Ancient and semi-natural woodland and protected areas
The information in Table 5.2 and most of Table 5.1 has been reproduced from Protected Forest Areas in the UK (S Pryor & G Peterken, 2001) (not National Statistics). It had been derived from a variety of sources, and is unlikely to give a wholly accurate inventory of protected areas in the United Kingdom.
The woodland categories used in Table 5.1 are:
- ASNW: (ancient semi-natural woodland) both ancient and semi-natural.
- PAWS: (plantation on an ancient woodland site) ancient in the sense of continuously wooded over a long period but not semi-natural.
- OSNW: (other semi-natural woodland) semi-natural but not ancient.
The types of statutory protection in Table 5.2 are:
- SAC: Special Area of Conservation;
- SPA: Special Protection Area;
- NNR: National Nature Reserve;
- SSSI: Site of Special Scientific Interest (ASSI in Northern Ireland).
Data about the small amount of ancient woodland in Northern Ireland was not available in 2001, but has been added using the report Back on the Map (Woodland Trust, 2007) (not National Statistics).
Revised estimates for Wales were compiled for Woodland for Wales progress report 2001-05 (2006) (not National Statistics). In this edition of Forestry Statistics, they have been used for Wales in place of the estimates from Pryor & Peterken (2001), and the UK totals have been revised accordingly.
The UK Indicators of Sustainable Forestry (indicator B1) published in 2002 used results from a different source: Pryor & Smith (2002). This was an updated estimate of ancient woodland area derived by overlaying the 1995-99 National Inventory of Woodland and Trees digital map onto ancient woodland inventories. This gave lower figures than those published in Pryor & Peterken (2001). At the time, Pryor & Smith (2002) was thought to give the best estimates of ancient woodland area. However, further investigation of the discrepancies between the 1995-99 National Inventory of Woodland and Trees and the ancient woodland inventories suggests that some discrepancies are due to differences in spatial registration of woods, and that some areas of ancient woodland are incorrectly omitted from the totals in Pryor & Smith (2002). In consequence, the estimates from Pryor & Peterken (2001) are now recommended for use, until better information becomes available.
The Ancient Woodland Inventory data sets for England and Wales are currently being revised. New estimates for Scotland will become available from the Native Woodland Survey of Scotland.
Populations of wild birds
Population indices for wild birds are a framework indicator for sustainable development. The data published here are based on those published in the Wild Bird Populations statistics release (Defra, January 2011), rescaled here to give year 2000 = 100 instead of year 1970 = 100. Further data and analysis about populations of wild birds are in Defra Wildlife KeyFacts.
The index for woodland specialists was recalculated in 2007 to include 4 additional species; this affected the indices for total woodland birds and (to a lesser extent) all birds.
This indicator, which shows the overall condition and richness of flora in woodland, is derived from data collected by the Countryside Survey in 2007 (not National Statistics) and previous surveys in 1998 and 1990. Results were published in late 2008.
No similar samples were taken in the Northern Ireland Countryside Survey.