Tree age

Tree age data can be collected at the same time as assessing Vegetation biomass, Vegetation structure, Seedling regeneration, and Tree diversity.

The UK National Forest Inventory (NFI) provides a standardised methodology to establish fixed area survey plots and record tree growth categories (Forestry Commission 2020). Young trees (seedlings and saplings), diameter at breast height (DBH) < 4 cm and mature trees, DBH > 4 cm, are recorded.

• Forest is defined as having >20% canopy cover.
• 0.01 ha plots (5.64m radius) are established, the number of plots is determined by the size of the forest area
• Within each plot DBH is recorded for all mature trees (DBH > 4 cm)
• Saplings (height > 50 cm, DBH < 4 cm) are recorded in a 2.52 m radius plot at the centre of each 0.01 ha plot
• Seedlings (height < 50 cm, DBH < 4 cm) are recorded in a 1.78 m radius plot at the centre of each 0.01 ha plot • All dead stems with DBH > 4 cm are recorded in the 2.52 m radius plot at the centre of each 0.01 ha plot

The NFI Survey Manual provides the methodology:

• How to allocate plots – Chapter 12 Plot Assessments
• Recording mature trees – Chapter 13 Tree Assessment Procedures
• Recording young trees – Chapter 15 Young Tree Assessments
• Recording standing deadwood – Chapter 18 Decay Classes

A methodology for categorising trees by growth stage (dependent on species) is given in Appendix 2: Field Survey Methodology of the Caledonian Pinewood Recovery Project.