Friday, 21 December 2012

Latest forest Inventory reports published

The Forestry Commission have released the latest National Forest Inventory (NFI) which estimates quantities of broadleaved species in British woodlands.  Due to the outbreak of ash dieback (Chalara) this edition of the NFI has a special focus on ash.

The NFI provides a record of the size and distribution of forests and woodlands in Great Britain and information on key forest attributes. 
Total woodland cover with
proportion of ash by NFI region

This report provides estimates of the stocked area, numbers of trees and standing volume in living broadleaved trees within forests and woodlands in Great Britain as at 31 March 2011.

The report provides a particular focus on the ash species, expressing estimates of quantities of ash in the context of quantities of all broadleaved species. 

Information in this report includes estimates for England, Scotland and Wales, and individual regions within England and Scotland, each broken down by Forestry Commission and private sector ownership. 

Stocked area by principal broadleaved species
Estimates are also provided for individual age and size classes of the broadleaved and ash tree populations.

More detailed reports and analysis can be found on the Forestry Commission website here.

Key Findings

  • The estimated stocked area of broadleaves within Great Britain is 1.3 million hectares
    • 142 thousand ha is ash (or 11% of all broadleaves and 5% of all species (both conifer and broadleaves).
  • There are 1.4 billion broadleaved trees in British woodlands of over 0.5 hectares (of which ash trees are estimated to number 126 million)
  • In addition, there are an estimated 4.2 billion broadleaved seedlings and saplings in British private sector woodlands
    • of which ash constitutes an estimated 39%.
  • Total broadleaved standing volume on the private sector estate is estimated to be 227 million m3
    • the estimate for the Forestry Commission estate is 13 million m3.
  • Ash accounts for approximately 14% of total broadleaved standing volume in Great Britain.
  • Ash tends to be younger and marginally smaller than broadleaved species as a whole:
    • Trees aged between 20 and 100 years account for most broadleaved standing volume; while for ash very little is over 80 years of age.
Information on the amount and distribution of ash trees outside NFI woodland can be found on the Countryside Survey website. This report includes small copses of less than 0.5 hectares, linear features containing trees less than 5 metres in width (including hedgerows and lines of trees) and individual trees (including some veterans).

The key findings from this report are as follows:
  • Key Findings The estimated area of ash in Broadleaved woodlands <0.5ha in size is 21.69 000ha.
  • Ash is found in different landscape components, in fields and field boundaries, alongside rivers and streams and particularly in hedgerows.
  • Ash is the fourth most abundant tree species in small woodland patches (<0.5ha) in GB after Oak, Birch and Hawthorn.
  • It is more abundant in England (12.1 000ha) than Scotland or Wales but in England Sycamore and Beech are also abundant.
  • There are estimated to be 2.7 million individual ash trees (outside of woodland) in the countryside and ash is the 2nd most common species of individual tree.
  • Most ash trees tended to be in low to mid-range DbH categories i.e. >40% between 21 and 50cm DbH.
  • There were very few veteran ash trees.
  • Ash is the most common hedgerow tree species (i.e. species growing as a full standard as part of a hedgerow).
  • The estimated length of woody linear features (hedgerows and lines of trees) composed of ash is 98.9 000km across GB with most of this (86.1 000 km) found in England.
  • In analyses based on repeated vegetation plots ash trees increased in number of plots occupied on linear features, which include hedgerows, between 1978 and 2007 and in the number of area (field) plots occupied between 1990 and 2007.

No comments:

Post a Comment