The word quality is often used by those purchasing young trees from the nursery. The word is ill defined and can be ambiguous. Knowledge of nursery production systems, the reasons for and the outcomes of production processes are often poorly understood. This lack of knowledge results in specification documents produced to procure young trees often being poorly constructed and inadequate.
The purpose of this specification manual is to explain the nursery production processes involved in the production of young trees. It is intended to highlight the good practice and the bad practice found in the three principle production methods used on UK tree nurseries and provide clear. It will also provide clear, concise statements which can be used in the drafting of specifications for the procurement and supply of young trees. (These statements appear below in red italics to enable clear recognition)
The specification manual will feature clear diagrams which can be used to inform and clarify young tree specifications. It offers a Barcham Trees perspective of what is important when constructing young tree specifications and what our nursery aspires to but it is recommended that BS 8545 Trees: From Nursery to Independence in the Landscape (2014), The European Technical and Quality Standards for Nursery Stock (2010) and the National Plant Specification Guide www.gohelios.co.uk are also referred to.
For the purpose of this manual, young trees are those produced on a single stem beginning with a stem circumference (girth) of 6-8cm at 1 metre high. All nursery trees produced in Europe are graded by the stem circumference at 1 metre above ground. This is illustrated in the diagram and table below.
It is important to note that even the most detailed and comprehensive of young tree procurement specifications cannot compensate for inappropriate species selection.Keith Sacre MSc Arb, BSC (Hons) Arb, MICFor, Chartered Arboriculturist
Height and Clear Stem of Nursery Trees.
|Size of tree||Circumference at 1 metre||Height of tree||Clear stem|
|Standard||8-10cm||2.5-3.0 metres||1.75-2.0 metres|
|Selected Standard||10-12cm||3.0-3.5 metres||1.75-2.0 metres|
|Heavy Standard||12-14cm||≥ 3.5 metres||1.75-2.0 metres|
|Extra Heavy Standard||14-16cm||≥ 3.5 metres||1.75-2.0 metres|
|BS 8545 and BS 3936|
copyright © 2015 Keith Sacre. All rights reserved