National inventory

 

The woodland area of the UK is just under 12% and accounts for approximately 150 million tonnes of carbon. The National Inventory of Woodland and Trees currently provides the the definitive GB set of data on woodlands and trees.

The Forestry Commission has undertaken inventories of woodlands in Great Britain at 15–20 year intervals since 1924 and annual planting and felling data are used to update information on the size and age structure of the national forest estate in the period between inventories.. The most recent inventory was carried out between 1995 and 2000. Further woodland inventories will be carried out as a collaborative project between the Forestry Commission in England, Scotland and Wales on a rolling programme starting in 2006.

The new National Inventory of Woodland and Trees comprises two distinct elements:

• A digital woodland map of all woodland greater than 0.5ha showing broad forest type.
• A survey of other attributes derived from sample plots.

Small woods of less than 0.5 hectares together with narrow linear features and field trees will also be surveyed, but by a separate sampling method in a parallel exercise called the small woods survey.

The digital woodland map provides basic information on the size and nature of the forest estate. The sample survey provides considerable additional data on the size, species, form, and age of trees. It is also proposed to collect information on forest soil type which is a major source of stored carbon.

The woodland area together with the size and growth characteristics of trees are used in a dynamic carbon accounting model to estimate annual uptake and storage of atmospheric carbon. The growth characteristics of UK forests are continually being assessed and refined through a national system of mensuration plots and associated yield models.