Farm Hedge Woodfuel Assessment
Guidance Notes for completion of Hedge Woodfuel Recording Form and Hedge Woodfuel Assessment Tool
1.Necessary resources
- Wood Fuel from Hedges Guide (pages 14 and 15 of this have line drawings and photos of the different classes of hedge you will need to be able to identify).
- Maps of the farm and preferably aerial photographs.
- Hedge Woodfuel Recording Form.
- If possible, aerial photos. Before visiting the farm it may be possible to use these to identify hedges which need not be assessed for environmental or other reasons (see below), to save time.
2. Hedges to record/exclude
On most farms it will be possible and advisable to exclude up to 50% of hedges from the woodfuel management rotation for practical, safety, access, landscape, wildlife or pest (e.g. rabbits and deer) reasons. The landowner should be consulted before the survey begins for this reason and also to establish practical limits, e.g. slopes that are too steep, or land that is too wet to access safely or efficiently for fuel harvesting.
Hedges which should not be managed mainly for woodfueland so need not be surveyed could include:
- Farm boundary hedges with a neighbour or along a road where there may be issues affecting management for woodfuel.
- Hedges with high biodiversity value – e.g. with many veteran or candidate veteran trees, or which are known to be of particular importance for protected species such as dormice, bats or cirl buntings.
- Hedges with high historical or landscape value – e.g. lines of beech trees where they add landscape character.
- Hedges next to Public Rights of Way where a future fuel-managed hedge would obstruct a well-loved path or view.
3. Completing the recording sheet
Allocate a reference number to each hedge to be surveyed and record it on the farm map.
Walk the length of the selected hedge (one side), and identify any large differences in hedge structure or species. Most hedges will be more or less uniform along their length, but very occasionally hedges may have two or more distinct forms. Ignore any differences created by the dominance of one particular species or another over a short stretch, focusing only on major, striking differences.
Place each uniform length into one of the hedge type classes, identify main tree or shrub species (by frequency not cover), assess growth vigour (high, medium, low), estimateproportion occupied by gaps, and measure (from maps) its length. Fill in the information gained on the Hedge Recording Sheet against the relevant hedge reference number.
It is important that identification of the main tree or shrub species in a hedge should be done by looking at the frequency of each species, not by how much space its canopy currently covers. This is because cover will vary hugely with the growth state of the hedge, while frequency will remain more or less the same. So, for each species try and assess what proportion of the main stems in the hedge belong to it – this will give you its frequency.
The classic pre-enclosure West Country Hedge will probably be a mixed hedge with hawthorn, blackthorn, hazel, willow and a scattering of tree species such as oak, ash or sycamore. These can be recorded as mixed hedges. If however there is a clear section occupying a significant length of the hedge dominated by one species, then record that section separately. This would be especially important if the species concerned was willow or ash as both have a higher fuel value, or hawthorn or blackthorn as they both have a lower fuel value.
Record the presence of mature hedgerow trees or other notable trees in the Notes section but do not include them in calculations – they should not normally be harvested for fuel wood. Also note high levels of rabbit or deer damage, hedges under such pressure may require fencing to be useful for fuel.
Before you enter the data in the spreadsheet you will need to know the lengths of the hedges, or subsections of hedges. This can be assessed in the field or later by measuring using a GIS tool on a website such as MAGIC or by hand on a scaled map.