessed using infiltration tests within the planting pit. (This type of hydrodynamic test is based on the rapid infusion of a certain volume of water into the planting pit. The rate of decrease of the water level in the well is then proportional to the permeability of the investigated horizon. Proper evaluation of this hydrodynamic test requires measuring the water level in the probe at regular intervals.)
3.2.6 Compaction of urban soils for construction purposes requires levels of compaction up to 95% Proctor density. (The Proctor compaction test is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density. Tests generally consist of compacting soil at known moisture content into a cylindrical mould with a collar of standard dimensions of height and diameter using a compactive force of controlled magnitude. The graphical relationship of the dry density to moisture content is then plotted to establish the compaction curve. The maximum dry density is finally obtained from the peak point of the compaction curve and its corresponding moisture content, also known as the optimal moisture content. For a 100% Proctor test, density varies depending of soil typology. In clay soils Proctor 100% give densities of 1.7 g/cm3; for loam soils 1.8 g/cm3; and for sandy soil about 2.2 g/cm3.) These levels of compaction inhibit root colonisation. The maximum compaction which will still allow root growth is around 85%. Planting trees in higher compaction levels is not advisable.
3.2.7 Soils which are compacted above 85% Proctor density, or 3 MPa measured with the penetrometer, will need decompaction to allow for root growth.
3.2.8 Soils that need to be compacted above 85% Proctor density for infrastructure building purposes and which are also required to accommodate root growth will need auxiliary technical solutions to facilitate this (e.g. replacement by structural soil).
3.3 Tree species selection
3.3.1 The basic procedure for tree species selection for a specific site is to carry out a site survey and an assessment of growing conditions. This must consider the site’s altitude as well as other conditions – e.g. solar and wind exposure, soil, landscape topography, etc.
3.3.2 To maintain natural genetic variability, it is advisable to use local (regional) sources of planting material, particularly for rare species.
3.3.3 Resistance to frost/drought/heat is an important limiting factor for tree selection. The resistance of tree species and adaptation of trees to a specific site should be considered.
3.3.4 In a natural landscape it is advisable to use species that correspond to the natural plant composition in the region (including rare species), as well as tree species traditionally used in the area.
3.3.5 When planting in urbanised areas, the principal issue to consider is the taxon’s ability to survive on the site while optimally performing the required functions. As a result, introduced species and cultivars are frequently used. Use of taxa with the potential to be invasive is restricted. (Regulation (EU) No 1143/2014 of the European Parliament and of the Council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species) (See Appendix 4.)
3.3.6 When trees are planted along roads, the impact of winter road maintenance should be taken into account. It might be appropriate to select salt-tolerant species. Tree species sensitive to salinity are listed in Appendix 3.
3.4 Preconditions of the planting site
3.4.1 Before a planting site is selected, a survey must be carried out to locate utility networks (underground cables, overhead power lines, pipelines, etc.) in the area. Protective zones for utility networks are specified in national/ regional regulations.
3.4.2 Trees along roads (“linear forest”) are essential to achieve aesthetic, biological and microclimatic benefits as well as an adequate environment for drivers (low sun protection, speed limitation, etc.).
3.4.3 Space for above-ground tree parts. The planting site must allow the crown to develop to the dimensions of a mature individual of the given species. Exceptions may include where trees are planted that will be shaped in the future, or for temporary plantings. Surrounding buildings, street infrastructure, above-ground utility networks, surrounding trees, etc. must be taken into consideration.
3.4.4 As a principle, it is not advisable to plant new trees under the crowns of existing ones.
3.4.5 The distance between planted trees (pitch) should correspond to the target dimensions of the crown of the mature tree of the given species (in general 50–100% of the crown spread of a mature tree). Where trees are deliberately planted at a denser pitch (e.g. when establishing tree stands), the technical report must set out the necessary follow-up procedures (pruning or thinning) and include a time-frame for these interventions.
3.4.6 Special requirements resulting from the condition of the planting site and the services required of the tree will influence the choice of species (cultivar) and must be respected (specific clearance, maximum tree height, etc.).
3.5 Potential underground space
3.5.1 Any planting site must have enough under-ground growing space (rootable volume) for new roots to develop so that the tree can grow sustainably.
3.5.2 Rootable volume comprises all soil and substrates that can accommodate root growth (that is, enough oxygen, moisture and mine- ral supply with a healthy soil food web).
3.5.3 The size of the rootable volume will differ according to the spatial requirements of different tree species (see Appendix 5).
3.5.4 The rootable volume is quoted in m3. The usable depth of the rootable volume of trees is at least 0.5 m and usually no more than 1.5 m. For new urban designs, it is advisable to avoid conflicts between tree roots and infrastructure by respecting a minimum obstacle-free distance between the tree and the infrastructure. This distance depends on the specific situation, tree size and the type of infrastructure but is typically between 0.5 m and 3 m.
3.5.6 On existing tree sites these distances can often not be respected when (re)planting trees, so mitigating or repetitive remedial measures (see chapter 6 – Additional technical solutions) might be necessary to minimise future conflicts.
3.5.7 Planting trees within the protective zones of utility infrastructure may require the agreement of the utility manager and the use of auxiliary technical solutions to reduce conflicts.
3.5.8 Installation of new utility infrastructure within the root protection zones of trees is not advisable. Where necessary, all means must be taken to protect rootable volume and the root systems of existing trees (e.g. trenchless technologies).
3.6. Types of soil
3.6.1 In general, we distinguish 4 specific types of soil:
- clay
- loam (silt)
- sand
- peat.
3.6.2 Clay soils have low drainage and low aera- tion, but good mineral and water retention capacity. These soils can easily be overcompacted. The planting pit should drain sufficiently so that waterlogging is prevented.
3.6.3 Sandy soils have good drainage and aeration, but low mineral and water retention capacity. These soils dry out quickly and, in general, even if compacted retain sufficient porosity.
3.6.4 The capacity for water storage and water delivery in sandy soils depends on the percentage of organic matter (stable humus) and/or percentage of clay/loam particles.
3.6.5 Planting trees in peat soils is not common in urban situations. Trees planted in peat are growing on unstable soils and have a shorter life expectancy. Smaller-sized trees should be preferred.
3.6.6 The depth of the peat layer and the pH level must be measured before planting to select the most suitable tree species for the site.
3.7 Open growing locations
3.7.1 Trees planted in normal soil that is not degraded usually do not need special measures.
3.7.2 Minimal soil amendments can be provided to optimise tree resilience, e.g. improving root space, oxygen supply, moisture retention, mineral supply and the soil food web.
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To be continued.
