January 2014 : News from the Park: What is happening about the hedgerows?

You may have noticed the changes to the old hedgerow by the tennis courts in Stratton Park.

What is the purpose?

A hedgerow once established does need to be maintained – nothing comes for free.  If managed properly a hedgerow will last for  500 years.  If neglected it will end up looking like our hedgerow. Our  hedge was planted in the 19th century, we are not sure when, definitely  after 1790 and possibly as late as  1890.

Right up to the 19th century a hedgerow was created to mark a boundary -  a field boundary  or a property boundary. This is in the days before barbed wire and electric cattle fencing , so  a hedge was  created with prickly shrubs -  hawthorn and blackthorn which discouraged cattle from pushing through. To  remain effective the hedge needed to  be maintained regularly by trimming  the top and sides or it would develop gaps. The hedge row would be created by digging two  small parallel ditches with the earth  piled up between them,. The bank would then be planted with hawthorns, interspersed with hazel, crab apple, blackthorn, elder and field maple. The 19th century practice was then to plant  young English hardwoods at intervals -  ash, elm, beech and oak.

The individual English hardwood trees along a hedgerow can last  up to 300 years having reached maturity  in 100 – 150 years, after which they are in decline and will gradually  decay. New  replacement hardwoods can be planted but they will struggle  because the  ground is already  colonised by the roots of the other  trees and bushes on the hedge line.

The  constituents of the hedge itself will last hundreds of years if managed properly –  trimmed or layed to keep it compact. Hedgerow shrubs differ from trees in that they do not develop just one main stem but many stems from the base, and indeed are happy to  keep generating new stems if  the older ones are cut back. Again ,unlike a tree, they  cannot support  growth above  15 – 20 feet tall.

The technique of laying involves cutting much of the growth back to the ground and partially cutting through the main upright healthy branches at base leaving just 30 % of the  thickness of each still in place. The  branch is then bent over to a 45% angle or more and held down by stakes and  hazel  bindings.. This sounds  very drastic but done properly the hedge is rejuvenated and will  grow and  prosper for another  30 – 40 years before needing renovation again.

A newly layed hedge

 

 

 

 

 

A rejuvenated hedge layed a few years previously

 

 

If however the hedge  shrubs are allowed to  just grow unchecked for  40 – 50 years they will become to old and too stiff to be layed in this way. Even worse, if the sides of the hedge are trimmed back regularly but  the top is allowed to continue to grow upwards, the hawthorn, the main element in the hedge,  will grow to 10 – 15 feet tall, become over mature and then decay and fall over.

That is what has happened with our hedge.- it is too old to lay and too old to  cut back to a hedge shape.

In the longer term, as sections die and fall ,  partial regeneration by cutting back to base  and some new planting  is our best option. This is what has happened at the southern end of the hedge nearest the Car Park. Of the 5 original hawthorn roots in this section 3 had fallen and  on close inspection one other was completely decayed – held up only by the ivy on it. The decision was taken to  reduce all 5  shrubs  to their root bases and cut back the rose briar and other small shrubs at the side of the stumps. To keep the hedgerow line and  offer a rich habitat for invertebrates etc.  much of the material has been retained in a ‘dead hedge’ . Some of the roots below this material may regenerate and sprout new growth over the next two years – but this is not guaranteed from such decayed roots -  we will have to wait and see.

Meanwhile new young hawthorn and hazel shrubs will be planted along side the  dead hedging and in 15 years we may  well have a young and thriving new hedge -  but only if it is properly maintained.

Further along the hedgerow  we have blocked  some of the gaps up so that  young shrubs can grow to eventually fill the spaces, leaving  3 main walk-throughs. for park users. Young  hedgerwo shrubs gro very slowly here as they are competing with established tree roots. Patience is needed!

Recently, part of one of our  old crab-apple trees fell over – it was completely decayed and hollowed out at the base and finally succumbed to old age. Fortunately we have some crab apple whips  which in future  years can be used to form part of the hedgerow again.

 

 

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