Measure, mark and assess the volume of standing trees

This standard covers the measuring and assessment of the volume of standing trees in preparation for harvesting and extraction. It also includes the selection and marking of sample plots and marking trees ready for extraction.

The marking of trees can be to indicate removal or those that are to remain in the longer term. Selection and marking of trees must include taking into consideration extraction routes.

You will need to take account of any restrictions affecting the work e.g. designated sites, presence of listed structures, wildlife, non-native invasive or protected species etc.

You are required to avoid or minimise damage or disturbance to the surrounding area including trees, other vegetation, wildlife and habitats, or to any structures, fences, paths, signs, ditches/waterways or drains, and to ensure that other site users are not put at risk by your work.

Your work must conform to all relevant legislation and codes of practice, industry standards and guidance.

1. obtain the relevant information to carry out the work activities in accordance with organisational procedures
2. maintain the health and safety of yourself and others at all times, in accordance with the relevant legislation and codes of practice
3. assess the risks associated with the site and the work to be carried out, before starting work and throughout the activity, checking and confirming the findings of any existing risk assessments
4. check any statutory requirements that might be in place that may prohibit or place conditions on the work to be done
5. confirm that appropriate personal protective equipment (PPE) for the work to be carried out is worn at all times
6. identify the area of standing trees to be assessed and marked
7. complete pre-tariff procedure to establish the appropriate sampling scheme and, if thinning, the required intensity
8. measure and assess the volume of standing trees in line with the information provided and the appropriate tariff
9. complete the appropriate tariffing field checks to ensure the elimination of errors
10. mark the stand for harvesting and extraction, including the extraction system
11. carry out ongoing basal area assessments in the case of thinning works to ensure the correct volume is removed
12. minimise damage or disturbance to the site and surrounding area while carrying out this work, and confirm that the site is left in a safe and tidy condition
13. complete and store all relevant documentation in accordance with the relevant legal requirements and organisational procedures

1. how to identify and access information relevant to the required work
2. how to identify hazards and assess risks associated with the site and the work to be carried out
3. the relevant health and safety procedures and Safe Systems of Work (SSW)
4. current legislation and codes of practice, industry standards and guidance, organisational policies, procedures and protocols, business and professional ethics that are relevant to your area of work and to which you must adhere
5. the selection, use and care of personal protective equipment (PPE)
6. navigational and mapping techniques and how to use these
7. how to identify the species of standing trees
8. how to measure standing timber and what needs to be considered when assessing the volume of standing trees
9. how to use forest and woodland mensuration techniques
10. the tariff procedure and how it works
11. how to use full and abbreviated tariffing systems
12. the product specifications, including quality, minimum and maximum lengths and minimum and maximum diameters
13. the available products and markets
14. how to measure thinning yield, thinning intensity and basal area
15. when it is appropriate to fell a volume of sample trees
16. the criteria for deciding between selective and systematic methods of selection
17. the significance of thinning types on selection and marking, covering low, intermediate, crown and line
18. how to mark stand, extraction system and thinning requirements
19. the implications of terrain, season, weather and species
20. the potential impact of the work on the site and surrounding area and how this can be minimised
21. your and the organisation’s responsibility for protecting the environment and working sustainably
22. the legal and organisational requirements for the completion and storage of documentation

Considerations when assessing the volume of standing trees:
• thinning intensity
• thinning yield
• sample plot
• rack spacing
• rack width
• product
• brash mat
• windthrow hazard classification
• working methods
• silvicultural systems
• species of tree
• extraction method

Basal area of an individual tree is the cross-sectional area of the tree at its breast height point

Information required to carry out work activities could include:
• drawings
• plans
• schedules
• specifications
• method statements
• Standard Operating Procedures (SOPs)
• manufacturer’s instructions
• customer requirements
• quality assurance requirements
• industry standards (e.g. British Standards)
• verbal or written instructions
• industry guidance (e.g. Forestry Commission Mensuration Handbook)

Organisational procedures refer to procedures set by the organisation you are employed by or the organisation that you are doing the work on behalf of (the client or customer)

Product specifications e.g. fencing posts, telegraph poles

Safe System of Work (SSW) – is a method of work that puts in place control measures arising from a risk assessment, in order to manage identified hazards, which are broken down into four elements: safe person; safe equipment; safe place; and safe practice.

Tariff procedure includes the three basic steps in estimating the volume of a stand of trees

Tariffs are a series of pre-constructed “local” volume tables