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Hedge structures

The hedge structures below tie in neatly with the hedgerow management cycle. When deciding which structure best represents the hedgerow you are surveying, it can help to look at the management cycle for context. 

The heights given in these descriptions are for guide purposes only, and you should not base your hedge structure decision on height alone, as the other condition descriptors are more accurate. A 3m hedge can still be over-trimmed H1 if it is repeatedly cut to the same height and will develop all the other symptoms of an over-trimmed hedge. Similarly, a 3m hedge could be a tall and overgrown hedge depending on the species of the hedge. 

Jump to:  Dense and well managed hedges  |  Over-trimmed hedges  |  Tall or overgrown hedges  |  Recently rejuvenated hedges

Dense and well managed hedges

These dense and well managed hedges provide the core hedge types within the healthy hedgerow management cycle and it is good to aim for the majority of the hedges in a particular farm or estate to be in these conditions. 

H5 Dense and Managed

  • Healthy dense hedgerow
  • Has obviously been trimmed in the fairly recent past. (May have shoots protruding but retains basic shape)
  • Frequent healthy stems
  • Dense amongst most of their length
  • About 2m or more in height

 

H6 Dense and managed

  • Healthy dense hedgerow not recently trimmed.
  • May have ‘straggly’ appearance with protruding woody branches
  • May be in a non-intervention stage of management
  • May be on a longer trim rotation, e.g. 3 year cut
  • About 3m or more in height

H7 Dense and managed

  • May have a straggly appearance with numerous long woody branches protruding from the main body
  • Usually still quite dense, but increasing volume may start to shade the lower branches
  • Has frequent healthy stems, about 4m high.
  • This is an unmanaged, overgrown version of H6

Over-trimmed hedges

When trimmed to the same height and width repeatedly, the structure of the hedge starts to deteriorate, no hedge can be kept at eh same point in the management cycle indefinitely without causing damage to the condition of the hedge. It will start to form features symptomatic of this management such as a hard knuckle of plant scar tissue at the trim line, it may start to lose stems and become gappy, and eventually would be lost altogether. Over-trimmed hedges are often on the smaller side, but this isn't always the case; any size hedge will show these symptoms if trimmed too often or always to the same height.

H3 Over-trimmed

  • Over-trimmed, hard knuckle may be starting to form
  • Still has frequent healthy stems
  • Base canopy may or may not extend to the ground

 

 

 

H2 Over-trimmed

  • Over-trimmed, hard knuckle at trim line
  • Infrequent stems
  • May be developing mushroom shaped growth form
  • Often low and narrow
  • Closely and frequently flailed to the same line
  • May lack branches and foliage in the lower parts
  • Base canopy may or may not extend to the ground

H1 Over-trimmed

  • Heavily over-trimmed, hard knuckle at trim line
  • Many gaps, sparse stems
  • Bases may be gnarled or rotting
  • Usually low and narrow
  • May be invaded by elder, sycamore or other invasive sp.
  • Lacks branches and foliage in the lower parts
  • Closely and frequently flailed to the same line

Tall and overgrown hedges

If left without any management for a long time, hedges will start to become tall and overgrown. Thilst there are some species that benefit from the earlier stages of overgrown hedges, this trend begins the process where the base of the hedge is shaded out and so it loses its valuavble undergrowth. If left indefinately it will lose all its shrubby base vegetation and turn into a line of trees. Although this may not sound so bad, lines of trees are very difficult to return to the hedgerow condition, and are not as valuable as a wildlife corridor for many of our native species. 

H8 Tall or overgrown

  • Over-mature hedgerow, tall and leggy
  • May have spreading tops
  • Not been trimmed for many years
  • Lacks significant foliage in the lower parts
  • Stems still healthy, but may be infrequent and getting too large to lay

H9 Tall or overgrown

  • Over-mature hedgerow, tall and leggy
  • Spreading tops might be dying back
  • Collapse possible
  • No significant woody foliage in the lower parts
  • May be developing gaps

 

H10 Tall or overgrown – line of trees

  • Hedgerow has developed into a line of trees
  • Very little, if any, woody undergrowth

 

Recently rejuvenated hedges

Every hedge, no matter how well it is managed, will need to be structurally rejuvenated at some point in its life. Rejuvenation such as laying, coppicing and (re) planting can also be used to help bring unhealthy hedges back into the healthy management cycle.

H4a Rejuvenated - Recently laid

  • Hedge stems cut at base and laid on their sides.
  • Depending on time since being laid, significant re-growth may have grown from the base. The horizontal stems (alive or dead) should still be visible
  • Approximately laid within the last 5 years

 

 

H4b Rejuvenated - Recently coppiced

  • Stems all cut at ground level, stumps may be visible
  • Significant regrowth may be visible from cut bases
  • Approximately coppiced within the last 5 years

 

 

H4c Rejuvenated - Recently planted

  • Approximately planted within the last 5 years
  • Stems may still be protected by tree guards

 

PTES Hedgerow Survey

Current Hedgerow Statistics

Length of
hedgerow surveyed

545 km

Average number of woody species
reported per 30m

3.6

% hedges in each
main structure category

  • 52.5 Overtrimmed
  • 27.1 Dense and managed
  • 13.6 Tall and overgrown
  • 6.8 Recently rejuvenated

Average trees/100m

12.8