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Seedling regeneration

  • Biodiversity

  • Function

Summary

Natural seedling regeneration and its diversity is a key indicator of forest regeneration, persistence and resilience (Chazdon et al. 2023). In UK forests browsing impacts from species such as deer can inhibit seedling regeneration and establishment (Gullett et al. 2023).

Tree species richness in the regeneration layer is positively related to overall richness of other taxa (Storch et al. 2023). Seedling regeneration also indirectly indicates the presence of seed dispersers, diversity of soil seedbanks and diversity of mature trees in the landscape (Chazdon and Guarigata 2016).

Methodology summary

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

The NFI Survey Manual provides the methodology:

  • How to allocate plots – Chapter 12 Plot Assessments
  • Recording young trees – Chapter 15 Young Tree Assessments

Metric threshold or direction of change

In forest ecosystems high diversity and abundance of native seedlings is desirable. Their transition to later growth stages will determine the long-term persistence of the forest habitat.

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  • Forest

Scale

  • Community

Cost

  • Low

Tier

  • Tier 2

Technical expertise

  • Low

Standardised methodology

  • Yes